Automatic merge from branch-4.5

* origin/branch-4.5:
  SONAR-4898 add missing tests
  SONAR-4898 add missing tests
  Use correct temp dir for Ruby on Rails app
  Fail server startup if can not connect to DB

16 files changed, 243 insertions, 92 deletions

diff --git a/server/sonar-process/pom.xml b/server/sonar-process/pom.xml
index 25916e9ae41..387e5ecc519 100644
--- a/server/sonar-process/pom.xml
+++ b/server/sonar-process/pom.xml
@@ -41,13 +41,8 @@
     </dependency>
 
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>org.easytesting</groupId>
-      <artifactId>fest-assert</artifactId>
+      <groupId>org.codehaus.sonar</groupId>
+      <artifactId>sonar-testing-harness</artifactId>
       <scope>test</scope>
     </dependency>
     <dependency>
@@ -56,11 +51,6 @@
       <scope>test</scope>
     </dependency>
     <dependency>
-      <groupId>org.hamcrest</groupId>
-      <artifactId>hamcrest-all</artifactId>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava</artifactId>
       <scope>test</scope>
diff --git a/server/sonar-process/src/main/java/org/sonar/process/ProcessCommands.java b/server/sonar-process/src/main/java/org/sonar/process/ProcessCommands.java
index d79f0f92899..1c7af0c004e 100644
--- a/server/sonar-process/src/main/java/org/sonar/process/ProcessCommands.java
+++ b/server/sonar-process/src/main/java/org/sonar/process/ProcessCommands.java
@@ -52,6 +52,7 @@ public class ProcessCommands {
     this.stopFile = new File(directory, processKey + ".stop");
   }
 
+  // visible for tests
   ProcessCommands(File readyFile, File stopFile) {
     this.readyFile = readyFile;
     this.stopFile = stopFile;
diff --git a/server/sonar-process/src/main/java/org/sonar/process/StopWatcher.java b/server/sonar-process/src/main/java/org/sonar/process/StopWatcher.java
index 2441a193748..4ba726a2d85 100644
--- a/server/sonar-process/src/main/java/org/sonar/process/StopWatcher.java
+++ b/server/sonar-process/src/main/java/org/sonar/process/StopWatcher.java
@@ -21,16 +21,26 @@ package org.sonar.process;
 
 import org.slf4j.LoggerFactory;
 
+/**
+ * This watchdog asks for graceful termination of process when the file
+ * &lt;process_key&gt;.stop is created in temp directory.
+ */
 public class StopWatcher extends Thread {
 
   private final Stoppable stoppable;
   private final ProcessCommands commands;
   private boolean watching = true;
+  private final long delayMs;
 
   public StopWatcher(ProcessCommands commands, Stoppable stoppable) {
+    this(commands, stoppable, 500L);
+  }
+
+  StopWatcher(ProcessCommands commands, Stoppable stoppable, long delayMs) {
     super("Stop Watcher");
     this.commands = commands;
     this.stoppable = stoppable;
+    this.delayMs = delayMs;
   }
 
   @Override
@@ -44,7 +54,7 @@ public class StopWatcher extends Thread {
           watching = false;
         } else {
           try {
-            Thread.sleep(500L);
+            Thread.sleep(delayMs);
           } catch (InterruptedException ignored) {
             watching = false;
           }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/ConfigurationUtilsTest.java b/server/sonar-process/src/test/java/org/sonar/process/ConfigurationUtilsTest.java
index de928b93850..4aa072a6eb3 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/ConfigurationUtilsTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/ConfigurationUtilsTest.java
@@ -24,6 +24,7 @@ import org.apache.commons.io.FileUtils;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
+import org.sonar.test.TestUtils;
 
 import java.io.File;
 import java.util.Map;
@@ -92,4 +93,9 @@ public class ConfigurationUtilsTest {
       assertThat(e).hasMessage("Could not read properties from file: " + propsFile.getAbsolutePath());
     }
   }
+
+  @Test
+  public void private_constructor() throws Exception {
+    TestUtils.assertPrivateConstructor(ConfigurationUtils.class);
+  }
 }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/LoopbackAddressTest.java b/server/sonar-process/src/test/java/org/sonar/process/LoopbackAddressTest.java
index 6a8819c3a81..b612e24342d 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/LoopbackAddressTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/LoopbackAddressTest.java
@@ -21,6 +21,7 @@ package org.sonar.process;
 
 import com.google.common.collect.Iterators;
 import org.junit.Test;
+import org.sonar.test.TestUtils;
 
 import java.net.NetworkInterface;
 import java.util.Collections;
@@ -48,4 +49,9 @@ public class LoopbackAddressTest {
       assertThat(e).hasMessage("Impossible to get a IPv4 loopback address");
     }
   }
+
+  @Test
+  public void private_constructor() throws Exception {
+    TestUtils.assertPrivateConstructor(LoopbackAddress.class);
+  }
 }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/NetworkUtilsTest.java b/server/sonar-process/src/test/java/org/sonar/process/NetworkUtilsTest.java
index 9eb41dbf6ac..0462f76707a 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/NetworkUtilsTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/NetworkUtilsTest.java
@@ -20,8 +20,7 @@
 package org.sonar.process;
 
 import org.junit.Test;
-
-import java.net.ServerSocket;
+import org.sonar.test.TestUtils;
 
 import static org.fest.assertions.Assertions.assertThat;
 
@@ -38,23 +37,11 @@ public class NetworkUtilsTest {
     int port1 = NetworkUtils.freePort();
     int port2 = NetworkUtils.freePort();
 
-    assertThat(port1).isGreaterThan(1024);
-    assertThat(port2).isGreaterThan(1024);
-
     assertThat(port1).isNotSameAs(port2);
   }
 
   @Test
-  public void find_multiple_free_non_adjacent_port() throws Exception {
-    int port1 = NetworkUtils.freePort();
-
-    ServerSocket socket = new ServerSocket(port1 + 1);
-
-    int port2 = NetworkUtils.freePort();
-
-    assertThat(port1).isGreaterThan(1024);
-    assertThat(port2).isGreaterThan(1024);
-
-    assertThat(port1).isNotSameAs(port2);
+  public void private_constructor() throws Exception {
+    TestUtils.assertPrivateConstructor(NetworkUtils.class);
   }
 }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/ProcessCommandsTest.java b/server/sonar-process/src/test/java/org/sonar/process/ProcessCommandsTest.java
index e81a537e2ee..984fbed74f7 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/ProcessCommandsTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/ProcessCommandsTest.java
@@ -37,7 +37,20 @@ public class ProcessCommandsTest {
   public TemporaryFolder temp = new TemporaryFolder();
 
   @Test
-  public void delete_files_on_monitor_startup() throws Exception {
+  public void fail_to_init_if_dir_does_not_exist() throws Exception {
+    File dir = temp.newFolder();
+    FileUtils.deleteQuietly(dir);
+
+    try {
+      new ProcessCommands(dir, "web");
+      fail();
+    } catch (IllegalArgumentException e) {
+      assertThat(e).hasMessage("Not a valid directory: " + dir.getAbsolutePath());
+    }
+  }
+
+  @Test
+  public void delete_files_on_prepare() throws Exception {
     File dir = temp.newFolder();
     assertThat(dir).exists();
     FileUtils.touch(new File(dir, "web.ready"));
@@ -67,18 +80,32 @@ public class ProcessCommandsTest {
 
   @Test
   public void child_process_create_file_when_ready() throws Exception {
-    File readyFile = temp.newFile();
+    File dir = temp.newFolder();
 
-    ProcessCommands commands = new ProcessCommands(readyFile, temp.newFile());
+    ProcessCommands commands = new ProcessCommands(dir, "web");
     commands.prepare();
     assertThat(commands.isReady()).isFalse();
-    assertThat(readyFile).doesNotExist();
+    assertThat(commands.getReadyFile()).doesNotExist();
 
     commands.setReady();
     assertThat(commands.isReady()).isTrue();
-    assertThat(readyFile).exists();
+    assertThat(commands.getReadyFile()).exists().isFile();
 
     commands.endWatch();
-    assertThat(readyFile).doesNotExist();
+    assertThat(commands.getReadyFile()).doesNotExist();
+  }
+
+  @Test
+  public void ask_for_stop() throws Exception {
+    File dir = temp.newFolder();
+
+    ProcessCommands commands = new ProcessCommands(dir, "web");
+    assertThat(commands.askedForStop()).isFalse();
+    assertThat(commands.getStopFile()).doesNotExist();
+
+    commands.askForStop();
+    assertThat(commands.askedForStop()).isTrue();
+    assertThat(commands.getStopFile()).exists().isFile();
+    assertThat(commands.getStopFile().getName()).isEqualTo("web.stop");
   }
 }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/ProcessUtilsTest.java b/server/sonar-process/src/test/java/org/sonar/process/ProcessUtilsTest.java
new file mode 100644
index 00000000000..ae1f53b2653
--- /dev/null
+++ b/server/sonar-process/src/test/java/org/sonar/process/ProcessUtilsTest.java
@@ -0,0 +1,31 @@
+/*
+ * 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.process;
+
+import org.junit.Test;
+import org.sonar.test.TestUtils;
+
+public class ProcessUtilsTest {
+
+  @Test
+  public void private_constructor() throws Exception {
+    TestUtils.assertPrivateConstructor(ProcessUtils.class);
+  }
+}
diff --git a/server/sonar-process/src/test/java/org/sonar/process/PropsTest.java b/server/sonar-process/src/test/java/org/sonar/process/PropsTest.java
index 5d283b44f8f..25feeef39b8 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/PropsTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/PropsTest.java
@@ -19,8 +19,12 @@
  */
 package org.sonar.process;
 
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
 
+import java.io.File;
+import java.io.IOException;
 import java.util.Properties;
 
 import static org.fest.assertions.Assertions.assertThat;
@@ -28,8 +32,11 @@ import static org.fest.assertions.Fail.fail;
 
 public class PropsTest {
 
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
   @Test
-  public void of() throws Exception {
+  public void value() throws Exception {
     Properties p = new Properties();
     p.setProperty("foo", "bar");
     Props props = new Props(p);
@@ -38,10 +45,18 @@ public class PropsTest {
     assertThat(props.value("foo", "default value")).isEqualTo("bar");
     assertThat(props.value("unknown")).isNull();
     assertThat(props.value("unknown", "default value")).isEqualTo("default value");
+
+    assertThat(props.nonNullValue("foo")).isEqualTo("bar");
+    try {
+      props.nonNullValue("other");
+      fail();
+    } catch (IllegalArgumentException e) {
+      assertThat(e).hasMessage("Missing property: other");
+    }
   }
 
   @Test
-  public void intOf() throws Exception {
+  public void valueAsInt() throws Exception {
     Properties p = new Properties();
     p.setProperty("foo", "33");
     p.setProperty("blank", "");
@@ -56,7 +71,7 @@ public class PropsTest {
   }
 
   @Test
-  public void intOf_not_integer() throws Exception {
+  public void valueAsInt_not_integer() throws Exception {
     Properties p = new Properties();
     p.setProperty("foo", "bar");
     Props props = new Props(p);
@@ -130,6 +145,21 @@ public class PropsTest {
     // do not decrypt
     assertThat(props.rawProperties().get("encrypted_prop")).isEqualTo("{aes}abcde");
     assertThat(props.rawProperties().get("clear_prop")).isEqualTo("foo");
+  }
 
+  @Test
+  public void nonNullValueAsFile() throws IOException {
+    File file = temp.newFile();
+    Props props = new Props(new Properties());
+    props.set("path", file.getAbsolutePath());
+
+    assertThat(props.nonNullValueAsFile("path")).isEqualTo(file);
+
+    try {
+      props.nonNullValueAsFile("other_path");
+      fail();
+    } catch (IllegalArgumentException e) {
+      assertThat(e).hasMessage("Property other_path is not set");
+    }
   }
 }
diff --git a/server/sonar-process/src/test/java/org/sonar/process/StopWatcherTest.java b/server/sonar-process/src/test/java/org/sonar/process/StopWatcherTest.java
new file mode 100644
index 00000000000..8a6545e5819
--- /dev/null
+++ b/server/sonar-process/src/test/java/org/sonar/process/StopWatcherTest.java
@@ -0,0 +1,59 @@
+/*
+ * 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.process;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import static org.mockito.Mockito.*;
+
+public class StopWatcherTest {
+
+  @Rule
+  public TemporaryFolder temp = new TemporaryFolder();
+
+  @Test(timeout = 1000L)
+  public void stop_if_receive_command() throws Exception {
+    ProcessCommands commands = mock(ProcessCommands.class);
+    when(commands.askedForStop()).thenReturn(false).thenReturn(true);
+    Stoppable stoppable = mock(Stoppable.class);
+
+    StopWatcher watcher = new StopWatcher(commands, stoppable, 10L);
+    watcher.start();
+    watcher.join();
+
+    verify(stoppable).stopAsync();
+  }
+
+  @Test(timeout = 1000L)
+  public void stop_watching_on_interruption() throws Exception {
+    ProcessCommands commands = mock(ProcessCommands.class);
+    when(commands.askedForStop()).thenReturn(false);
+    Stoppable stoppable = mock(Stoppable.class);
+
+    StopWatcher watcher = new StopWatcher(commands, stoppable, 1000L);
+    watcher.start();
+    Thread.sleep(50L);
+    watcher.interrupt();
+
+    verify(stoppable, never()).stopAsync();
+  }
+}
diff --git a/server/sonar-process/src/test/java/org/sonar/process/StopperThreadTest.java b/server/sonar-process/src/test/java/org/sonar/process/StopperThreadTest.java
index e1eed0548aa..494457134a8 100644
--- a/server/sonar-process/src/test/java/org/sonar/process/StopperThreadTest.java
+++ b/server/sonar-process/src/test/java/org/sonar/process/StopperThreadTest.java
@@ -25,55 +25,47 @@ import org.junit.rules.TemporaryFolder;
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 
-import java.io.File;
-
-import static org.fest.assertions.Assertions.assertThat;
-import static org.mockito.Mockito.doAnswer;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.*;
 
 public class StopperThreadTest {
+
   @Rule
   public TemporaryFolder temp = new TemporaryFolder();
 
-
   @Test(timeout = 3000L)
   public void stop_in_a_timely_fashion() throws Exception {
-//    File dir = temp.newFile();
-//    ProcessCommands commands = new ProcessCommands(dir, "foo");
-//    assertThat(dir).exists();
-//    Monitored monitored = mock(Monitored.class);
-//
-//    // max stop timeout is 5 seconds, but test fails after 3 seconds
-//    // -> guarantees that stop is immediate
-//    StopperThread stopper = new StopperThread(monitored, commands, 5000L);
-//    stopper.start();
-//    stopper.join();
-//
-//    verify(monitored).stop();
-//    assertThat(dir).doesNotExist();
+    ProcessCommands commands = mock(ProcessCommands.class);
+    Monitored monitored = mock(Monitored.class);
+
+    // max stop timeout is 5 seconds, but test fails after 3 seconds
+    // -> guarantees that stop is immediate
+    StopperThread stopper = new StopperThread(monitored, commands, 5000L);
+    stopper.start();
+    stopper.join();
+
+    verify(monitored).stop();
+    verify(commands).endWatch();
   }
 
   @Test(timeout = 3000L)
   public void stop_timeout() throws Exception {
-//    File file = temp.newFile();
-//    ProcessCommands commands = new ProcessCommands(file);
-//    assertThat(file).exists();
-//    Monitored monitored = mock(Monitored.class);
-//    doAnswer(new Answer() {
-//      @Override
-//      public Object answer(InvocationOnMock invocationOnMock) throws Throwable {
-//        Thread.sleep(10000L);
-//        return null;
-//      }
-//    }).when(monitored).stop();
-//
-//    // max stop timeout is 10 milliseconds
-//    StopperThread stopper = new StopperThread(monitored, commands, 10L);
-//    stopper.start();
-//    stopper.join();
-//
-//    verify(monitored).stop();
-//    assertThat(file).doesNotExist();
+    ProcessCommands commands = mock(ProcessCommands.class);
+    Monitored monitored = mock(Monitored.class);
+    doAnswer(new Answer() {
+      @Override
+      public Object answer(InvocationOnMock invocationOnMock) throws Throwable {
+        Thread.sleep(10000L);
+        return null;
+      }
+    }).when(monitored).stop();
+
+    // max stop timeout is 50 milliseconds
+    StopperThread stopper = new StopperThread(monitored, commands, 50L);
+    stopper.start();
+    stopper.join();
+
+    verify(monitored).stop();
+    // even if stopper was interrupted, stop watching process
+    verify(commands).endWatch();
   }
 }
diff --git a/server/sonar-web/src/main/webapp/WEB-INF/config/environment.rb b/server/sonar-web/src/main/webapp/WEB-INF/config/environment.rb
index 986137d1976..81f897e66a3 100644
--- a/server/sonar-web/src/main/webapp/WEB-INF/config/environment.rb
+++ b/server/sonar-web/src/main/webapp/WEB-INF/config/environment.rb
@@ -72,7 +72,7 @@ Rails::Initializer.run do |config|
   # The development mode (real-time edition of ruby code) can be enabled on an app by replacing the
   # following line by :
   # config.plugin_paths << '/absolute/path/to/myproject/src/main/resources/org/sonar/ror'
-  config.plugin_paths << "#{Java::OrgSonarServerUi::JRubyFacade.getInstance().getServerHome()}/temp/ror"
+  config.plugin_paths << "#{Java::JavaLang::System.getProperty("java.io.tmpdir")}/ror"
 
   # Force all environments to use the same logger level
   # (by default production uses :info, the others :debug)
diff --git a/sonar-application/pom.xml b/sonar-application/pom.xml
index 547bff09e2d..b054c0bd128 100644
--- a/sonar-application/pom.xml
+++ b/sonar-application/pom.xml
@@ -154,18 +154,8 @@
 
     <!-- unit tests -->
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>org.hamcrest</groupId>
-      <artifactId>hamcrest-all</artifactId>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>org.easytesting</groupId>
-      <artifactId>fest-assert</artifactId>
+      <groupId>org.codehaus.sonar</groupId>
+      <artifactId>sonar-testing-harness</artifactId>
       <scope>test</scope>
     </dependency>
     <dependency>
diff --git a/sonar-application/src/test/java/org/sonar/application/DefaultSettingsTest.java b/sonar-application/src/test/java/org/sonar/application/DefaultSettingsTest.java
index 11bcb2f5631..49a66bc590c 100644
--- a/sonar-application/src/test/java/org/sonar/application/DefaultSettingsTest.java
+++ b/sonar-application/src/test/java/org/sonar/application/DefaultSettingsTest.java
@@ -21,6 +21,7 @@ package org.sonar.application;
 
 import org.junit.Test;
 import org.sonar.process.Props;
+import org.sonar.test.TestUtils;
 
 import java.util.Properties;
 
@@ -56,4 +57,9 @@ public class DefaultSettingsTest {
     DefaultSettings.init(props);
     assertThat(props.valueAsInt("sonar.search.port")).isGreaterThan(0);
   }
+
+  @Test
+  public void private_constructor() throws Exception {
+    TestUtils.assertPrivateConstructor(DefaultSettings.class);
+  }
 }
diff --git a/sonar-core/src/main/java/org/sonar/core/persistence/DefaultDatabase.java b/sonar-core/src/main/java/org/sonar/core/persistence/DefaultDatabase.java
index d8a0dadc24b..50e7a54790a 100644
--- a/sonar-core/src/main/java/org/sonar/core/persistence/DefaultDatabase.java
+++ b/sonar-core/src/main/java/org/sonar/core/persistence/DefaultDatabase.java
@@ -111,8 +111,8 @@ public class DefaultDatabase implements Database {
     try {
       LOG.debug("Testing JDBC connection");
       connection = datasource.getConnection();
-    } catch (Exception e) {
-      LOG.error("Can not connect to database. Please check connectivity and settings (see the properties prefixed by 'sonar.jdbc.').", e);
+    } catch (SQLException e) {
+      throw new IllegalStateException("Can not connect to database. Please check connectivity and settings (see the properties prefixed by 'sonar.jdbc.').", e);
     } finally {
       DbUtils.closeQuietly(connection);
     }
diff --git a/sonar-testing-harness/src/main/java/org/sonar/test/TestUtils.java b/sonar-testing-harness/src/main/java/org/sonar/test/TestUtils.java
index e537466d262..0a5d8fcaef0 100644
--- a/sonar-testing-harness/src/main/java/org/sonar/test/TestUtils.java
+++ b/sonar-testing-harness/src/main/java/org/sonar/test/TestUtils.java
@@ -23,8 +23,13 @@ import org.apache.commons.io.FileUtils;
 import org.apache.commons.lang.StringUtils;
 
 import java.io.File;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Modifier;
 import java.net.URL;
 
+import static org.fest.assertions.Assertions.assertThat;
+import static org.fest.assertions.Fail.fail;
+
 /**
  * Utilities for unit tests
  *
@@ -67,4 +72,15 @@ public final class TestUtils {
     resourcePath += path;
     return getResource(resourcePath);
   }
+
+  public static void assertPrivateConstructor(Class clazz) {
+    try {
+      Constructor constructor = clazz.getDeclaredConstructor();
+      assertThat(Modifier.isPrivate(constructor.getModifiers())).isTrue();
+      constructor.setAccessible(true);
+      constructor.newInstance();
+    } catch (Exception e) {
+      fail("Fail to instantiate " + clazz, e);
+    }
+  }
 }