[eclipse-cdt#247] Add .clangd configuration file syntax checker

- add unit tests

bundles/org.eclipse.cdt.lsp.clangd/src/org/eclipse/cdt/lsp/internal/clangd/ClangdConfigFileChecker.java

@@ -35,6 +35,9 @@ public class ClangdConfigFileChecker {
 	 * @param configFile
 	 */
 	public void checkConfigFile(IFile configFile) {
+		if (!configFile.exists()) {
+			return;
+		}
 		Yaml yaml = new Yaml();
 		try (var inputStream = configFile.getContents()) {
 			try {

tests/org.eclipse.cdt.lsp.clangd.tests/src/org/eclipse/cdt/lsp/internal/clangd/tests/ClangdConfigFileCheckerTest.java

@@ -0,0 +1,148 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Bachmann electronic GmbH and others.
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Gesa Hentschke (Bachmann electronic GmbH) - initial implementation
+ *******************************************************************************/
+
+package org.eclipse.cdt.lsp.internal.clangd.tests;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+
+import org.eclipse.cdt.lsp.clangd.ClangdConfigurationFileManager;
+import org.eclipse.cdt.lsp.clangd.tests.TestUtils;
+import org.eclipse.cdt.lsp.internal.clangd.ClangdConfigFileChecker;
+import org.eclipse.cdt.lsp.internal.clangd.ClangdConfigFileMonitor;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.NullProgressMonitor;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInfo;
+
+class ClangdConfigFileCheckerTest {
+	private static final String ERROR_MSG = ".clangd problem marker has not been added to the config file!";
+	private static final String VALID_YAML_SYNTAX = "\r\nCompileFlags: {CompilationDatabase: Release}\r\n";
+	private static final String INVALID_YAML_SYNTAX_TAB_ONLY = "\t";
+	private static final String INVALID_YAML_SYNTAX_CONTAINS_TAB = "\r\nCompileFlags:\n\tCompilationDatabase: Release";
+	private static final String INVALID_YAML_SYNTAX_MISSING_BRACE = "CompileFlags: {CompilationDatabase: Release\r\n";
+
+	private IProject project;
+
+	@BeforeEach
+	public void setUp(TestInfo testInfo) throws CoreException {
+		var projectName = TestUtils.getName(testInfo);
+		project = TestUtils.createCProject(projectName);
+	}
+
+	@AfterEach
+	public void cleanUp() throws CoreException {
+		TestUtils.deleteProject(project);
+	}
+
+	private IFile createConfigFile(String content) throws UnsupportedEncodingException, IOException, CoreException {
+		var file = project.getFile(ClangdConfigurationFileManager.CLANGD_CONFIG_FILE_NAME);
+		try (final var data = new ByteArrayInputStream(content.getBytes(project.getDefaultCharset()))) {
+			if (!file.exists()) {
+				file.create(data, false, new NullProgressMonitor());
+			} else {
+				file.setContents(data, IResource.KEEP_HISTORY, new NullProgressMonitor());
+			}
+		}
+		return file;
+	}
+
+	/**
+	 * Test valid yaml syntax. No marker should be added.
+	 *
+	 * @throws IOException
+	 * @throws CoreException
+	 */
+	@Test
+	void testValidYamlSyntax() throws IOException, CoreException {
+		// GIVEN an existing .clangd configuration file with valid yaml syntax:
+		var configFile = createConfigFile(VALID_YAML_SYNTAX);
+		// WHEN the ClangdConfigFileChecker().checkConfigFile get called on the configFile:
+		new ClangdConfigFileChecker().checkConfigFile(configFile);
+		// THEN we expect that NO ClangdConfigFileChecker.CLANGD_MARKER has been added:
+		var marker = configFile.findMarkers(ClangdConfigFileChecker.CLANGD_MARKER, false, IResource.DEPTH_ZERO);
+		assertNotNull(marker);
+		assertEquals(0, marker.length, "Expected no marker for valid yaml syntax");
+	}
+
+	/**
+	 * Test whether a .clangd yaml Problem marker will be added to the .clangd file if the file contains invalid yaml syntax (here: tab only)
+	 *
+	 * @throws IOException
+	 * @throws CoreException
+	 */
+	@Test
+	void testInvalidYamlSyntaxTabOnly() throws IOException, CoreException {
+		// GIVEN an existing .clangd configuration file with invalid yaml syntax (contains tab only):
+		var configFile = createConfigFile(INVALID_YAML_SYNTAX_TAB_ONLY);
+		// WHEN the ClangdConfigFileChecker().checkConfigFile get called on the configFile:
+		new ClangdConfigFileChecker().checkConfigFile(configFile);
+		// THEN we expect that an ClangdConfigFileChecker.CLANGD_MARKER has been added:
+		var marker = configFile.findMarkers(ClangdConfigFileChecker.CLANGD_MARKER, false, IResource.DEPTH_ZERO);
+		assertNotNull(marker);
+		assertEquals(1, marker.length, ERROR_MSG);
+	}
+
+	/**
+	 * Test whether a .clangd yaml Problem marker will be added to the .clangd file if the file contains invalid yaml syntax (here: tab)
+	 *
+	 * @throws IOException
+	 * @throws CoreException
+	 */
+	@Test
+	void testInvalidYamlSyntaxContainsTab() throws IOException, CoreException {
+		// GIVEN an existing .clangd configuration file with invalid yaml syntax (contains tab):
+		var configFile = createConfigFile(INVALID_YAML_SYNTAX_CONTAINS_TAB);
+		// WHEN the ClangdConfigFileChecker().checkConfigFile get called on the configFile:
+		new ClangdConfigFileChecker().checkConfigFile(configFile);
+		// THEN we expect that an ClangdConfigFileChecker.CLANGD_MARKER has been added:
+		var marker = configFile.findMarkers(ClangdConfigFileChecker.CLANGD_MARKER, false, IResource.DEPTH_ZERO);
+		assertNotNull(marker);
+		assertEquals(1, marker.length, ERROR_MSG);
+	}
+
+	/**
+	 * Test whether a .clangd yaml Problem marker will be added to the .clangd file if the file contains invalid yaml syntax (here: missing closing brace)
+	 * because the {@link ClangdConfigFileMonitor#checkJob} should have been run after a delay of 100ms.
+	 *
+	 * @throws IOException
+	 * @throws CoreException
+	 */
+	@Test
+	void testInvalidYamlSyntaxMissingBrace() throws IOException, CoreException {
+		// GIVEN an existing .clangd configuration file with invalid yaml syntax (missing closing brace):
+		// WHEN a new .clang file gets added to the project (should trigger ClangdConfigFileMonitor.checkJob).
+		var configFile = createConfigFile(INVALID_YAML_SYNTAX_MISSING_BRACE);
+		// AND the UI thread sleeps for 1s:
+		try {
+			Thread.sleep(1000);
+		} catch (InterruptedException e) {
+			e.printStackTrace();
+		}
+		// THEN we expect that an ClangdConfigFileChecker.CLANGD_MARKER has been added in the meantime,
+		// because the ClangdConfigFileMonitor.checkJob, which calls the ClangdConfigFileChecker().checkConfigFile, should have been run after a delay of 100ms:
+		var marker = configFile.findMarkers(ClangdConfigFileChecker.CLANGD_MARKER, false, IResource.DEPTH_ZERO);
+		assertNotNull(marker);
+		assertEquals(1, marker.length, ERROR_MSG);
+	}
+
+}