bug 293926: CompareUIPlugin.findContentViewerDescriptor returns null even if a viewer is registered via extension point="org.eclipse.compare.contentMergeViewers"

2 files changed, 115 insertions, 1 deletions

diff --git a/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/AllTests.java b/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/AllTests.java
index 27de4c9a8..a47c61fc2 100644
--- a/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/AllTests.java
+++ b/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/AllTests.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2010 IBM Corporation and others.
+ * Copyright (c) 2000, 2011 IBM Corporation and others.
  * 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
@@ -35,6 +35,7 @@ public class AllTests {
 		suite.addTestSuite(PatchLinesTest.class);
 		suite.addTestSuite(PatchUITest.class);
 		suite.addTestSuite(RangeDifferencerThreeWayDiffTest.class);
+		suite.addTestSuite(CompareUIPluginTest.class);
 		// $JUnit-END$
 		return suite;
 	}
diff --git a/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/CompareUIPluginTest.java b/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/CompareUIPluginTest.java
new file mode 100644
index 000000000..3107b5f74
--- /dev/null
+++ b/tests/org.eclipse.compare.tests/src/org/eclipse/compare/tests/CompareUIPluginTest.java
@@ -0,0 +1,113 @@
+/*******************************************************************************
+ * Copyright (c) 2011 IBM Corporation and others.
+ * 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:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.compare.tests;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+
+import junit.framework.TestCase;
+
+import org.eclipse.compare.CompareConfiguration;
+import org.eclipse.compare.IStreamContentAccessor;
+import org.eclipse.compare.ITypedElement;
+import org.eclipse.compare.internal.CompareUIPlugin;
+import org.eclipse.compare.internal.ViewerDescriptor;
+import org.eclipse.compare.structuremergeviewer.DiffNode;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.swt.graphics.Image;
+
+public class CompareUIPluginTest extends TestCase {
+
+	private static class UnknownTypedElement implements ITypedElement {
+		public Image getImage() {
+			return null;
+		}
+
+		public String getName() {
+			return "test";
+		}
+
+		public String getType() {
+			return UNKNOWN_TYPE;
+		}
+	}
+
+	private static class TextTypedElement implements ITypedElement {
+		public Image getImage() {
+			return null;
+		}
+
+		public String getName() {
+			return "test";
+		}
+
+		public String getType() {
+			return TEXT_TYPE;
+		}
+	}
+
+	private static class TextTypedElementStreamAccessor implements ITypedElement, IStreamContentAccessor {
+		public Image getImage() {
+			return null;
+		}
+
+		public String getName() {
+			return "test";
+		}
+
+		public String getType() {
+			return TEXT_TYPE;
+		}
+
+		public InputStream getContents() throws CoreException {
+			/*
+			 * Whatever we return has no importance as long as it is not "null", this is only to make
+			 * CompareUIPlugin#guessType happy. However, it is only happy if what we return resembles a text.
+			 */
+			return new ByteArrayInputStream(new byte[] {' '});
+		}
+	}
+
+	public void testFindContentViewerDescriptor_UnknownType() {
+		CompareConfiguration cc = new CompareConfiguration();
+		DiffNode in = new DiffNode(new UnknownTypedElement(), new UnknownTypedElement());
+		ViewerDescriptor[] result = CompareUIPlugin.getDefault().findContentViewerDescriptor(null, in, cc);
+
+		// API Compatibility : "no descriptor found" should return a null array instead of a 0-lengthed one.
+		assertNull(result);
+	}
+
+	public void testFindContentViewerDescriptor_TextType_NotStreamAccessor() {
+		CompareConfiguration cc = new CompareConfiguration();
+		DiffNode in = new DiffNode(new TextTypedElement(), new TextTypedElement());
+		ViewerDescriptor[] result = CompareUIPlugin.getDefault().findContentViewerDescriptor(null, in, cc);
+
+		/*
+		 * "TextTypedElement" is "text" typed : it thus has a Content Viewer attached. However, this content
+		 * viewer is currently NOT returned because of bug 293926
+		 */
+		assertNotNull(result);
+		assertEquals(1, result.length);
+	}
+
+	public void testFindContentViewerDescriptorForTextType_StreamAccessor() {
+		CompareConfiguration cc = new CompareConfiguration();
+		DiffNode in = new DiffNode(new TextTypedElementStreamAccessor(), new TextTypedElementStreamAccessor());
+		ViewerDescriptor[] result = CompareUIPlugin.getDefault().findContentViewerDescriptor(null, in, cc);
+
+		/*
+		 * "TextTypedElement" is "text" typed : it thus has a Content Viewer attached. However, the content
+		 * viewer will only be returned because we made our "ITypedElement" be an IStreamContentAccessor.
+		 */
+		assertNotNull(result);
+		assertEquals(1, result.length);
+	}
+}
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