Simplify and correct FileSystemTests eclipse-platform#783

Several test classes extend the FileSystemTest. This class only provides
some utility functions and always creates a local and an in-memory file
store, even if the actual test does not need it.

This change simplifies the test classes by removing the FileSystemTest
super class. The necessary utilities are moved to a utility class. The
file store creation logic is moved to an according JUnit test rule that
can be instantiated for a local or in-memory file store and keeps track
of setup and teardown.
This also fixes a bug in interwoven, inherited setup and teardown
functions (eclipse-platform#783)

Fixes eclipse-platform#783.

resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/filesystem/CreateDirectoryTest.java

@@ -13,6 +13,9 @@
  *******************************************************************************/
 package org.eclipse.core.tests.filesystem;
 
+import static org.eclipse.core.tests.filesystem.FileSystemTestUtil.ensureDoesNotExist;
+import static org.eclipse.core.tests.filesystem.FileSystemTestUtil.ensureExists;
+import static org.eclipse.core.tests.filesystem.FileSystemTestUtil.getMonitor;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThrows;
@@ -27,20 +30,28 @@
 import org.eclipse.core.filesystem.IFileStore;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.tests.filesystem.FileStoreCreationRule.FileSystemType;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 
 /**
  * Black box testing of mkdir method.
  */
-public class CreateDirectoryTest extends FileSystemTest {
+public class CreateDirectoryTest {
 	protected IFileStore topDir, subDir, file, subFile;
 
+	@Rule
+	public final FileStoreCreationRule localFileStoreRule = new FileStoreCreationRule(FileSystemType.LOCAL);
+
+	@Rule
+	public final FileStoreCreationRule inMemoryFileStoreRule = new FileStoreCreationRule(FileSystemType.IN_MEMORY);
+
 	@Before
-	@Override
 	public void setUp() throws Exception {
-		super.setUp();
+		IFileStore baseStore = inMemoryFileStoreRule.getFileStore();
+		baseStore.mkdir(EFS.NONE, null);
 		topDir = baseStore.getChild("topDir");
 		subDir = topDir.getChild("subDir");
 		file = baseStore.getChild("file");
@@ -51,9 +62,7 @@ public void setUp() throws Exception {
 	}
 
 	@After
-	@Override
 	public void tearDown() throws Exception {
-		super.tearDown();
 		ensureDoesNotExist(topDir);
 		ensureDoesNotExist(file);
 	}
@@ -115,7 +124,9 @@ public void testParentNotExistsShallow() {
 	}
 
 	@Test
-	public void testParentNotExistsShallowInLocalFile() {
+	public void testParentNotExistsShallowInLocalFile() throws CoreException {
+		IFileStore localFileBaseStore = localFileStoreRule.getFileStore();
+		localFileBaseStore.delete(EFS.NONE, getMonitor());
 		CoreException e = assertThrows(CoreException.class, () -> {
 			IFileStore localFileTopDir = localFileBaseStore.getChild("topDir");
 			localFileTopDir.mkdir(EFS.SHALLOW, getMonitor());
@@ -126,6 +137,8 @@ public void testParentNotExistsShallowInLocalFile() {
 
 	@Test
 	public void testTargetIsFileInLocalFile() throws Exception {
+		IFileStore localFileBaseStore = localFileStoreRule.getFileStore();
+		localFileBaseStore.delete(EFS.NONE, getMonitor());
 		CoreException e = assertThrows(CoreException.class, () -> {
 			ensureExists(localFileBaseStore, true);
 			IFileStore localFileTopDir = localFileBaseStore.getChild("topDir");

resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/filesystem/DeleteTest.java

@@ -13,21 +13,31 @@
  *******************************************************************************/
 package org.eclipse.core.tests.filesystem;
 
+import static org.eclipse.core.tests.filesystem.FileSystemTestUtil.ensureExists;
+import static org.eclipse.core.tests.filesystem.FileSystemTestUtil.getMonitor;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
 import org.eclipse.core.filesystem.EFS;
 import org.eclipse.core.filesystem.IFileStore;
+import org.eclipse.core.tests.filesystem.FileStoreCreationRule.FileSystemType;
+import org.junit.Rule;
 import org.junit.Test;
 
 /**
  * Black box testing of {@link IFileStore#delete(int, org.eclipse.core.runtime.IProgressMonitor)}.
  */
-public class DeleteTest extends FileSystemTest {
+public class DeleteTest {
+	@Rule
+	public final FileStoreCreationRule localFileStoreRule = new FileStoreCreationRule(FileSystemType.LOCAL);
+
+	@Rule
+	public final FileStoreCreationRule inMemoryFileStoreRule = new FileStoreCreationRule(FileSystemType.IN_MEMORY);
 
 	@Test
 	public void testDeleteFile() throws Exception {
+		IFileStore baseStore = inMemoryFileStoreRule.getFileStore();
 		IFileStore file = baseStore.getChild("child");
 		ensureExists(file, false);
 
@@ -38,6 +48,7 @@ public void testDeleteFile() throws Exception {
 
 	@Test
 	public void testDeleteDirectory() throws Exception {
+		IFileStore baseStore = inMemoryFileStoreRule.getFileStore();
 		IFileStore dir = baseStore.getChild("child");
 		ensureExists(dir, true);
 
@@ -48,6 +59,7 @@ public void testDeleteDirectory() throws Exception {
 
 	@Test
 	public void testDeleteReadOnlyFile() throws Exception {
+		IFileStore localFileBaseStore = localFileStoreRule.getFileStore();
 		ensureExists(localFileBaseStore, true);
 		IFileStore file = localFileBaseStore.getChild("child");
 		ensureExists(file, false);

resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/filesystem/EFSTest.java

@@ -24,7 +24,7 @@
  * Tests public API methods of the class EFS.
  * @see EFS
  */
-public class EFSTest extends FileSystemTest {
+public class EFSTest {
 	@Test
 	public void testGetLocalFileSystem() {
 		IFileSystem system = EFS.getLocalFileSystem();

resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/filesystem/FileCacheTest.java

@@ -13,6 +13,7 @@
  *******************************************************************************/
 package org.eclipse.core.tests.filesystem;
 
+import static org.eclipse.core.tests.filesystem.FileSystemTestUtil.getMonitor;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -37,7 +38,7 @@
 /**
  * Tests the file caching provided by FileStore.toLocalFile.
  */
-public class FileCacheTest extends FileSystemTest {
+public class FileCacheTest {
 
 	/**
 	 * Returns the byte[] contents of the given file.
@@ -49,16 +50,12 @@ private byte[] getBytes(File cachedFile) throws FileNotFoundException, IOExcepti
 	}
 
 	@Before
-	@Override
 	public void setUp() throws Exception {
-		super.setUp();
 		MemoryTree.TREE.deleteAll();
 	}
 
 	@After
-	@Override
 	public void tearDown() throws Exception {
-		super.tearDown();
 		MemoryTree.TREE.deleteAll();
 	}
 

resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/filesystem/FileStoreCreationRule.java

@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * Copyright (c) Vector Informatik GmbH and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ *******************************************************************************/
+package org.eclipse.core.tests.filesystem;
+
+import java.net.URI;
+import org.eclipse.core.filesystem.EFS;
+import org.eclipse.core.filesystem.IFileStore;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.tests.harness.FileSystemHelper;
+import org.eclipse.core.tests.internal.filesystem.ram.MemoryTree;
+import org.junit.rules.ExternalResource;
+
+/**
+ * A test rule for automatically creating and disposing a file store for the
+ * local file system or in memory.
+ */
+public class FileStoreCreationRule extends ExternalResource {
+	public enum FileSystemType {
+		LOCAL, IN_MEMORY
+	}
+
+	private final FileSystemType fileSystemType;
+
+	private IFileStore fileStore;
+
+	public FileStoreCreationRule(FileSystemType fileSystemType) {
+		this.fileSystemType = fileSystemType;
+	}
+
+	public IFileStore getFileStore() {
+		return fileStore;
+	}
+
+	@Override
+	protected void before() throws Throwable {
+		switch(fileSystemType) {
+		case LOCAL:
+			var fileStoreLocation = FileSystemHelper.getRandomLocation(FileSystemHelper.getTempDir());
+			fileStore = EFS.getLocalFileSystem().getStore(fileStoreLocation);
+			break;
+		case IN_MEMORY:
+			MemoryTree.TREE.deleteAll();
+			fileStore = EFS.getStore(URI.create("mem:/baseStore"));
+			break;
+		}
+		fileStore.mkdir(EFS.NONE, null);
+	}
+
+	@Override
+	protected void after() {
+		try {
+			fileStore.delete(EFS.NONE, null);
+		} catch (CoreException e) {
+		}
+		switch (fileSystemType) {
+		case IN_MEMORY:
+			MemoryTree.TREE.deleteAll();
+		}
+	}
+}