SONAR-6589 replace usage of ComputationContext.getRoot with TreeRootHolder

also, ComponentTree is now computed as a step in BuildComponentTreeStep

22 files changed, 599 insertions, 202 deletions

diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/ComputationContext.java b/server/sonar-server/src/main/java/org/sonar/server/computation/ComputationContext.java
index d6a2c75e309..27fd4debf36 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/ComputationContext.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/ComputationContext.java
@@ -22,14 +22,13 @@ package org.sonar.server.computation;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.ComponentTreeBuilder;
 
-public class ComputationContext implements org.sonar.server.computation.context.ComputationContext {
+public class ComputationContext {
   private final Component component;
 
   public ComputationContext(ComponentTreeBuilder componentTreeBuilder) {
     this.component = componentTreeBuilder.build();
   }
 
-  @Override
   public Component getRoot() {
     return component;
   }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/component/ComponentTreeBuilder.java b/server/sonar-server/src/main/java/org/sonar/server/computation/component/ComponentTreeBuilder.java
index f2089cf7589..622185d5cc3 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/component/ComponentTreeBuilder.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/component/ComponentTreeBuilder.java
@@ -21,8 +21,7 @@ package org.sonar.server.computation.component;
 
 public interface ComponentTreeBuilder {
   /**
-   * Builds the tree of components for the specified ComputationContext and returns the Component of the root of this
-   * tree.
+   * Builds the tree of components and returns the Component of the root of this tree.
    */
   Component build();
 }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/component/MutableTreeRootHolder.java b/server/sonar-server/src/main/java/org/sonar/server/computation/component/MutableTreeRootHolder.java
new file mode 100644
index 00000000000..f4873dfc567
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/component/MutableTreeRootHolder.java
@@ -0,0 +1,33 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.component;
+
+public interface MutableTreeRootHolder extends TreeRootHolder {
+
+  /**
+   * Sets the root of the component tree in the TreeRootHolder. Settings a root more than once is allowed but it can
+   * never be set to {@code null}.
+   *
+   * @param newRoot a {@link Component}, can not be {@code null}
+   *                
+   * @throws NullPointerException if {@code newRoot} is {@code null}
+   */
+  void setRoot(Component newRoot);
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/context/ComputationContext.java b/server/sonar-server/src/main/java/org/sonar/server/computation/component/TreeRootHolder.java
index 9a0a838ae6c..4b990fc9845 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/context/ComputationContext.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/component/TreeRootHolder.java
@@ -17,12 +17,13 @@
  * along with this program; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
-package org.sonar.server.computation.context;
-
-import org.sonar.server.computation.component.Component;
-
-public interface ComputationContext {
+package org.sonar.server.computation.component;
 
+public interface TreeRootHolder {
+  /**
+   * The root of the tree of Component representing the component in the current BatchReport.
+   *
+   * @throws IllegalStateException if the holder is empty (ie. there is no root yet)
+   */
   Component getRoot();
-
 }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/component/TreeRootHolderImpl.java b/server/sonar-server/src/main/java/org/sonar/server/computation/component/TreeRootHolderImpl.java
new file mode 100644
index 00000000000..1be5c91b1b0
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/component/TreeRootHolderImpl.java
@@ -0,0 +1,42 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.component;
+
+import java.util.Objects;
+
+/**
+ * Holds the reference to the root of the {@link Component} tree for the current CE run.
+ */
+public class TreeRootHolderImpl implements MutableTreeRootHolder {
+  private Component root;
+
+  @Override
+  public void setRoot(Component newRoot) {
+    this.root = Objects.requireNonNull(newRoot);
+  }
+
+  @Override
+  public Component getRoot() {
+    if (this.root == null) {
+      throw new IllegalStateException("Root has not been created yet");
+    }
+    return this.root;
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/container/ComputeEngineContainerImpl.java b/server/sonar-server/src/main/java/org/sonar/server/computation/container/ComputeEngineContainerImpl.java
index a6a62dc8d2f..1f1f7336c6d 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/container/ComputeEngineContainerImpl.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/container/ComputeEngineContainerImpl.java
@@ -37,6 +37,7 @@ import org.sonar.server.computation.activity.ActivityManager;
 import org.sonar.server.computation.batch.BatchReportReaderImpl;
 import org.sonar.server.computation.batch.ReportExtractor;
 import org.sonar.server.computation.component.DbComponentsRefCache;
+import org.sonar.server.computation.component.TreeRootHolderImpl;
 import org.sonar.server.computation.event.EventRepositoryImpl;
 import org.sonar.server.computation.component.ProjectSettingsRepository;
 import org.sonar.server.computation.issue.IssueCache;
@@ -113,6 +114,8 @@ public class ComputeEngineContainerImpl extends ComponentContainer implements Co
       ReportExtractor.class,
       BatchReportReaderImpl.class,
 
+      TreeRootHolderImpl.class,
+
       // repositories
       PlatformLanguageRepository.class,
       MeasureRepositoryImpl.class,
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/BuildComponentTreeStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/BuildComponentTreeStep.java
new file mode 100644
index 00000000000..b97b66c095f
--- /dev/null
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/BuildComponentTreeStep.java
@@ -0,0 +1,72 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.step;
+
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
+import javax.annotation.Nonnull;
+import org.sonar.batch.protocol.output.BatchReport;
+import org.sonar.server.computation.ComputationContext;
+import org.sonar.server.computation.batch.BatchReportReader;
+import org.sonar.server.computation.component.Component;
+import org.sonar.server.computation.component.ComponentImpl;
+import org.sonar.server.computation.component.MutableTreeRootHolder;
+
+/**
+ * Populates the {@link MutableTreeRootHolder} from the {@link BatchReportReader}
+ */
+public class BuildComponentTreeStep implements ComputationStep {
+  private final BatchReportReader reportReader;
+  private final MutableTreeRootHolder mutableTreeRootHolder;
+
+  public BuildComponentTreeStep(BatchReportReader reportReader, MutableTreeRootHolder mutableTreeRootHolder) {
+    this.reportReader = reportReader;
+    this.mutableTreeRootHolder = mutableTreeRootHolder;
+  }
+
+  @Override
+  public void execute(ComputationContext context) {
+    mutableTreeRootHolder.setRoot(buildComponentRoot());
+  }
+
+  private Component buildComponentRoot() {
+    int rootComponentRef = reportReader.readMetadata().getRootComponentRef();
+    BatchReport.Component component = reportReader.readComponent(rootComponentRef);
+    return new ComponentImpl(component, buildChildren(component));
+  }
+
+  private Iterable<Component> buildChildren(BatchReport.Component component) {
+    return Iterables.transform(
+        component.getChildRefList(),
+        new Function<Integer, Component>() {
+          @Override
+          public Component apply(@Nonnull Integer componentRef) {
+            BatchReport.Component component = reportReader.readComponent(componentRef);
+            return new ComponentImpl(component, buildChildren(component));
+          }
+        }
+    );
+  }
+
+  @Override
+  public String getDescription() {
+    return "Builds the Component tree";
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/ComputationSteps.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/ComputationSteps.java
index 831299548c6..7d409691a77 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/step/ComputationSteps.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/ComputationSteps.java
@@ -36,6 +36,9 @@ public class ComputationSteps {
    */
   public List<Class<? extends ComputationStep>> orderedStepClasses() {
     return Arrays.asList(
+      // Builds Component tree
+      BuildComponentTreeStep.class,
+
       PopulateComponentsUuidAndKeyStep.class,
       ValidateProjectStep.class,
 
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/ParseReportStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/ParseReportStep.java
index 28edc272344..5bd66a86445 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/step/ParseReportStep.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/ParseReportStep.java
@@ -26,22 +26,25 @@ import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReader;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.DepthTraversalTypeAwareVisitor;
+import org.sonar.server.computation.component.TreeRootHolder;
 import org.sonar.server.computation.issue.IssueComputation;
 
 public class ParseReportStep implements ComputationStep {
 
   private final IssueComputation issueComputation;
   private final BatchReportReader reportReader;
+  private final TreeRootHolder treeRootHolder;
 
-  public ParseReportStep(IssueComputation issueComputation, BatchReportReader reportReader) {
+  public ParseReportStep(IssueComputation issueComputation, BatchReportReader reportReader, TreeRootHolder treeRootHolder) {
     this.issueComputation = issueComputation;
     this.reportReader = reportReader;
+    this.treeRootHolder = treeRootHolder;
   }
 
   @Override
   public void execute(ComputationContext context) {
     IssueDepthTraversalTypeAwareVisitor visitor = new IssueDepthTraversalTypeAwareVisitor();
-    visitor.visit(context.getRoot());
+    visitor.visit(treeRootHolder.getRoot());
     processDeletedComponents(visitor);
     issueComputation.afterReportProcessing();
   }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistComponentsStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistComponentsStep.java
index df2dfad32c9..1e714fa0166 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistComponentsStep.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistComponentsStep.java
@@ -36,6 +36,7 @@ import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReader;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.DbComponentsRefCache;
+import org.sonar.server.computation.component.TreeRootHolder;
 import org.sonar.server.db.DbClient;
 
 public class PersistComponentsStep implements ComputationStep {
@@ -43,18 +44,20 @@ public class PersistComponentsStep implements ComputationStep {
   private final DbClient dbClient;
   private final DbComponentsRefCache dbComponentsRefCache;
   private final BatchReportReader reportReader;
+  private final TreeRootHolder treeRootHolder;
 
-  public PersistComponentsStep(DbClient dbClient, DbComponentsRefCache dbComponentsRefCache, BatchReportReader reportReader) {
+  public PersistComponentsStep(DbClient dbClient, DbComponentsRefCache dbComponentsRefCache, BatchReportReader reportReader, TreeRootHolder treeRootHolder) {
     this.dbClient = dbClient;
     this.dbComponentsRefCache = dbComponentsRefCache;
     this.reportReader = reportReader;
+    this.treeRootHolder = treeRootHolder;
   }
 
   @Override
   public void execute(ComputationContext context) {
     DbSession session = dbClient.openSession(false);
     try {
-      Component root = context.getRoot();
+      Component root = treeRootHolder.getRoot();
       List<ComponentDto> components = dbClient.componentDao().selectComponentsFromProjectKey(session, root.getKey());
       Map<String, ComponentDto> componentDtosByKey = componentDtosByKey(components);
       ComponentContext componentContext = new ComponentContext(session, componentDtosByKey);
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistTestsStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistTestsStep.java
index 07e9b997c95..afc35022814 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistTestsStep.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/PersistTestsStep.java
@@ -49,6 +49,7 @@ import org.sonar.server.computation.batch.BatchReportReader;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.DbComponentsRefCache;
 import org.sonar.server.computation.component.DepthTraversalTypeAwareVisitor;
+import org.sonar.server.computation.component.TreeRootHolder;
 import org.sonar.server.db.DbClient;
 import org.sonar.server.source.db.FileSourceDb;
 import org.sonar.server.source.db.FileSourceDb.Test.TestStatus;
@@ -62,20 +63,22 @@ public class PersistTestsStep implements ComputationStep {
   private final System2 system;
   private final DbComponentsRefCache dbComponentsRefCache;
   private final BatchReportReader reportReader;
+  private final TreeRootHolder treeRootHolder;
 
-  public PersistTestsStep(DbClient dbClient, System2 system, DbComponentsRefCache dbComponentsRefCache, BatchReportReader reportReader) {
+  public PersistTestsStep(DbClient dbClient, System2 system, DbComponentsRefCache dbComponentsRefCache, BatchReportReader reportReader, TreeRootHolder treeRootHolder) {
     this.dbClient = dbClient;
     this.system = system;
     this.dbComponentsRefCache = dbComponentsRefCache;
     this.reportReader = reportReader;
+    this.treeRootHolder = treeRootHolder;
   }
 
   @Override
   public void execute(final ComputationContext context) {
     DbSession session = dbClient.openSession(true);
     try {
-      TestDepthTraversalTypeAwareVisitor visitor = new TestDepthTraversalTypeAwareVisitor(context, session, dbComponentsRefCache);
-      visitor.visit(context.getRoot());
+      TestDepthTraversalTypeAwareVisitor visitor = new TestDepthTraversalTypeAwareVisitor(session, dbComponentsRefCache);
+      visitor.visit(treeRootHolder.getRoot());
       session.commit();
       if (visitor.hasUnprocessedCoverageDetails) {
         String projectKey = dbComponentsRefCache.getByRef(reportReader.readMetadata().getRootComponentRef()).getKey();
@@ -98,14 +101,14 @@ public class PersistTestsStep implements ComputationStep {
     final String projectUuid;
     boolean hasUnprocessedCoverageDetails = false;
 
-    public TestDepthTraversalTypeAwareVisitor(ComputationContext context, DbSession session, DbComponentsRefCache dbComponentsRefCache) {
+    public TestDepthTraversalTypeAwareVisitor(DbSession session, DbComponentsRefCache dbComponentsRefCache) {
       super(Component.Type.FILE, Order.PRE_ORDER);
       this.session = session;
       this.dbComponentsRefCache = dbComponentsRefCache;
       this.existingFileSourcesByUuid = new HashMap<>();
-      this.projectUuid = context.getRoot().getUuid();
+      this.projectUuid = treeRootHolder.getRoot().getUuid();
       session.select("org.sonar.core.source.db.FileSourceMapper.selectHashesForProject",
-        ImmutableMap.of("projectUuid", context.getRoot().getUuid(), "dataType", Type.TEST),
+        ImmutableMap.of("projectUuid", treeRootHolder.getRoot().getUuid(), "dataType", Type.TEST),
         new ResultHandler() {
           @Override
           public void handleResult(ResultContext context) {
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStep.java
index cb0f362f0bb..e67d28f72cb 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStep.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStep.java
@@ -33,6 +33,7 @@ import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReader;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.ComponentImpl;
+import org.sonar.server.computation.component.TreeRootHolder;
 import org.sonar.server.db.DbClient;
 
 /**
@@ -42,10 +43,12 @@ public class PopulateComponentsUuidAndKeyStep implements ComputationStep {
 
   private final DbClient dbClient;
   private final BatchReportReader reportReader;
+  private final TreeRootHolder treeRootHolder;
 
-  public PopulateComponentsUuidAndKeyStep(DbClient dbClient, BatchReportReader reportReader) {
+  public PopulateComponentsUuidAndKeyStep(DbClient dbClient, BatchReportReader reportReader, TreeRootHolder treeRootHolder) {
     this.dbClient = dbClient;
     this.reportReader = reportReader;
+    this.treeRootHolder = treeRootHolder;
   }
 
   @Override
@@ -65,7 +68,7 @@ public class PopulateComponentsUuidAndKeyStep implements ComputationStep {
 
       ComponentContext componentContext = new ComponentContext(reportReader, componentUuidsByKey, branch);
 
-      Component root = context.getRoot();
+      Component root = treeRootHolder.getRoot();
       processProject(componentContext, root, projectKey);
       processChildren(componentContext, root, root);
       session.commit();
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/step/QualityProfileEventsStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/step/QualityProfileEventsStep.java
index ab85fb602af..ffc212081c6 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/step/QualityProfileEventsStep.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/step/QualityProfileEventsStep.java
@@ -21,6 +21,9 @@ package org.sonar.server.computation.step;
 
 import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableSortedMap;
+import java.util.Date;
+import java.util.Map;
+import javax.annotation.Nullable;
 import org.apache.commons.lang.time.DateUtils;
 import org.sonar.api.measures.CoreMetrics;
 import org.sonar.api.resources.Language;
@@ -31,6 +34,7 @@ import org.sonar.core.measure.db.MeasureDto;
 import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.DepthTraversalTypeAwareVisitor;
+import org.sonar.server.computation.component.TreeRootHolder;
 import org.sonar.server.computation.event.Event;
 import org.sonar.server.computation.event.EventRepository;
 import org.sonar.server.computation.language.LanguageRepository;
@@ -38,19 +42,17 @@ import org.sonar.server.computation.measure.MeasureRepository;
 import org.sonar.server.computation.qualityprofile.QPMeasureData;
 import org.sonar.server.computation.qualityprofile.QualityProfile;
 
-import javax.annotation.Nullable;
-
-import java.util.Date;
-import java.util.Map;
-
 import static org.sonar.server.computation.component.DepthTraversalTypeAwareVisitor.Order.POST_ORDER;
 
 public class QualityProfileEventsStep implements ComputationStep {
+  private final TreeRootHolder treeRootHolder;
   private final MeasureRepository measureRepository;
   private final EventRepository eventRepository;
   private final LanguageRepository languageRepository;
 
-  public QualityProfileEventsStep(MeasureRepository measureRepository, EventRepository eventRepository, LanguageRepository languageRepository) {
+  public QualityProfileEventsStep(TreeRootHolder treeRootHolder,
+    MeasureRepository measureRepository, EventRepository eventRepository, LanguageRepository languageRepository) {
+    this.treeRootHolder = treeRootHolder;
     this.measureRepository = measureRepository;
     this.eventRepository = eventRepository;
     this.languageRepository = languageRepository;
@@ -63,7 +65,7 @@ public class QualityProfileEventsStep implements ComputationStep {
       public void visitProject(Component tree) {
         executeForProject(tree);
       }
-    }.visit(context.getRoot());
+    }.visit(treeRootHolder.getRoot());
   }
 
   private void executeForProject(Component projectComponent) {
@@ -108,9 +110,9 @@ public class QualityProfileEventsStep implements ComputationStep {
     Date from = previousProfile.getRulesUpdatedAt();
 
     String data = KeyValueFormat.format(ImmutableSortedMap.of(
-        "key", profile.getQpKey(),
-        "from", UtcDateUtils.formatDateTime(fixDate(from)),
-        "to", UtcDateUtils.formatDateTime(fixDate(profile.getRulesUpdatedAt()))));
+      "key", profile.getQpKey(),
+      "from", UtcDateUtils.formatDateTime(fixDate(from)),
+      "to", UtcDateUtils.formatDateTime(fixDate(profile.getRulesUpdatedAt()))));
     eventRepository.add(component, createQProfileEvent(component, profile, "Changes in %s", data));
   }
 
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/batch/TreeRootHolderRule.java b/server/sonar-server/src/test/java/org/sonar/server/computation/batch/TreeRootHolderRule.java
new file mode 100644
index 00000000000..b3ca3251ddd
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/batch/TreeRootHolderRule.java
@@ -0,0 +1,61 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.batch;
+
+import java.util.Objects;
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+import org.sonar.server.computation.component.Component;
+import org.sonar.server.computation.component.TreeRootHolder;
+
+public class TreeRootHolderRule implements TestRule, TreeRootHolder {
+  private Component root;
+
+  @Override
+  public Statement apply(final Statement statement, Description description) {
+    return new Statement() {
+      @Override
+      public void evaluate() throws Throwable {
+        try {
+          statement.evaluate();
+        } finally {
+          clear();
+        }
+      }
+    };
+  }
+
+  private void clear() {
+    this.root = null;
+  }
+
+  @Override
+  public Component getRoot() {
+    if (root == null) {
+      throw new IllegalStateException("Root has not been set in " + TreeRootHolder.class.getSimpleName());
+    }
+    return root;
+  }
+
+  public void setRoot(Component newRoot) {
+    this.root = Objects.requireNonNull(newRoot);
+  }
+}
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/context/package-info.java b/server/sonar-server/src/test/java/org/sonar/server/computation/component/MutableTreeRootHolderRule.java
index d15e656106a..eaf2a512a65 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/context/package-info.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/component/MutableTreeRootHolderRule.java
@@ -17,8 +17,13 @@
  * along with this program; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
+package org.sonar.server.computation.component;
 
-@ParametersAreNonnullByDefault
-package org.sonar.server.computation.context;
+import org.sonar.server.computation.batch.TreeRootHolderRule;
 
-import javax.annotation.ParametersAreNonnullByDefault;
+public class MutableTreeRootHolderRule extends TreeRootHolderRule implements MutableTreeRootHolder {
+  @Override
+  public void setRoot(Component newRoot) {
+    super.setRoot(newRoot);
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/component/TreeRootHolderImplTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/component/TreeRootHolderImplTest.java
new file mode 100644
index 00000000000..1613b765545
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/component/TreeRootHolderImplTest.java
@@ -0,0 +1,47 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.component;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+public class TreeRootHolderImplTest {
+
+  TreeRootHolderImpl treeRootHolder = new TreeRootHolderImpl();
+  Component component = mock(Component.class);
+
+  @Test(expected = NullPointerException.class)
+  public void setRoot_throws_NPE_if_arg_is_null() {
+    treeRootHolder.setRoot(null);
+  }
+
+  @Test(expected = IllegalStateException.class)
+  public void getRoot_throws_ISE_if_root_has_not_been_set_yet() {
+    treeRootHolder.getRoot();
+  }
+
+  @Test
+  public void verify_setRoot_getRoot() {
+    treeRootHolder.setRoot(component);
+    assertThat(treeRootHolder.getRoot()).isSameAs(component);
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/step/BuildComponentTreeStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/step/BuildComponentTreeStepTest.java
new file mode 100644
index 00000000000..60eb895a58b
--- /dev/null
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/step/BuildComponentTreeStepTest.java
@@ -0,0 +1,121 @@
+/*
+ * SonarQube, open source software quality management tool.
+ * Copyright (C) 2008-2014 SonarSource
+ * mailto:contact AT sonarsource DOT com
+ *
+ * SonarQube is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * SonarQube is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.server.computation.step;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.sonar.batch.protocol.Constants;
+import org.sonar.batch.protocol.output.BatchReport;
+import org.sonar.batch.protocol.output.BatchReport.Metadata;
+import org.sonar.server.computation.ComputationContext;
+import org.sonar.server.computation.batch.BatchReportReaderRule;
+import org.sonar.server.computation.component.Component;
+import org.sonar.server.computation.component.MutableTreeRootHolderRule;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.sonar.batch.protocol.Constants.ComponentType.DIRECTORY;
+import static org.sonar.batch.protocol.Constants.ComponentType.FILE;
+import static org.sonar.batch.protocol.Constants.ComponentType.MODULE;
+import static org.sonar.batch.protocol.Constants.ComponentType.PROJECT;
+
+public class BuildComponentTreeStepTest {
+  private static final int ROOT_REF = 1;
+  private static final int MODULE_REF = 2;
+  private static final int DIR_REF_1 = 3;
+  private static final int FILE_1_REF = 4;
+  private static final int FILE_2_REF = 5;
+  private static final int DIR_REF_2 = 6;
+  private static final int FILE_3_REF = 7;
+
+  @Rule
+  public BatchReportReaderRule reportReader = new BatchReportReaderRule();
+  @Rule
+  public MutableTreeRootHolderRule treeRootHolder = new MutableTreeRootHolderRule();
+
+  private BuildComponentTreeStep underTest = new BuildComponentTreeStep(reportReader, treeRootHolder);
+
+  @Before
+  public void setUp() throws Exception {
+    reportReader.setMetadata(Metadata.newBuilder().setRootComponentRef(ROOT_REF).build());
+  }
+
+  @Test(expected = NullPointerException.class)
+  public void fails_if_root_component_does_not_exist_in_reportReader() {
+    underTest.execute(mock(ComputationContext.class));
+  }
+
+  @Test
+  public void verify_ref_and_type() {
+    for (Constants.ComponentType componentType : Constants.ComponentType.values()) {
+      int componentRef = 1;
+      reportReader.putComponent(component(componentRef, componentType));
+
+      underTest.execute(mock(ComputationContext.class));
+
+      Component root = treeRootHolder.getRoot();
+      assertThat(root).isNotNull();
+      assertThat(root.getType()).isEqualTo(Component.Type.valueOf(componentType.name()));
+      assertThat(root.getRef()).isEqualTo(ROOT_REF);
+      assertThat(root.getChildren()).isEmpty();
+    }
+  }
+
+  @Test
+  public void verify_tree_is_correctly_built() {
+    reportReader.putComponent(component(ROOT_REF, PROJECT, MODULE_REF));
+    reportReader.putComponent(component(MODULE_REF, MODULE, DIR_REF_1, DIR_REF_2));
+    reportReader.putComponent(component(DIR_REF_1, DIRECTORY, FILE_1_REF, FILE_2_REF));
+    reportReader.putComponent(component(FILE_1_REF, FILE));
+    reportReader.putComponent(component(FILE_2_REF, FILE));
+    reportReader.putComponent(component(DIR_REF_2, DIRECTORY, FILE_3_REF));
+    reportReader.putComponent(component(FILE_3_REF, FILE));
+
+    underTest.execute(mock(ComputationContext.class));
+
+    Component root = treeRootHolder.getRoot();
+    assertThat(root).isNotNull();
+    verifyComponent(root, Component.Type.PROJECT, ROOT_REF, 1);
+    Component module = root.getChildren().iterator().next();
+    verifyComponent(module, Component.Type.MODULE, MODULE_REF, 2);
+    Component dir1 = module.getChildren().get(0);
+    verifyComponent(dir1, Component.Type.DIRECTORY, DIR_REF_1, 2);
+    verifyComponent(dir1.getChildren().get(0), Component.Type.FILE, FILE_1_REF, 0);
+    verifyComponent(dir1.getChildren().get(1), Component.Type.FILE, FILE_2_REF, 0);
+    Component dir2 = module.getChildren().get(1);
+    verifyComponent(dir2, Component.Type.DIRECTORY, DIR_REF_2, 1);
+    verifyComponent(dir2.getChildren().iterator().next(), Component.Type.FILE, FILE_3_REF, 0);
+  }
+
+  private void verifyComponent(Component component, Component.Type type, int componentRef, int size) {
+    assertThat(component.getType()).isEqualTo(type);
+    assertThat(component.getRef()).isEqualTo(componentRef);
+    assertThat(component.getChildren()).hasSize(size);
+  }
+
+  private static BatchReport.Component component(int componentRef, Constants.ComponentType componentType, int... children) {
+    BatchReport.Component.Builder builder = BatchReport.Component.newBuilder().setType(componentType).setRef(componentRef);
+    for (int child : children) {
+      builder.addChildRef(child);
+    }
+    return builder.build();
+  }
+}
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/step/ParseReportStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/step/ParseReportStepTest.java
index abedf2cac87..9e1487fcf78 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/step/ParseReportStepTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/step/ParseReportStepTest.java
@@ -32,8 +32,8 @@ import org.sonar.batch.protocol.output.BatchReport;
 import org.sonar.core.persistence.DbTester;
 import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReaderRule;
+import org.sonar.server.computation.batch.TreeRootHolderRule;
 import org.sonar.server.computation.component.Component;
-import org.sonar.server.computation.component.ComponentTreeBuilders;
 import org.sonar.server.computation.component.DumbComponent;
 import org.sonar.server.computation.issue.IssueComputation;
 
@@ -53,12 +53,14 @@ public class ParseReportStepTest extends BaseStepTest {
   public TemporaryFolder temp = new TemporaryFolder();
   @Rule
   public BatchReportReaderRule reportReader = new BatchReportReaderRule();
+  @Rule
+  public TreeRootHolderRule treeRootHolder = new TreeRootHolderRule();
 
   @ClassRule
   public static DbTester dbTester = new DbTester();
 
   IssueComputation issueComputation = mock(IssueComputation.class);
-  ParseReportStep sut = new ParseReportStep(issueComputation, reportReader);
+  ParseReportStep sut = new ParseReportStep(issueComputation, reportReader, treeRootHolder);
 
   @Test
   public void extract_report_from_db_and_browse_components() throws Exception {
@@ -68,9 +70,9 @@ public class ParseReportStepTest extends BaseStepTest {
 
     generateReport();
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(root));
+    treeRootHolder.setRoot(root);
 
-    sut.execute(context);
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(reportReader.readMetadata().getRootComponentRef()).isEqualTo(1);
     assertThat(reportReader.readMetadata().getDeletedComponentsCount()).isEqualTo(1);
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistComponentsStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistComponentsStepTest.java
index 332114db14d..aadd795b9fa 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistComponentsStepTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistComponentsStepTest.java
@@ -35,14 +35,15 @@ import org.sonar.server.component.ComponentTesting;
 import org.sonar.server.component.db.ComponentDao;
 import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReaderRule;
+import org.sonar.server.computation.batch.TreeRootHolderRule;
 import org.sonar.server.computation.component.Component;
-import org.sonar.server.computation.component.ComponentTreeBuilders;
 import org.sonar.server.computation.component.DbComponentsRefCache;
 import org.sonar.server.computation.component.DumbComponent;
 import org.sonar.server.db.DbClient;
 import org.sonar.test.DbTests;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
 
 @Category(DbTests.class)
 public class PersistComponentsStepTest extends BaseStepTest {
@@ -53,6 +54,8 @@ public class PersistComponentsStepTest extends BaseStepTest {
   public static DbTester dbTester = new DbTester();
   @Rule
   public BatchReportReaderRule reportReader = new BatchReportReaderRule();
+  @Rule
+  public TreeRootHolderRule treeRootHolder = new TreeRootHolderRule();
 
   DbSession session;
   DbClient dbClient;
@@ -67,7 +70,7 @@ public class PersistComponentsStepTest extends BaseStepTest {
     dbClient = new DbClient(dbTester.database(), dbTester.myBatis(), new ComponentDao());
 
     dbComponentsRefCache = new DbComponentsRefCache();
-    sut = new PersistComponentsStep(dbClient, dbComponentsRefCache, reportReader);
+    sut = new PersistComponentsStep(dbClient, dbComponentsRefCache, reportReader, treeRootHolder);
   }
 
   @Override
@@ -116,12 +119,11 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setLanguage("java")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY",
         new DumbComponent(Component.Type.DIRECTORY, 3, "CDEF", "MODULE_KEY:src/main/java/dir",
-          new DumbComponent(Component.Type.FILE, 4, "DEFG", "MODULE_KEY:src/main/java/dir/Foo.java"))));
-    sut.execute(new ComputationContext(
-      ComponentTreeBuilders.from(root)));
+          new DumbComponent(Component.Type.FILE, 4, "DEFG", "MODULE_KEY:src/main/java/dir/Foo.java")))));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbTester.countRowsOfTable("projects")).isEqualTo(4);
 
@@ -209,10 +211,10 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setPath("pom.xml")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.DIRECTORY, 2, "CDEF", PROJECT_KEY + ":/",
-        new DumbComponent(Component.Type.FILE, 3, "DEFG", PROJECT_KEY + ":pom.xml")));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+        new DumbComponent(Component.Type.FILE, 3, "DEFG", PROJECT_KEY + ":pom.xml"))));
+    sut.execute(mock(ComputationContext.class));
 
     ComponentDto directory = dbClient.componentDao().selectNullableByKey(session, "PROJECT_KEY:/");
     assertThat(directory).isNotNull();
@@ -251,10 +253,10 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setIsTest(true)
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.DIRECTORY, 2, "CDEF", PROJECT_KEY + ":src/test/java/dir",
-        new DumbComponent(Component.Type.FILE, 3, "DEFG", PROJECT_KEY + ":src/test/java/dir/FooTest.java")));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+        new DumbComponent(Component.Type.FILE, 3, "DEFG", PROJECT_KEY + ":src/test/java/dir/FooTest.java"))));
+    sut.execute(mock(ComputationContext.class));
 
     ComponentDto file = dbClient.componentDao().selectNullableByKey(session, PROJECT_KEY + ":src/test/java/dir/FooTest.java");
     assertThat(file).isNotNull();
@@ -285,29 +287,29 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .addChildRef(2)
       .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(2)
-      .setType(Constants.ComponentType.MODULE)
-      .setKey("MODULE_KEY")
-      .setName("Module")
-      .addChildRef(3)
-      .build());
+        .setRef(2)
+        .setType(Constants.ComponentType.MODULE)
+        .setKey("MODULE_KEY")
+        .setName("Module")
+        .addChildRef(3)
+        .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(3)
-      .setType(Constants.ComponentType.DIRECTORY)
-      .setPath("src/main/java/dir")
-      .addChildRef(4)
-      .build());
+        .setRef(3)
+        .setType(Constants.ComponentType.DIRECTORY)
+        .setPath("src/main/java/dir")
+        .addChildRef(4)
+        .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(4)
-      .setType(Constants.ComponentType.FILE)
-      .setPath("src/main/java/dir/Foo.java")
-      .build());
+        .setRef(4)
+        .setType(Constants.ComponentType.FILE)
+        .setPath("src/main/java/dir/Foo.java")
+        .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY",
         new DumbComponent(Component.Type.DIRECTORY, 3, "CDEF", "MODULE_KEY:src/main/java/dir",
-          new DumbComponent(Component.Type.FILE, 4, "DEFG", "MODULE_KEY:src/main/java/dir/Foo.java"))));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+          new DumbComponent(Component.Type.FILE, 4, "DEFG", "MODULE_KEY:src/main/java/dir/Foo.java")))));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbTester.countRowsOfTable("projects")).isEqualTo(4);
 
@@ -378,12 +380,12 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setPath("src/main/java/dir")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY",
         new DumbComponent(Component.Type.MODULE, 3, "CDEF", "SUB_MODULE_1_KEY",
           new DumbComponent(Component.Type.MODULE, 4, "DEFG", "SUB_MODULE_2_KEY",
-            new DumbComponent(Component.Type.DIRECTORY, 5, "EFGH", "SUB_MODULE_2_KEY:src/main/java/dir")))));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+            new DumbComponent(Component.Type.DIRECTORY, 5, "EFGH", "SUB_MODULE_2_KEY:src/main/java/dir"))))));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbTester.countRowsOfTable("projects")).isEqualTo(5);
 
@@ -442,11 +444,11 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setName("Module B")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_A",
         new DumbComponent(Component.Type.MODULE, 3, "DEFG", "SUB_MODULE_A")),
-      new DumbComponent(Component.Type.MODULE, 4, "CDEF", "MODULE_B"));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+      new DumbComponent(Component.Type.MODULE, 4, "CDEF", "MODULE_B")));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbTester.countRowsOfTable("projects")).isEqualTo(4);
 
@@ -487,16 +489,16 @@ public class PersistComponentsStepTest extends BaseStepTest {
     session.commit();
 
     reportReader.setMetadata(BatchReport.Metadata.newBuilder()
-      .setRootComponentRef(1)
-      .build());
+        .setRootComponentRef(1)
+        .build());
 
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(1)
-      .setType(Constants.ComponentType.PROJECT)
-      .setKey(PROJECT_KEY)
-      .setName("Project")
-      .addChildRef(2)
-      .build());
+        .setRef(1)
+        .setType(Constants.ComponentType.PROJECT)
+        .setKey(PROJECT_KEY)
+        .setName("Project")
+        .addChildRef(2)
+        .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
       .setRef(2)
       .setType(Constants.ComponentType.MODULE)
@@ -505,22 +507,22 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .addChildRef(3)
       .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(3)
-      .setType(Constants.ComponentType.DIRECTORY)
-      .setPath("src/main/java/dir")
-      .addChildRef(4)
-      .build());
+        .setRef(3)
+        .setType(Constants.ComponentType.DIRECTORY)
+        .setPath("src/main/java/dir")
+        .addChildRef(4)
+        .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(4)
-      .setType(Constants.ComponentType.FILE)
-      .setPath("src/main/java/dir/Foo.java")
-      .build());
+        .setRef(4)
+        .setType(Constants.ComponentType.FILE)
+        .setPath("src/main/java/dir/Foo.java")
+        .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY",
         new DumbComponent(Component.Type.DIRECTORY, 3, "CDEF", "MODULE_KEY:src/main/java/dir",
-          new DumbComponent(Component.Type.FILE, 4, "DEFG", "MODULE_KEY:src/main/java/dir/Foo.java"))));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+          new DumbComponent(Component.Type.FILE, 4, "DEFG", "MODULE_KEY:src/main/java/dir/Foo.java")))));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbTester.countRowsOfTable("projects")).isEqualTo(4);
     assertThat(dbClient.componentDao().selectNullableByKey(session, PROJECT_KEY).getId()).isEqualTo(project.getId());
@@ -574,27 +576,27 @@ public class PersistComponentsStepTest extends BaseStepTest {
     session.commit();
 
     reportReader.setMetadata(BatchReport.Metadata.newBuilder()
-      .setRootComponentRef(1)
-      .build());
+        .setRootComponentRef(1)
+        .build());
 
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(1)
-      .setType(Constants.ComponentType.PROJECT)
-      .setKey(PROJECT_KEY)
-      .setName("New project name")
-      .addChildRef(2)
-      .build());
+        .setRef(1)
+        .setType(Constants.ComponentType.PROJECT)
+        .setKey(PROJECT_KEY)
+        .setName("New project name")
+        .addChildRef(2)
+        .build());
     reportReader.putComponent(BatchReport.Component.newBuilder()
-      .setRef(2)
-      .setType(Constants.ComponentType.MODULE)
-      .setKey("MODULE_KEY")
-      .setName("New module name")
-      .setPath("New path")
-      .build());
+        .setRef(2)
+        .setType(Constants.ComponentType.MODULE)
+        .setKey("MODULE_KEY")
+        .setName("New module name")
+        .setPath("New path")
+        .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
-      new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY"));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+      new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY")));
+    sut.execute(mock(ComputationContext.class));
 
     ComponentDto projectReloaded = dbClient.componentDao().selectNullableByKey(session, PROJECT_KEY);
     assertThat(projectReloaded.name()).isEqualTo("New project name");
@@ -631,9 +633,9 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setDescription("New module description")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
-      new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY"));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+      new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY")));
+    sut.execute(mock(ComputationContext.class));
 
     ComponentDto projectReloaded = dbClient.componentDao().selectNullableByKey(session, PROJECT_KEY);
     assertThat(projectReloaded.description()).isEqualTo("New project description");
@@ -669,9 +671,9 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setPath("New path")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
-      new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY"));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+      new DumbComponent(Component.Type.MODULE, 2, "BCDE", "MODULE_KEY")));
+    sut.execute(mock(ComputationContext.class));
 
     ComponentDto moduleReloaded = dbClient.componentDao().selectNullableByKey(session, "MODULE_KEY");
     assertThat(moduleReloaded.path()).isEqualTo("New path");
@@ -727,12 +729,12 @@ public class PersistComponentsStepTest extends BaseStepTest {
       .setPath("src/main/java/dir/Foo.java")
       .build());
 
-    DumbComponent root = new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "ABCD", PROJECT_KEY,
       new DumbComponent(Component.Type.MODULE, 2, "EDCB", "MODULE_A",
         new DumbComponent(Component.Type.MODULE, 3, "BCDE", "MODULE_B",
           new DumbComponent(Component.Type.DIRECTORY, 4, "CDEF", "MODULE_B:src/main/java/dir",
-            new DumbComponent(Component.Type.FILE, 5, "DEFG", "MODULE_B:src/main/java/dir/Foo.java")))));
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+            new DumbComponent(Component.Type.FILE, 5, "DEFG", "MODULE_B:src/main/java/dir/Foo.java"))))));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbTester.countRowsOfTable("projects")).isEqualTo(5);
 
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistTestsStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistTestsStepTest.java
index 9b274c7ac05..66f396d6622 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistTestsStepTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/step/PersistTestsStepTest.java
@@ -39,8 +39,8 @@ import org.sonar.core.persistence.MyBatis;
 import org.sonar.core.source.db.FileSourceDto;
 import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReaderRule;
+import org.sonar.server.computation.batch.TreeRootHolderRule;
 import org.sonar.server.computation.component.Component;
-import org.sonar.server.computation.component.ComponentTreeBuilders;
 import org.sonar.server.computation.component.DbComponentsRefCache;
 import org.sonar.server.computation.component.DbComponentsRefCache.DbComponent;
 import org.sonar.server.computation.component.DumbComponent;
@@ -69,10 +69,10 @@ public class PersistTestsStepTest extends BaseStepTest {
 
   @ClassRule
   public static DbTester db = new DbTester();
-
   @Rule
   public BatchReportReaderRule reportReader = new BatchReportReaderRule();
-
+  @Rule
+  public TreeRootHolderRule treeRootHolder = new TreeRootHolderRule();
   @Rule
   public LogTester log = new LogTester();
 
@@ -95,7 +95,7 @@ public class PersistTestsStepTest extends BaseStepTest {
     when(system2.now()).thenReturn(now);
 
     dbComponentsRefCache = new DbComponentsRefCache();
-    sut = new PersistTestsStep(dbClient, system2, dbComponentsRefCache, reportReader);
+    sut = new PersistTestsStep(dbClient, system2, dbComponentsRefCache, reportReader, treeRootHolder);
 
     initBasicReport();
 
@@ -106,6 +106,7 @@ public class PersistTestsStepTest extends BaseStepTest {
         new DumbComponent(Component.Type.FILE, 5, MAIN_FILE_UUID_1, "MAIN_FILE1_KEY"),
         new DumbComponent(Component.Type.FILE, 6, MAIN_FILE_UUID_2, "MAIN_FILE2_KEY")
       ));
+    treeRootHolder.setRoot(root);
   }
 
   @After
@@ -120,7 +121,7 @@ public class PersistTestsStepTest extends BaseStepTest {
 
   @Test
   public void no_test_in_database_and_batch_report() {
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(dbClient.fileSourceDao().selectTest(TEST_FILE_UUID_1)).isNull();
     assertThat(log.logs()).isEmpty();
@@ -137,7 +138,7 @@ public class PersistTestsStepTest extends BaseStepTest {
       );
     reportReader.putCoverageDetails(TEST_FILE_REF_1, coverageDetails);
 
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(db.countRowsOfTable("file_sources")).isEqualTo(1);
 
@@ -160,7 +161,7 @@ public class PersistTestsStepTest extends BaseStepTest {
     reportReader.putTests(TEST_FILE_REF_1, Arrays.asList(newTest(1)));
     reportReader.putCoverageDetails(TEST_FILE_REF_1, Arrays.asList(newCoverageDetail(1, MAIN_FILE_REF_1)));
 
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     FileSourceDto dto = dbClient.fileSourceDao().selectTest(TEST_FILE_UUID_1);
     assertThat(dto.getCreatedAt()).isEqualTo(now);
@@ -186,7 +187,7 @@ public class PersistTestsStepTest extends BaseStepTest {
     List<BatchReport.Test> batchTests = Arrays.asList(newTest(1));
     reportReader.putTests(TEST_FILE_REF_1, batchTests);
 
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     FileSourceDto dto = dbClient.fileSourceDao().selectTest(TEST_FILE_UUID_1);
     assertThat(dto.getFileUuid()).isEqualTo(TEST_FILE_UUID_1);
@@ -204,7 +205,7 @@ public class PersistTestsStepTest extends BaseStepTest {
     reportReader.putCoverageDetails(TEST_FILE_REF_1, coverageDetails);
     reportReader.putCoverageDetails(TEST_FILE_REF_2, coverageDetails);
 
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     assertThat(log.logs(LoggerLevel.WARN)).hasSize(1);
     assertThat(log.logs(LoggerLevel.WARN).get(0)).isEqualTo("Some coverage tests are not taken into account during analysis of project 'PROJECT_KEY'");
@@ -221,7 +222,7 @@ public class PersistTestsStepTest extends BaseStepTest {
         newCoverageDetailWithLines(1, MAIN_FILE_REF_1, 1, 3),
         newCoverageDetailWithLines(1, MAIN_FILE_REF_1, 2, 4)));
 
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     FileSourceDto dto = dbClient.fileSourceDao().selectTest(TEST_FILE_UUID_1);
     List<Integer> coveredLines = dto.getTestData().get(0).getCoveredFile(0).getCoveredLineList();
@@ -254,7 +255,7 @@ public class PersistTestsStepTest extends BaseStepTest {
     reportReader.putCoverageDetails(TEST_FILE_REF_1, Arrays.asList(newCoverageDetail));
 
     // ACT
-    sut.execute(new ComputationContext(ComponentTreeBuilders.from(root)));
+    sut.execute(mock(ComputationContext.class));
 
     // ASSERT
     FileSourceDto dto = dbClient.fileSourceDao().selectTest(TEST_FILE_UUID_1);
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStepTest.java
index c91f974c6ce..5196d77db7d 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStepTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/step/PopulateComponentsUuidAndKeyStepTest.java
@@ -38,12 +38,14 @@ import org.sonar.server.component.ComponentTesting;
 import org.sonar.server.component.db.ComponentDao;
 import org.sonar.server.computation.ComputationContext;
 import org.sonar.server.computation.batch.BatchReportReaderRule;
+import org.sonar.server.computation.batch.TreeRootHolderRule;
 import org.sonar.server.computation.component.Component;
 import org.sonar.server.computation.component.ComponentTreeBuilders;
 import org.sonar.server.db.DbClient;
 import org.sonar.test.DbTests;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
 
 @Category(DbTests.class)
 public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
@@ -54,6 +56,8 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
   public static DbTester dbTester = new DbTester();
   @Rule
   public BatchReportReaderRule reportReader = new BatchReportReaderRule();
+  @Rule
+  public TreeRootHolderRule treeRootHolder = new TreeRootHolderRule();
 
   DbClient dbClient;
   DbSession session;
@@ -66,7 +70,7 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
     session = dbTester.myBatis().openSession(false);
     dbClient = new DbClient(dbTester.database(), dbTester.myBatis(), new ComponentDao());
 
-    sut = new PopulateComponentsUuidAndKeyStep(dbClient, reportReader);
+    sut = new PopulateComponentsUuidAndKeyStep(dbClient, reportReader, treeRootHolder);
   }
 
   @After
@@ -109,10 +113,10 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
       .setPath("src/main/java/dir/Foo.java")
       .build());
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(reportReader));
-    sut.execute(context);
+    treeRootHolder.setRoot(ComponentTreeBuilders.from(reportReader).build());
+    sut.execute(mock(ComputationContext.class));
 
-    Map<Integer, Component> componentsByRef = getComponentsByRef(context.getRoot());
+    Map<Integer, Component> componentsByRef = getComponentsByRef(treeRootHolder.getRoot());
 
     assertThat(componentsByRef.get(1).getKey()).isEqualTo(PROJECT_KEY);
     assertThat(componentsByRef.get(1).getUuid()).isNotNull();
@@ -166,10 +170,11 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
       .setPath("src/main/java/dir/Foo.java")
       .build());
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(reportReader));
-    sut.execute(context);
 
-    Map<Integer, Component> componentsByRef = getComponentsByRef(context.getRoot());
+    treeRootHolder.setRoot(ComponentTreeBuilders.from(reportReader).build());
+    sut.execute(mock(ComputationContext.class));
+
+    Map<Integer, Component> componentsByRef = getComponentsByRef(treeRootHolder.getRoot());
 
     assertThat(componentsByRef.get(1).getKey()).isEqualTo(PROJECT_KEY);
     assertThat(componentsByRef.get(1).getUuid()).isEqualTo("ABCD");
@@ -223,10 +228,10 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
       .setPath("src/main/java/dir/Foo.java")
       .build());
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(reportReader));
-    sut.execute(context);
+    treeRootHolder.setRoot(ComponentTreeBuilders.from(reportReader).build());
+    sut.execute(mock(ComputationContext.class));
 
-    Map<Integer, Component> componentsByRef = getComponentsByRef(context.getRoot());
+    Map<Integer, Component> componentsByRef = getComponentsByRef(treeRootHolder.getRoot());
 
     assertThat(componentsByRef.get(4).getKey()).isEqualTo("SUB_MODULE_KEY:src/main/java/dir");
     assertThat(componentsByRef.get(5).getKey()).isEqualTo("SUB_MODULE_KEY:src/main/java/dir/Foo.java");
@@ -266,10 +271,10 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
       .setPath("src/main/java/dir/Foo.java")
       .build());
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(reportReader));
-    sut.execute(context);
+    treeRootHolder.setRoot(ComponentTreeBuilders.from(reportReader).build());
+    sut.execute(mock(ComputationContext.class));
 
-    Map<Integer, Component> componentsByRef = getComponentsByRef(context.getRoot());
+    Map<Integer, Component> componentsByRef = getComponentsByRef(treeRootHolder.getRoot());
 
     assertThat(componentsByRef.get(1).getKey()).isEqualTo("PROJECT_KEY:origin/master");
     assertThat(componentsByRef.get(2).getKey()).isEqualTo("MODULE_KEY:origin/master");
@@ -319,10 +324,10 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
       .setPath("pom.xml")
       .build());
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(reportReader));
-    sut.execute(context);
+    treeRootHolder.setRoot(ComponentTreeBuilders.from(reportReader).build());
+    sut.execute(mock(ComputationContext.class));
 
-    Map<Integer, Component> componentsByRef = getComponentsByRef(context.getRoot());
+    Map<Integer, Component> componentsByRef = getComponentsByRef(treeRootHolder.getRoot());
 
     assertThat(componentsByRef.get(1).getKey()).isEqualTo(PROJECT_KEY);
     assertThat(componentsByRef.get(1).getUuid()).isNotNull();
@@ -379,10 +384,10 @@ public class PopulateComponentsUuidAndKeyStepTest extends BaseStepTest {
       .setPath("src/main/java/dir/Foo.java")
       .build());
 
-    ComputationContext context = new ComputationContext(ComponentTreeBuilders.from(reportReader));
-    sut.execute(context);
+    treeRootHolder.setRoot(ComponentTreeBuilders.from(reportReader).build());
+    sut.execute(mock(ComputationContext.class));
 
-    Map<Integer, Component> componentsByRef = getComponentsByRef(context.getRoot());
+    Map<Integer, Component> componentsByRef = getComponentsByRef(treeRootHolder.getRoot());
 
     assertThat(componentsByRef.get(1).getKey()).isEqualTo(PROJECT_KEY);
     assertThat(componentsByRef.get(1).getUuid()).isNotNull();
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/step/QualityProfileEventsStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/step/QualityProfileEventsStepTest.java
index 201a6f85e80..1a54ad06338 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/step/QualityProfileEventsStepTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/step/QualityProfileEventsStepTest.java
@@ -27,6 +27,8 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import javax.annotation.Nullable;
+import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.invocation.InvocationOnMock;
@@ -38,8 +40,8 @@ import org.sonar.batch.protocol.output.BatchReport;
 import org.sonar.core.UtcDateUtils;
 import org.sonar.core.measure.db.MeasureDto;
 import org.sonar.server.computation.ComputationContext;
+import org.sonar.server.computation.batch.TreeRootHolderRule;
 import org.sonar.server.computation.component.Component;
-import org.sonar.server.computation.component.ComponentTreeBuilder;
 import org.sonar.server.computation.component.DumbComponent;
 import org.sonar.server.computation.event.Event;
 import org.sonar.server.computation.event.EventRepository;
@@ -61,6 +63,8 @@ import static org.mockito.Mockito.when;
 import static org.sonar.api.utils.DateUtils.parseDateTime;
 
 public class QualityProfileEventsStepTest {
+  @Rule
+  public TreeRootHolderRule treeRootHolder = new TreeRootHolderRule();
 
   private static final String QP_NAME_1 = "qp_1";
   private static final String QP_NAME_2 = "qp_2";
@@ -73,36 +77,35 @@ public class QualityProfileEventsStepTest {
   private EventRepository eventRepository = mock(EventRepository.class);
   private ArgumentCaptor<Event> eventArgumentCaptor = ArgumentCaptor.forClass(Event.class);
 
-  private QualityProfileEventsStep underTest = new QualityProfileEventsStep(measureRepository, eventRepository, languageRepository);
+  private QualityProfileEventsStep underTest = new QualityProfileEventsStep(treeRootHolder, measureRepository, eventRepository, languageRepository);
+
+  @Before
+  public void setUp() throws Exception {
+    treeRootHolder.setRoot(new DumbComponent(Component.Type.PROJECT, 1, "uuid", "key"));
+  }
 
   @Test
   public void no_effect_if_no_previous_measure() {
-    ComputationContext context = newNoChildRootContext();
-
-    when(measureRepository.findPrevious(context.getRoot(), CoreMetrics.QUALITY_PROFILES)).thenReturn(Optional.<MeasureDto>absent());
+    when(measureRepository.findPrevious(treeRootHolder.getRoot(), CoreMetrics.QUALITY_PROFILES)).thenReturn(Optional.<MeasureDto>absent());
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
     verifyNoMoreInteractions(eventRepository);
   }
 
   @Test(expected = IllegalStateException.class)
   public void ISE_if_no_current_measure() {
-    ComputationContext context = newNoChildRootContext();
+    when(measureRepository.findPrevious(treeRootHolder.getRoot(), CoreMetrics.QUALITY_PROFILES)).thenReturn(Optional.of(newMeasureDto()));
+    when(measureRepository.findCurrent(treeRootHolder.getRoot(), CoreMetrics.QUALITY_PROFILES)).thenReturn(Optional.<BatchReport.Measure>absent());
 
-    when(measureRepository.findPrevious(context.getRoot(), CoreMetrics.QUALITY_PROFILES)).thenReturn(Optional.of(newMeasureDto()));
-    when(measureRepository.findCurrent(context.getRoot(), CoreMetrics.QUALITY_PROFILES)).thenReturn(Optional.<BatchReport.Measure>absent());
-
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
   }
 
   @Test
   public void no_event_if_no_qp_now_nor_before() {
-    ComputationContext context = newNoChildRootContext();
-
-    mockMeasures(context.getRoot(), null, null);
+    mockMeasures(treeRootHolder.getRoot(), null, null);
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
     verifyNoMoreInteractions(eventRepository);
   }
@@ -110,14 +113,13 @@ public class QualityProfileEventsStepTest {
   @Test
   public void added_event_if_one_new_qp() {
     QualityProfile qp = qp(QP_NAME_1, LANGUAGE_KEY_1);
-    ComputationContext context = newNoChildRootContext();
 
     Language language = mockLanguageInRepository(LANGUAGE_KEY_1);
-    mockMeasures(context.getRoot(), null, arrayOf(qp));
+    mockMeasures(treeRootHolder.getRoot(), null, arrayOf(qp));
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
-    verify(eventRepository).add(eq(context.getRoot()), eventArgumentCaptor.capture());
+    verify(eventRepository).add(eq(treeRootHolder.getRoot()), eventArgumentCaptor.capture());
     verifyNoMoreInteractions(eventRepository);
     verifyEvent(eventArgumentCaptor.getValue(), "Use '" + qp.getQpName() + "' (" + language.getName() + ")", null);
   }
@@ -125,14 +127,13 @@ public class QualityProfileEventsStepTest {
   @Test
   public void added_event_uses_language_key_in_message_if_language_not_found() {
     QualityProfile qp = qp(QP_NAME_1, LANGUAGE_KEY_1);
-    ComputationContext context = newNoChildRootContext();
 
     mockLanguageNotInRepository(LANGUAGE_KEY_1);
-    mockMeasures(context.getRoot(), null, arrayOf(qp));
+    mockMeasures(treeRootHolder.getRoot(), null, arrayOf(qp));
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
-    verify(eventRepository).add(eq(context.getRoot()), eventArgumentCaptor.capture());
+    verify(eventRepository).add(eq(treeRootHolder.getRoot()), eventArgumentCaptor.capture());
     verifyNoMoreInteractions(eventRepository);
     verifyEvent(eventArgumentCaptor.getValue(), "Use '" + qp.getQpName() + "' (" + qp.getLanguageKey() + ")", null);
   }
@@ -140,14 +141,13 @@ public class QualityProfileEventsStepTest {
   @Test
   public void no_more_used_event_if_qp_no_more_listed() {
     QualityProfile qp = qp(QP_NAME_1, LANGUAGE_KEY_1);
-    ComputationContext context = newNoChildRootContext();
 
-    mockMeasures(context.getRoot(), arrayOf(qp), null);
+    mockMeasures(treeRootHolder.getRoot(), arrayOf(qp), null);
     Language language = mockLanguageInRepository(LANGUAGE_KEY_1);
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
-    verify(eventRepository).add(eq(context.getRoot()), eventArgumentCaptor.capture());
+    verify(eventRepository).add(eq(treeRootHolder.getRoot()), eventArgumentCaptor.capture());
     verifyNoMoreInteractions(eventRepository);
     verifyEvent(eventArgumentCaptor.getValue(), "Stop using '" + qp.getQpName() + "' (" + language.getName() + ")", null);
   }
@@ -155,14 +155,13 @@ public class QualityProfileEventsStepTest {
   @Test
   public void no_more_used_event_uses_language_key_in_message_if_language_not_found() {
     QualityProfile qp = qp(QP_NAME_1, LANGUAGE_KEY_1);
-    ComputationContext context = newNoChildRootContext();
 
-    mockMeasures(context.getRoot(), arrayOf(qp), null);
+    mockMeasures(treeRootHolder.getRoot(), arrayOf(qp), null);
     mockLanguageNotInRepository(LANGUAGE_KEY_1);
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
-    verify(eventRepository).add(eq(context.getRoot()), eventArgumentCaptor.capture());
+    verify(eventRepository).add(eq(treeRootHolder.getRoot()), eventArgumentCaptor.capture());
     verifyNoMoreInteractions(eventRepository);
     verifyEvent(eventArgumentCaptor.getValue(), "Stop using '" + qp.getQpName() + "' (" + qp.getLanguageKey() + ")", null);
   }
@@ -170,11 +169,10 @@ public class QualityProfileEventsStepTest {
   @Test
   public void no_event_if_same_qp_with_same_date() {
     QualityProfile qp = qp(QP_NAME_1, LANGUAGE_KEY_1);
-    ComputationContext context = newNoChildRootContext();
 
-    mockMeasures(context.getRoot(), arrayOf(qp), arrayOf(qp));
+    mockMeasures(treeRootHolder.getRoot(), arrayOf(qp), arrayOf(qp));
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
     verify(eventRepository, never()).add(any(Component.class), any(Event.class));
   }
@@ -183,14 +181,13 @@ public class QualityProfileEventsStepTest {
   public void changed_event_if_same_qp_but_no_same_date() {
     QualityProfile qp1 = qp(QP_NAME_1, LANGUAGE_KEY_1, parseDateTime("2011-04-25T01:05:13+0100"));
     QualityProfile qp2 = qp(QP_NAME_1, LANGUAGE_KEY_1, parseDateTime("2011-04-25T01:05:17+0100"));
-    ComputationContext context = newNoChildRootContext();
 
-    mockMeasures(context.getRoot(), arrayOf(qp1), arrayOf(qp2));
+    mockMeasures(treeRootHolder.getRoot(), arrayOf(qp1), arrayOf(qp2));
     Language language = mockLanguageInRepository(LANGUAGE_KEY_1);
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
-    verify(eventRepository).add(eq(context.getRoot()), eventArgumentCaptor.capture());
+    verify(eventRepository).add(eq(treeRootHolder.getRoot()), eventArgumentCaptor.capture());
     verifyNoMoreInteractions(eventRepository);
     verifyEvent(eventArgumentCaptor.getValue(),
       "Changes in '" + qp2.getQpName() + "' (" + language.getName() + ")",
@@ -200,7 +197,6 @@ public class QualityProfileEventsStepTest {
 
   @Test
   public void verify_detection_with_complex_mix_of_qps() {
-    ComputationContext context = newNoChildRootContext();
     final Set<Event> events = new HashSet<>();
     doAnswer(new Answer() {
       @Override
@@ -208,10 +204,10 @@ public class QualityProfileEventsStepTest {
         events.add((Event) invocationOnMock.getArguments()[1]);
         return null;
       }
-    }).when(eventRepository).add(eq(context.getRoot()), any(Event.class));
+    }).when(eventRepository).add(eq(treeRootHolder.getRoot()), any(Event.class));
 
     mockMeasures(
-      context.getRoot(), arrayOf(
+      treeRootHolder.getRoot(), arrayOf(
         qp(QP_NAME_2, LANGUAGE_KEY_1),
         qp(QP_NAME_2, LANGUAGE_KEY_2),
         qp(QP_NAME_1, LANGUAGE_KEY_1, parseDateTime("2011-04-25T01:05:13+0100"))
@@ -223,7 +219,7 @@ public class QualityProfileEventsStepTest {
       ));
     mockNoLanguageInRepository();
 
-    underTest.execute(context);
+    underTest.execute(mock(ComputationContext.class));
 
     assertThat(events).extracting("name").containsOnly(
       "Stop using '" + QP_NAME_2 + "' (" + LANGUAGE_KEY_1 + ")",
@@ -292,13 +288,4 @@ public class QualityProfileEventsStepTest {
     return QPMeasureData.toJson(new QPMeasureData(qualityProfiles));
   }
 
-  private ComputationContext newNoChildRootContext() {
-    return new ComputationContext(new ComponentTreeBuilder() {
-      @Override
-      public Component build() {
-        return new DumbComponent(Component.Type.PROJECT, 1, "uuid", "key");
-      }
-    });
-  }
-
 }