Add assertThrows to ScoutAssert

Change-Id: Icaf2369fd366ad134652ceedc01f71885b36e536
Reviewed-on: https://git.eclipse.org/r/115951
Tested-by: Hudson CI
Reviewed-by: Andi Bur <andi.bur@gmail.com>

3 files changed, 88 insertions, 2 deletions

diff --git a/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ITestExecutable.java b/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ITestExecutable.java
new file mode 100644
index 0000000000..1c349527be
--- /dev/null
+++ b/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ITestExecutable.java
@@ -0,0 +1,20 @@
+/*******************************************************************************
+ * Copyright (c) 2018 BSI Business Systems Integration AG.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     BSI Business Systems Integration AG - initial API and implementation
+ ******************************************************************************/
+package org.eclipse.scout.rt.testing.platform.util;
+
+/**
+ * Functional interface allowing lambda expressions that are throwing any {@link Throwable}.
+ */
+@FunctionalInterface
+public interface ITestExecutable {
+
+  void execute() throws Throwable; // NOSONAR squid:S1181
+}
diff --git a/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssert.java b/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssert.java
index 1ab85c10ad..5d1b0b69c0 100644
--- a/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssert.java
+++ b/org.eclipse.scout.rt.platform.test/src/main/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssert.java
@@ -135,4 +135,25 @@ public final class ScoutAssert {
     List<String> actualLines = IOUtility.readLines(actualFile, charsetName);
     assertListEquals(expectedLines, actualLines);
   }
+
+  /**
+   * Asserts that the given {@link ITestExecutable} throws an exception of expected type. <br/>
+   * This method was motivated by Junit 5 and could be replaced when upgrading form Junit 4.
+   */
+  public static <T extends Throwable> T assertThrows(Class<T> expectedType, ITestExecutable r) {
+    try {
+      r.execute();
+    }
+    catch (AssertionError e) {
+      throw e;
+    }
+    catch (Throwable t) { // NOSONAR squid:S1181
+      if (expectedType.isInstance(t)) {
+        return expectedType.cast(t);
+      }
+      throw new AssertionError("Expecting [" + expectedType.getName() + "] but a [" + t.getClass().getName() + "] was thrown", t);
+    }
+
+    throw new AssertionError("Expecting [" + expectedType.getName() + "] but nothing was thrown");
+  }
 }
diff --git a/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssertTest.java b/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssertTest.java
index 9594a9948a..da24cb08f4 100644
--- a/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssertTest.java
+++ b/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/testing/platform/util/ScoutAssertTest.java
@@ -18,11 +18,13 @@ import static org.junit.Assert.fail;
 
 import java.math.BigDecimal;
 
+import org.eclipse.scout.rt.platform.exception.PlatformError;
+import org.eclipse.scout.rt.platform.exception.VetoException;
 import org.junit.Test;
 
 /**
  * Tests for {@link ScoutAssert}.
- * 
+ *
  * @since 3.10.0-M3
  */
 public class ScoutAssertTest {
@@ -30,7 +32,7 @@ public class ScoutAssertTest {
   /**
    * Test for {@link ScoutAssert#assertComparableEquals(Comparable, Comparable)} and
    * {@link ScoutAssert#assertComparableEquals(String, Comparable, Comparable)}.
-   * 
+   *
    * @See Bug 420183
    */
   @Test
@@ -96,4 +98,47 @@ public class ScoutAssertTest {
     }
   }
 
+  @Test
+  public void testAssertThrows() {
+    // runtime exception
+    final VetoException runtimeException = new VetoException("msg");
+    assertSame(runtimeException, ScoutAssert.assertThrows(VetoException.class, () -> raise(runtimeException)));
+    assertSame(runtimeException, ScoutAssert.assertThrows(RuntimeException.class, () -> raise(runtimeException)));
+    assertSame(runtimeException, ScoutAssert.assertThrows(Exception.class, () -> raise(runtimeException)));
+    assertSame(runtimeException, ScoutAssert.assertThrows(Throwable.class, () -> raise(runtimeException)));
+    try {
+      ScoutAssert.assertThrows(Error.class, () -> raise(runtimeException));
+      fail("expecting assertion to fail");
+    }
+    catch (AssertionError expected) {
+    }
+
+    // runtime exception
+    final InterruptedException exception = new InterruptedException("msg");
+    assertSame(exception, ScoutAssert.assertThrows(InterruptedException.class, () -> raise(exception)));
+    assertSame(exception, ScoutAssert.assertThrows(Exception.class, () -> raise(exception)));
+    assertSame(exception, ScoutAssert.assertThrows(Throwable.class, () -> raise(exception)));
+    try {
+      ScoutAssert.assertThrows(Error.class, () -> raise(exception));
+      fail("expecting assertion to fail");
+    }
+    catch (AssertionError expected) {
+    }
+
+    // error
+    final PlatformError error = new PlatformError("msg");
+    assertSame(error, ScoutAssert.assertThrows(PlatformError.class, () -> raise(error)));
+    assertSame(error, ScoutAssert.assertThrows(Error.class, () -> raise(error)));
+    assertSame(error, ScoutAssert.assertThrows(Throwable.class, () -> raise(error)));
+    try {
+      ScoutAssert.assertThrows(Exception.class, () -> raise(error));
+      fail("expecting assertion to fail");
+    }
+    catch (AssertionError expected) {
+    }
+  }
+
+  private void raise(Throwable t) throws Throwable {
+    throw t;
+  }
 }