Add tests for all DND transfer types

The individual Transfer types had no automatic testing, so this commit
provides tests for all the transfer types and ensures copy/paste
to external to SWT works too by implementing flavors for all types
in the Swing remote clipboard test app.

Part of #2126

Author: jonahgraham

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/AllNonBrowserTests.java

@@ -43,7 +43,14 @@
 		Test_org_eclipse_swt_accessibility_AccessibleControlEvent.class, //
 		Test_org_eclipse_swt_accessibility_AccessibleEvent.class, //
 		Test_org_eclipse_swt_accessibility_AccessibleTextEvent.class, //
-		Test_org_eclipse_swt_dnd_Clipboard.class,
+		Test_org_eclipse_swt_dnd_ByteArrayTransfer.class, //
+		Test_org_eclipse_swt_dnd_Clipboard.class, //
+		Test_org_eclipse_swt_dnd_FileTransfer.class, //
+		Test_org_eclipse_swt_dnd_HTMLTransfer.class, //
+		Test_org_eclipse_swt_dnd_ImageTransfer.class, //
+		Test_org_eclipse_swt_dnd_RTFTransfer.class, //
+		Test_org_eclipse_swt_dnd_TextTransfer.class, //
+		Test_org_eclipse_swt_dnd_URLTransfer.class, //
 		Test_org_eclipse_swt_events_ArmEvent.class, //
 		Test_org_eclipse_swt_events_ControlEvent.class, //
 		Test_org_eclipse_swt_events_DisposeEvent.class, //

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/ClipboardBase.java

@@ -31,6 +31,8 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
+import clipboard.ClipboardTest;
+
 /**
  * Base class for tests that test clipboard and transfer types
  */
@@ -178,6 +180,28 @@ public void tearDown() throws Exception {
 		}
 	}
 
+	protected String addTrailingNulCharacter(String result) {
+		return result + '\0';
+	}
+
+	/**
+	 * Trim trailing nul character - some transfer types require a trailing nul when
+	 * copied to the clipboard, so use this method to remove it for tests that
+	 * obtain bytes from the {@link ClipboardTest} app.
+	 *
+	 * @param result to trim terminating nul character from
+	 * @return string with the nul character trimmed, or null if result was null.
+	 */
+	protected String trimTrailingNulCharacter(String result) {
+		if (result == null) {
+			return null;
+		}
+		if (result.charAt(result.length() - 1) == '\0') {
+			result = result.substring(0, result.length() - 1);
+		}
+		return result;
+	}
+
 	/**
 	 * Make sure to always copy/paste unique strings - this ensures that tests run
 	 * under {@link RepeatedTest}s don't false pass because of clipboard value on

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/RemoteClipboard.java

@@ -106,7 +106,13 @@ private int launchRemote() throws IOException {
 				"ClipboardTest", //
 				"ClipboardCommands", //
 				"ClipboardCommandsImpl", //
-				"ClipboardTest$LocalHostOnlySocketFactory" //
+				"ClipboardTest$LocalHostOnlySocketFactory", //
+				"FileListSelection", //
+				"HtmlSelection", //
+				"ImageSelection", //
+				"MyTypeSelection", //
+				"RtfSelection", //
+				"UrlSelection" //
 		).forEach((f) -> {
 			// extract the files and put them in the temp directory
 			SwtTestUtil.copyFile("/clipboard/" + f + ".class",
@@ -141,6 +147,9 @@ private int launchRemote() throws IOException {
 
 	@Override
 	public void stop() throws RemoteException {
+		if (DEBUG_REMOTE) {
+			return;
+		}
 		try {
 			stopProcess();
 		} catch (InterruptedException e) {
@@ -197,6 +206,11 @@ public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOEx
 		}
 	}
 
+	@Override
+	public void setContents(String string) throws RemoteException {
+		setContents(string, CLIPBOARD);
+	}
+
 	@Override
 	public void setContents(String string, int clipboardId) throws RemoteException {
 		remote.setContents(string, clipboardId);
@@ -207,6 +221,11 @@ public void setFocus() throws RemoteException {
 		remote.setFocus();
 	}
 
+	@Override
+	public String getStringContents() throws RemoteException {
+		return getStringContents(CLIPBOARD);
+	}
+
 	@Override
 	public String getStringContents(int clipboardId) throws RemoteException {
 		return remote.getStringContents(clipboardId);
@@ -221,4 +240,65 @@ public void waitUntilReady() throws RemoteException {
 	public void waitForButtonPress() throws RemoteException {
 		remote.waitForButtonPress();
 	}
-}
+
+	@Override
+	public void setRtfContents(String test) throws RemoteException {
+		remote.setRtfContents(test);
+	}
+
+	@Override
+	public String getRtfContents() throws RemoteException {
+		return remote.getRtfContents();
+	}
+
+	@Override
+	public void setHtmlContents(String test) throws RemoteException {
+		remote.setHtmlContents(test);
+	}
+
+	@Override
+	public String getHtmlContents() throws RemoteException {
+		return remote.getHtmlContents();
+	}
+
+	@Override
+	public void setUrlContents(byte[] test) throws RemoteException {
+		remote.setUrlContents(test);
+	}
+
+	@Override
+	public byte[] getUrlContents() throws RemoteException {
+		return remote.getUrlContents();
+	}
+
+	@Override
+	public void setImageContents(byte[] imageContents) throws RemoteException {
+		remote.setImageContents(imageContents);
+	}
+
+	@Override
+	public byte[] getImageContents() throws RemoteException {
+		return remote.getImageContents();
+	}
+
+	@Override
+	public void setFileListContents(String[] fileList) throws RemoteException {
+		remote.setFileListContents(fileList);
+	}
+
+	@Override
+	public String[] getFileListContents() throws RemoteException {
+		return remote.getFileListContents();
+	}
+
+	@Override
+	public void setMyTypeContents(byte[] bytes) throws RemoteException {
+		remote.setMyTypeContents(bytes);
+	}
+
+	@Override
+	public byte[] getMyTypeContents() throws RemoteException {
+		return remote.getMyTypeContents();
+	}
+
+}