Improve SQ code quality

11 files changed, 95 insertions, 101 deletions

diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImpl.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImpl.java
index 33a36e45fa4..b308a595066 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImpl.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImpl.java
@@ -19,19 +19,16 @@
  */
 package org.sonar.ce.task.projectanalysis.language;
 
-import com.google.common.base.Function;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
-import javax.annotation.Nonnull;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import org.sonar.api.resources.Language;
 import org.springframework.beans.factory.annotation.Autowired;
 
-import static com.google.common.base.Predicates.notNull;
-import static com.google.common.collect.Iterables.filter;
-import static com.google.common.collect.Maps.uniqueIndex;
-import static java.util.Arrays.asList;
-
 /**
  * Implementation of {@link LanguageRepository} which find {@link Language} instances available in the container.
  */
@@ -46,20 +43,11 @@ public class LanguageRepositoryImpl implements LanguageRepository {
 
   @Autowired(required = false)
   public LanguageRepositoryImpl(Language... languages) {
-    this.languagesByKey = uniqueIndex(filter(asList(languages), notNull()), LanguageToKey.INSTANCE);
+    this.languagesByKey = Arrays.stream(languages).filter(Objects::nonNull).collect(Collectors.toMap(Language::getKey, Function.identity()));
   }
 
   @Override
   public Optional<Language> find(String languageKey) {
     return Optional.ofNullable(languagesByKey.get(languageKey));
   }
-
-  private enum LanguageToKey implements Function<Language, String> {
-    INSTANCE;
-
-    @Override
-    public String apply(@Nonnull Language input) {
-      return input.getKey();
-    }
-  }
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/LoadMeasureComputersStep.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/LoadMeasureComputersStep.java
index ee8d604da2d..6cbff6ad88c 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/LoadMeasureComputersStep.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/LoadMeasureComputersStep.java
@@ -19,18 +19,17 @@
  */
 package org.sonar.ce.task.projectanalysis.step;
 
-import com.google.common.base.Function;
-import com.google.common.base.Predicate;
-import com.google.common.base.Predicates;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import org.sonar.api.ce.measure.MeasureComputer;
 import org.sonar.api.measures.CoreMetrics;
 import org.sonar.api.measures.Metric;
@@ -48,9 +47,8 @@ import static org.sonar.api.ce.measure.MeasureComputer.MeasureComputerDefinition
 
 public class LoadMeasureComputersStep implements ComputationStep {
 
-  private static final Set<String> CORE_METRIC_KEYS = from(CoreMetrics.getMetrics()).transform(MetricToKey.INSTANCE).toSet();
-  private Set<String> pluginMetricKeys;
-
+  private static final Set<String> CORE_METRIC_KEYS = CoreMetrics.getMetrics().stream().map(Metric::getKey).collect(Collectors.toSet());
+  private final Set<String> pluginMetricKeys;
   private final MutableMeasureComputersHolder measureComputersHolder;
   private final MeasureComputer[] measureComputers;
 
@@ -58,10 +56,10 @@ public class LoadMeasureComputersStep implements ComputationStep {
   public LoadMeasureComputersStep(MutableMeasureComputersHolder measureComputersHolder, Metrics[] metricsRepositories, MeasureComputer[] measureComputers) {
     this.measureComputersHolder = measureComputersHolder;
     this.measureComputers = measureComputers;
-    this.pluginMetricKeys = from(Arrays.asList(metricsRepositories))
-      .transformAndConcat(MetricsToMetricList.INSTANCE)
-      .transform(MetricToKey.INSTANCE)
-      .toSet();
+    this.pluginMetricKeys = Arrays.stream(metricsRepositories)
+      .flatMap(m -> m.getMetrics().stream())
+      .map(Metric::getKey)
+      .collect(Collectors.toSet());
   }
 
   /**
@@ -89,8 +87,8 @@ public class LoadMeasureComputersStep implements ComputationStep {
   }
 
   @Override
-  public void execute(ComputationStep.Context context) {
-    List<MeasureComputerWrapper> wrappers = from(Arrays.asList(measureComputers)).transform(ToMeasureWrapper.INSTANCE).toList();
+  public void execute(Context context) {
+    List<MeasureComputerWrapper> wrappers = Arrays.stream(measureComputers).map(ToMeasureWrapper.INSTANCE).collect(Collectors.toList());
     validateMetrics(wrappers);
     measureComputersHolder.setMeasureComputers(sortComputers(wrappers));
   }
@@ -128,18 +126,24 @@ public class LoadMeasureComputersStep implements ComputationStep {
   }
 
   private void validateMetrics(List<MeasureComputerWrapper> wrappers) {
-    from(wrappers).transformAndConcat(ToInputMetrics.INSTANCE).filter(new ValidateInputMetric()).size();
-    from(wrappers).transformAndConcat(ToOutputMetrics.INSTANCE).filter(new ValidateOutputMetric()).size();
-    from(wrappers).filter(new ValidateUniqueOutputMetric()).size();
+    wrappers.stream().flatMap(s -> ToInputMetrics.INSTANCE.apply(s).stream()).forEach(this::validateInputMetric);
+    wrappers.stream().flatMap(s -> ToOutputMetrics.INSTANCE.apply(s).stream()).forEach(this::validateOutputMetric);
+    ValidateUniqueOutputMetric validateUniqueOutputMetric = new ValidateUniqueOutputMetric();
+    wrappers.forEach(validateUniqueOutputMetric::validate);
   }
 
-  private static Iterable<MeasureComputerWrapper> getDependencies(MeasureComputerWrapper measureComputer, ToComputerByKey toComputerByOutputMetricKey) {
+  private static Collection<MeasureComputerWrapper> getDependencies(MeasureComputerWrapper measureComputer, ToComputerByKey toComputerByOutputMetricKey) {
     // Remove null computer because a computer can depend on a metric that is only generated by a sensor or on a core metrics
-    return from(measureComputer.getDefinition().getInputMetrics()).transform(toComputerByOutputMetricKey).filter(Predicates.notNull());
+    return measureComputer.getDefinition().getInputMetrics().stream()
+      .map(toComputerByOutputMetricKey)
+      .filter(Objects::nonNull)
+      .collect(Collectors.toList());
   }
 
-  private static Iterable<MeasureComputerWrapper> getDependents(MeasureComputerWrapper measureComputer, ToComputerByKey toComputerByInputMetricKey) {
-    return from(measureComputer.getDefinition().getInputMetrics()).transform(toComputerByInputMetricKey);
+  private static Collection<MeasureComputerWrapper> getDependents(MeasureComputerWrapper measureComputer, ToComputerByKey toComputerByInputMetricKey) {
+    return measureComputer.getDefinition().getInputMetrics().stream()
+      .map(toComputerByInputMetricKey)
+      .collect(Collectors.toList());
   }
 
   private static class ToComputerByKey implements Function<String, MeasureComputerWrapper> {
@@ -155,25 +159,6 @@ public class LoadMeasureComputersStep implements ComputationStep {
     }
   }
 
-  private enum MetricToKey implements Function<Metric, String> {
-    INSTANCE;
-
-    @Nullable
-    @Override
-    public String apply(@Nonnull Metric input) {
-      return input.key();
-    }
-  }
-
-  private enum MetricsToMetricList implements Function<Metrics, List<Metric>> {
-    INSTANCE;
-
-    @Override
-    public List<Metric> apply(@Nonnull Metrics input) {
-      return input.getMetrics();
-    }
-  }
-
   private enum ToMeasureWrapper implements Function<MeasureComputer, MeasureComputerWrapper> {
     INSTANCE;
 
@@ -206,13 +191,9 @@ public class LoadMeasureComputersStep implements ComputationStep {
     }
   }
 
-  private class ValidateInputMetric implements Predicate<String> {
-    @Override
-    public boolean apply(@Nonnull String metric) {
-      checkState(pluginMetricKeys.contains(metric) || CORE_METRIC_KEYS.contains(metric),
-        "Metric '%s' cannot be used as an input metric as it's not a core metric and no plugin declare this metric", metric);
-      return true;
-    }
+  private void validateInputMetric(String metric) {
+    checkState(pluginMetricKeys.contains(metric) || CORE_METRIC_KEYS.contains(metric),
+      "Metric '%s' cannot be used as an input metric as it's not a core metric and no plugin declare this metric", metric);
   }
 
   private enum ToOutputMetrics implements Function<MeasureComputerWrapper, Collection<String>> {
@@ -224,20 +205,15 @@ public class LoadMeasureComputersStep implements ComputationStep {
     }
   }
 
-  private class ValidateOutputMetric implements Predicate<String> {
-    @Override
-    public boolean apply(@Nonnull String metric) {
-      checkState(!CORE_METRIC_KEYS.contains(metric), "Metric '%s' cannot be used as an output metric because it's a core metric", metric);
-      checkState(pluginMetricKeys.contains(metric), "Metric '%s' cannot be used as an output metric because no plugins declare this metric", metric);
-      return true;
-    }
+  private void validateOutputMetric(String metric) {
+    checkState(!CORE_METRIC_KEYS.contains(metric), "Metric '%s' cannot be used as an output metric because it's a core metric", metric);
+    checkState(pluginMetricKeys.contains(metric), "Metric '%s' cannot be used as an output metric because no plugins declare this metric", metric);
   }
 
-  private static class ValidateUniqueOutputMetric implements Predicate<MeasureComputerWrapper> {
-    private Set<String> allOutputMetrics = new HashSet<>();
+  private static class ValidateUniqueOutputMetric {
+    private final Set<String> allOutputMetrics = new HashSet<>();
 
-    @Override
-    public boolean apply(@Nonnull MeasureComputerWrapper wrapper) {
+    public boolean validate(@Nonnull MeasureComputerWrapper wrapper) {
       for (String outputMetric : wrapper.getDefinition().getOutputMetrics()) {
         checkState(!allOutputMetrics.contains(outputMetric),
           "Output metric '%s' is already defined by another measure computer '%s'", outputMetric, wrapper.getComputer());
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/QualityGateMeasuresStep.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/QualityGateMeasuresStep.java
index b267bd3a1be..4e6ff7ff6db 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/QualityGateMeasuresStep.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/QualityGateMeasuresStep.java
@@ -19,7 +19,6 @@
  */
 package org.sonar.ce.task.projectanalysis.step;
 
-import com.google.common.base.Function;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Multimap;
 import java.util.ArrayList;
@@ -28,7 +27,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
-import javax.annotation.Nonnull;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 import org.apache.commons.lang.StringUtils;
 import org.sonar.api.measures.CoreMetrics;
@@ -55,7 +55,6 @@ import org.sonar.ce.task.projectanalysis.qualitygate.QualityGateHolder;
 import org.sonar.ce.task.step.ComputationStep;
 import org.sonar.core.util.stream.MoreCollectors;
 
-import static com.google.common.collect.FluentIterable.from;
 import static java.lang.String.format;
 import static org.sonar.ce.task.projectanalysis.component.ComponentVisitor.Order.PRE_ORDER;
 import static org.sonar.ce.task.projectanalysis.qualitygate.ConditionStatus.NO_VALUE_STATUS;
@@ -146,9 +145,9 @@ public class QualityGateMeasuresStep implements ComputationStep {
     }
   }
 
-  private static Map<Condition, ConditionStatus> createStatusPerCondition(Iterable<Condition> conditions, Iterable<EvaluatedCondition> evaluatedConditions) {
-    Map<Condition, EvaluatedCondition> evaluatedConditionPerCondition = from(evaluatedConditions)
-      .uniqueIndex(EvaluatedConditionToCondition.INSTANCE);
+  private static Map<Condition, ConditionStatus> createStatusPerCondition(Collection<Condition> conditions, Collection<EvaluatedCondition> evaluatedConditions) {
+    Map<Condition, EvaluatedCondition> evaluatedConditionPerCondition = evaluatedConditions.stream()
+      .collect(Collectors.toMap(EvaluatedCondition::getCondition, Function.identity()));
 
     ImmutableMap.Builder<Condition, ConditionStatus> builder = ImmutableMap.builder();
     for (Condition condition : conditions) {
@@ -164,7 +163,7 @@ public class QualityGateMeasuresStep implements ComputationStep {
   }
 
   private void updateMeasures(Component project, Set<Condition> conditions, QualityGateDetailsDataBuilder builder) {
-    Multimap<Metric, Condition> conditionsPerMetric = conditions.stream().collect(MoreCollectors.index(Condition::getMetric, java.util.function.Function.identity()));
+    Multimap<Metric, Condition> conditionsPerMetric = conditions.stream().collect(MoreCollectors.index(Condition::getMetric, Function.identity()));
     boolean ignoredConditions = false;
     for (Map.Entry<Metric, Collection<Condition>> entry : conditionsPerMetric.asMap().entrySet()) {
       Metric metric = entry.getKey();
@@ -267,16 +266,6 @@ public class QualityGateMeasuresStep implements ComputationStep {
     }
   }
 
-  private enum EvaluatedConditionToCondition implements Function<EvaluatedCondition, Condition> {
-    INSTANCE;
-
-    @Override
-    @Nonnull
-    public Condition apply(@Nonnull EvaluatedCondition input) {
-      return input.getCondition();
-    }
-  }
-
   static class MetricEvaluationResult {
     final EvaluationResult evaluationResult;
     final Condition condition;
diff --git a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImplTest.java b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImplTest.java
index 7ce335e7871..c2ef478218a 100644
--- a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImplTest.java
+++ b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/language/LanguageRepositoryImplTest.java
@@ -35,7 +35,7 @@ public class LanguageRepositoryImplTest {
   @Test
   public void constructor_fails_is_language_have_the_same_key() {
     assertThatThrownBy(() -> new LanguageRepositoryImpl(createLanguage(SOME_LANGUAGE_KEY, " 1"), createLanguage(SOME_LANGUAGE_KEY, " 2")))
-      .isInstanceOf(IllegalArgumentException.class);
+      .isInstanceOf(IllegalStateException.class);
   }
 
   @Test
diff --git a/server/sonar-db-migration/src/test/java/org/sonar/server/platform/db/migration/engine/MigrationContainerImplTest.java b/server/sonar-db-migration/src/test/java/org/sonar/server/platform/db/migration/engine/MigrationContainerImplTest.java
index f0534766f3c..dbc1d2b1c0b 100644
--- a/server/sonar-db-migration/src/test/java/org/sonar/server/platform/db/migration/engine/MigrationContainerImplTest.java
+++ b/server/sonar-db-migration/src/test/java/org/sonar/server/platform/db/migration/engine/MigrationContainerImplTest.java
@@ -64,6 +64,19 @@ public class MigrationContainerImplTest {
   }
 
   @Test
+  public void add_duplicate_steps_has_no_effect() {
+    InternalMigrationStepRegistry registry = new MigrationStepRegistryImpl();
+    registry.add(1, "test", NoOpMigrationStep.class);
+    registry.add(2, "test2", NoOpMigrationStep.class);
+
+    SpringComponentContainer parent = new SpringComponentContainer();
+    parent.add(registry.build());
+    parent.startComponents();
+    MigrationContainerImpl underTest = new MigrationContainerImpl(parent, NoOpExecutor.class);
+    assertThat(underTest.getComponentsByType(MigrationStep.class)).hasSize(1);
+  }
+
+  @Test
   public void migration_container_lazily_instance_components() {
     assertThat(StartCallCounter.startCalls).isZero();
 
diff --git a/server/sonar-webserver-core/src/main/java/org/sonar/server/project/package-info.java b/server/sonar-webserver-core/src/main/java/org/sonar/server/project/package-info.java
new file mode 100644
index 00000000000..167d4219225
--- /dev/null
+++ b/server/sonar-webserver-core/src/main/java/org/sonar/server/project/package-info.java
@@ -0,0 +1,24 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2022 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program 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.
+ *
+ * This program 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.
+ */
+@ParametersAreNonnullByDefault
+package org.sonar.server.project;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+
diff --git a/server/sonar-webserver-webapi/src/main/java/org/sonar/server/rule/ws/RuleMapper.java b/server/sonar-webserver-webapi/src/main/java/org/sonar/server/rule/ws/RuleMapper.java
index 480be2df5d5..867e323cabd 100644
--- a/server/sonar-webserver-webapi/src/main/java/org/sonar/server/rule/ws/RuleMapper.java
+++ b/server/sonar-webserver-webapi/src/main/java/org/sonar/server/rule/ws/RuleMapper.java
@@ -19,15 +19,14 @@
  */
 package org.sonar.server.rule.ws;
 
-import com.google.common.base.Function;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 import javax.annotation.CheckForNull;
-import javax.annotation.Nonnull;
 import org.sonar.api.resources.Language;
 import org.sonar.api.resources.Languages;
 import org.sonar.api.rule.RuleKey;
@@ -437,7 +436,7 @@ public class RuleMapper {
     INSTANCE;
 
     @Override
-    public Rules.Rule.Param apply(@Nonnull RuleParamDto param) {
+    public Rules.Rule.Param apply(RuleParamDto param) {
       Rules.Rule.Param.Builder paramResponse = Rules.Rule.Param.newBuilder();
       paramResponse.setKey(param.getName());
       if (param.getDescription() != null) {
diff --git a/server/sonar-webserver/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel.java b/server/sonar-webserver/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel.java
index 9d8bc2b26c2..74eafc913bf 100644
--- a/server/sonar-webserver/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel.java
+++ b/server/sonar-webserver/src/main/java/org/sonar/server/platform/platformlevel/PlatformLevel.java
@@ -26,7 +26,6 @@ import org.sonar.core.platform.SpringComponentContainer;
 import org.sonar.server.platform.WebServer;
 
 import static com.google.common.base.Preconditions.checkNotNull;
-import static java.util.Objects.requireNonNull;
 
 public abstract class PlatformLevel {
   private final String name;
diff --git a/sonar-core/src/main/java/org/sonar/core/extension/CoreExtensionsInstaller.java b/sonar-core/src/main/java/org/sonar/core/extension/CoreExtensionsInstaller.java
index cc436fbc0d4..cba56638cbd 100644
--- a/sonar-core/src/main/java/org/sonar/core/extension/CoreExtensionsInstaller.java
+++ b/sonar-core/src/main/java/org/sonar/core/extension/CoreExtensionsInstaller.java
@@ -84,10 +84,6 @@ public abstract class CoreExtensionsInstaller {
     coreExtension.load(context);
   }
 
-  private <T> boolean hasSupportedAnnotation(T component) {
-    return AnnotationUtils.getAnnotation(component, supportedAnnotationType) != null;
-  }
-
   private class ContextImpl implements CoreExtension.Context {
     private final ExtensionContainer container;
     private final Predicate<Object> extensionFilter;
@@ -147,5 +143,9 @@ public abstract class CoreExtensionsInstaller {
       }
       return false;
     }
+
+    private <T> boolean hasSupportedAnnotation(T component) {
+      return AnnotationUtils.getAnnotation(component, supportedAnnotationType) != null;
+    }
   }
 }
diff --git a/sonar-scanner-engine/src/main/java/org/sonar/scanner/repository/ReferenceBranchSupplier.java b/sonar-scanner-engine/src/main/java/org/sonar/scanner/repository/ReferenceBranchSupplier.java
index b700fa59ada..a389741ff36 100644
--- a/sonar-scanner-engine/src/main/java/org/sonar/scanner/repository/ReferenceBranchSupplier.java
+++ b/sonar-scanner-engine/src/main/java/org/sonar/scanner/repository/ReferenceBranchSupplier.java
@@ -90,7 +90,7 @@ public class ReferenceBranchSupplier {
     Optional<String> value = configuration.get(NEW_CODE_PARAM_KEY);
     if (value.isPresent()) {
       String referenceBranchName = value.get();
-      if (getBranchName().equals(referenceBranchName)) {
+      if (referenceBranchName.equals(getBranchName())) {
         throw new IllegalStateException(format("Reference branch set with '%s' points to the current branch '%s'", NEW_CODE_PARAM_KEY, referenceBranchName));
       }
       return referenceBranchName;
diff --git a/sonar-scanner-protocol/src/test/java/org/sonar/scanner/protocol/output/ScannerReportReaderTest.java b/sonar-scanner-protocol/src/test/java/org/sonar/scanner/protocol/output/ScannerReportReaderTest.java
index 269bacef2d4..e7588076b57 100644
--- a/sonar-scanner-protocol/src/test/java/org/sonar/scanner/protocol/output/ScannerReportReaderTest.java
+++ b/sonar-scanner-protocol/src/test/java/org/sonar/scanner/protocol/output/ScannerReportReaderTest.java
@@ -226,6 +226,12 @@ public class ScannerReportReaderTest {
   }
 
   @Test
+  public void read_analysis_cache_returns_null_if_no_file_exists() {
+    ScannerReportReader reader = new ScannerReportReader(dir);
+    assertThat(reader.getAnalysisCache()).isNull();
+  }
+
+    @Test
   public void empty_list_if_no_duplication_block_found() {
     assertThat(underTest.readComponentDuplications(UNKNOWN_COMPONENT_REF)).toIterable().isEmpty();
   }