Capture process output as file attachments

platform-tests/src/processStarter/java/org/junit/platform/tests/process/OutputFiles.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright 2015-2024 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package org.junit.platform.tests.process;
+
+import java.nio.file.Path;
+
+public record OutputFiles(Path stdOut, Path stdErr) {
+}

platform-tests/src/processStarter/java/org/junit/platform/tests/process/ProcessStarter.java

@@ -15,11 +15,14 @@
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.io.UncheckedIOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.stream.Stream;
 
@@ -28,10 +31,13 @@
 
 public class ProcessStarter {
 
+	public static final Charset OUTPUT_ENCODING = Charset.forName(System.getProperty("native.encoding"));
+
 	private Path executable;
 	private Path workingDir;
 	private final List<String> arguments = new ArrayList<>();
 	private final Map<String, String> environment = new LinkedHashMap<>();
+	private Optional<OutputFiles> outputFiles = Optional.empty();
 
 	public ProcessStarter executable(Path executable) {
 		this.executable = executable;
@@ -62,6 +68,11 @@ public ProcessStarter putEnvironment(Map<String, String> values) {
 		return this;
 	}
 
+	public ProcessStarter redirectOutput(OutputFiles outputFiles) {
+		this.outputFiles = Optional.of(outputFiles);
+		return this;
+	}
+
 	public ProcessResult startAndWait() throws InterruptedException {
 		return start().waitFor();
 	}
@@ -75,8 +86,10 @@ public WatchedProcess start() {
 			}
 			builder.environment().putAll(environment);
 			var process = builder.start();
-			var out = forwardAndCaptureOutput(process, System.out, ProcessGroovyMethods::consumeProcessOutputStream);
-			var err = forwardAndCaptureOutput(process, System.err, ProcessGroovyMethods::consumeProcessErrorStream);
+			var out = forwardAndCaptureOutput(process, System.out, outputFiles.map(OutputFiles::stdOut),
+				ProcessGroovyMethods::consumeProcessOutputStream);
+			var err = forwardAndCaptureOutput(process, System.err, outputFiles.map(OutputFiles::stdErr),
+				ProcessGroovyMethods::consumeProcessErrorStream);
 			return new WatchedProcess(process, out, err);
 		}
 		catch (IOException e) {
@@ -85,10 +98,23 @@ public WatchedProcess start() {
 	}
 
 	private static WatchedOutput forwardAndCaptureOutput(Process process, PrintStream delegate,
-			BiFunction<Process, OutputStream, Thread> captureAction) {
+			Optional<Path> outputFile, BiFunction<Process, OutputStream, Thread> captureAction) {
 		var capturingStream = new ByteArrayOutputStream();
-		var thread = captureAction.apply(process, new TeeOutputStream(delegate, capturingStream));
-		return new WatchedOutput(thread, capturingStream);
+		Optional<OutputStream> fileStream = outputFile.map(path -> {
+			try {
+				return Files.newOutputStream(path);
+			}
+			catch (IOException e) {
+				throw new UncheckedIOException("Failed to open output file: " + path, e);
+			}
+		});
+		var attachedStream = tee(delegate, fileStream.map(it -> tee(capturingStream, it)).orElse(capturingStream));
+		var thread = captureAction.apply(process, attachedStream);
+		return new WatchedOutput(thread, capturingStream, fileStream);
+	}
+
+	private static OutputStream tee(OutputStream out, OutputStream branch) {
+		return new TeeOutputStream(out, branch);
 	}
 
 }

platform-tests/src/processStarter/java/org/junit/platform/tests/process/WatchedOutput.java

@@ -10,14 +10,15 @@
 
 package org.junit.platform.tests.process;
 
-import java.io.ByteArrayOutputStream;
-import java.nio.charset.Charset;
+import static org.junit.platform.tests.process.ProcessStarter.OUTPUT_ENCODING;
 
-record WatchedOutput(Thread thread, ByteArrayOutputStream stream) {
+import java.io.ByteArrayOutputStream;
+import java.io.OutputStream;
+import java.util.Optional;
 
-	private static final Charset CHARSET = Charset.forName(System.getProperty("native.encoding"));
+record WatchedOutput(Thread thread, ByteArrayOutputStream stream, Optional<OutputStream> fileStream) {
 
 	String streamAsString() {
-		return stream.toString(CHARSET);
+		return stream.toString(OUTPUT_ENCODING);
 	}
 }

platform-tests/src/processStarter/java/org/junit/platform/tests/process/WatchedProcess.java

@@ -10,6 +10,10 @@
 
 package org.junit.platform.tests.process;
 
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Optional;
+
 public class WatchedProcess {
 
 	private final Process process;
@@ -46,6 +50,19 @@ ProcessResult waitFor() throws InterruptedException {
 		}
 		finally {
 			process.destroyForcibly();
+			closeQuietly(out.fileStream());
+			closeQuietly(err.fileStream());
+		}
+	}
+
+	private static void closeQuietly(Optional<OutputStream> fileStream) {
+		if (fileStream.isEmpty()) {
+			return;
+		}
+		try {
+			fileStream.get().close();
+		}
+		catch (IOException ignore) {
 		}
 	}
 }

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/AntStarterTests.java

@@ -22,6 +22,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.platform.tests.process.OutputFiles;
 
 import platform.tooling.support.ProcessStarters;
 
@@ -32,10 +33,11 @@ class AntStarterTests {
 
 	@Test
 	@Timeout(60)
-	void ant_starter(@TempDir Path workspace) throws Exception {
+	void ant_starter(@TempDir Path workspace, @FilePrefix("ant") OutputFiles outputFiles) throws Exception {
 		var result = ProcessStarters.java() //
 				.workingDir(copyToWorkspace(Projects.ANT_STARTER, workspace)) //
 				.addArguments("-cp", System.getProperty("antJars"), Main.class.getName()) //
+				.redirectOutput(outputFiles) //
 				.startAndWait();
 
 		assertEquals(0, result.exitCode());
@@ -57,5 +59,4 @@ void ant_starter(@TempDir Path workspace) throws Exception {
 		var testResultsDir = workspace.resolve("build/test-report");
 		verifyContainsExpectedStartedOpenTestReport(testResultsDir);
 	}
-
 }

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/FilePrefix.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2015-2024 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package platform.tooling.support.tests;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.jupiter.api.extension.ExtendWith;
+
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+@ExtendWith(OutputAttachingExtension.class)
+@interface FilePrefix {
+	String value();
+}

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/GraalVmStarterTests.java

@@ -23,6 +23,7 @@
 import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
 import org.junit.jupiter.api.extension.DisabledOnOpenJ9;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.platform.tests.process.OutputFiles;
 
 import platform.tooling.support.MavenRepo;
 import platform.tooling.support.ProcessStarters;
@@ -37,12 +38,14 @@ class GraalVmStarterTests {
 
 	@Test
 	@Timeout(value = 10, unit = MINUTES)
-	void runsTestsInNativeImage(@TempDir Path workspace) throws Exception {
+	void runsTestsInNativeImage(@TempDir Path workspace, @FilePrefix("gradle") OutputFiles outputFiles)
+			throws Exception {
 		var result = ProcessStarters.gradlew() //
 				.workingDir(copyToWorkspace(Projects.GRAALVM_STARTER, workspace)) //
 				.addArguments("-Dmaven.repo=" + MavenRepo.dir()) //
 				.addArguments("javaToolchains", "nativeTest", "--no-daemon", "--stacktrace", "--no-build-cache",
 					"--warning-mode=fail") //
+				.redirectOutput(outputFiles) //
 				.startAndWait();
 
 		assertEquals(0, result.exitCode());

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/GradleKotlinExtensionsTests.java

@@ -18,6 +18,7 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.platform.tests.process.OutputFiles;
 import org.opentest4j.TestAbortedException;
 
 import platform.tooling.support.Helper;
@@ -30,12 +31,13 @@
 class GradleKotlinExtensionsTests {
 
 	@Test
-	void gradle_wrapper(@TempDir Path workspace) throws Exception {
+	void gradle_wrapper(@TempDir Path workspace, @FilePrefix("gradle") OutputFiles outputFiles) throws Exception {
 		var result = ProcessStarters.gradlew() //
 				.workingDir(copyToWorkspace(Projects.GRADLE_KOTLIN_EXTENSIONS, workspace)) //
 				.addArguments("-Dmaven.repo=" + MavenRepo.dir()) //
 				.addArguments("build", "--no-daemon", "--stacktrace", "--no-build-cache", "--warning-mode=fail") //
 				.putEnvironment("JDK8", Helper.getJavaHome("8").orElseThrow(TestAbortedException::new).toString()) //
+				.redirectOutput(outputFiles) //
 				.startAndWait();
 
 		assertEquals(0, result.exitCode(), "result=" + result);

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/GradleMissingEngineTests.java

@@ -19,6 +19,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 import org.junit.platform.reporting.testutil.FileUtils;
+import org.junit.platform.tests.process.OutputFiles;
 import org.opentest4j.TestAbortedException;
 
 import platform.tooling.support.Helper;
@@ -31,13 +32,13 @@
 class GradleMissingEngineTests {
 
 	@Test
-	void gradle_wrapper(@TempDir Path workspace) throws Exception {
+	void gradle_wrapper(@TempDir Path workspace, @FilePrefix("gradle") OutputFiles outputFiles) throws Exception {
 		var result = ProcessStarters.gradlew() //
 				.workingDir(copyToWorkspace(Projects.GRADLE_MISSING_ENGINE, workspace)) //
 				.addArguments("-Dmaven.repo=" + MavenRepo.dir()) //
 				.addArguments("build", "--no-daemon", "--stacktrace", "--no-build-cache", "--warning-mode=fail") //
 				.putEnvironment("JDK8", Helper.getJavaHome("8").orElseThrow(TestAbortedException::new).toString()) //
-				.startAndWait();
+				.redirectOutput(outputFiles).startAndWait();
 
 		assertEquals(1, result.exitCode());
 		assertThat(result.stdErrLines()) //

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/GradleStarterTests.java

@@ -20,6 +20,7 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.platform.tests.process.OutputFiles;
 import org.opentest4j.TestAbortedException;
 
 import platform.tooling.support.Helper;
@@ -32,12 +33,13 @@
 class GradleStarterTests {
 
 	@Test
-	void gradle_wrapper(@TempDir Path workspace) throws Exception {
+	void gradle_wrapper(@TempDir Path workspace, @FilePrefix("gradle") OutputFiles outputFiles) throws Exception {
 		var result = ProcessStarters.gradlew() //
 				.workingDir(copyToWorkspace(Projects.GRADLE_STARTER, workspace)) //
 				.addArguments("-Dmaven.repo=" + MavenRepo.dir()) //
 				.addArguments("build", "--no-daemon", "--stacktrace", "--no-build-cache", "--warning-mode=fail") //
 				.putEnvironment("JDK8", Helper.getJavaHome("8").orElseThrow(TestAbortedException::new).toString()) //
+				.redirectOutput(outputFiles) //
 				.startAndWait();
 
 		assertEquals(0, result.exitCode());

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/JarDescribeModuleTests.java

@@ -21,6 +21,7 @@
 import org.junit.jupiter.api.Order;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.platform.tests.process.OutputFiles;
 
 import platform.tooling.support.Helper;
 import platform.tooling.support.MavenRepo;
@@ -34,13 +35,14 @@ class JarDescribeModuleTests {
 
 	@ParameterizedTest
 	@MethodSource("platform.tooling.support.Helper#loadModuleDirectoryNames")
-	void describeModule(String module) throws Exception {
+	void describeModule(String module, @FilePrefix("jar") OutputFiles outputFiles) throws Exception {
 		var sourceDirectory = getSourceDirectory(Projects.JAR_DESCRIBE_MODULE);
 		var modulePath = MavenRepo.jar(module);
 
 		var result = ProcessStarters.javaCommand("jar") //
 				.workingDir(sourceDirectory) //
 				.addArguments("--describe-module", "--file", modulePath.toAbsolutePath().toString()) //
+				.redirectOutput(outputFiles) //
 				.startAndWait();
 
 		assertEquals(0, result.exitCode());

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/JavaVersionsTests.java

@@ -22,6 +22,7 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.platform.tests.process.OutputFiles;
 
 import platform.tooling.support.Helper;
 import platform.tooling.support.MavenRepo;
@@ -39,22 +40,22 @@ class JavaVersionsTests {
 	Path workspace;
 
 	@Test
-	void java_8() throws Exception {
+	void java_8(@FilePrefix("maven") OutputFiles outputFiles) throws Exception {
 		var java8Home = Helper.getJavaHome("8");
 		assumeTrue(java8Home.isPresent(), "Java 8 installation directory not found!");
-		var actualLines = execute(java8Home.get(), Map.of());
+		var actualLines = execute(java8Home.get(), outputFiles, Map.of());
 
 		assertTrue(actualLines.contains("[WARNING] Tests run: 2, Failures: 0, Errors: 0, Skipped: 1"));
 	}
 
 	@Test
-	void java_default() throws Exception {
-		var actualLines = execute(currentJdkHome(), MavenEnvVars.FOR_JDK24_AND_LATER);
+	void java_default(@FilePrefix("maven") OutputFiles outputFiles) throws Exception {
+		var actualLines = execute(currentJdkHome(), outputFiles, MavenEnvVars.FOR_JDK24_AND_LATER);
 
 		assertTrue(actualLines.contains("[WARNING] Tests run: 2, Failures: 0, Errors: 0, Skipped: 1"));
 	}
 
-	List<String> execute(Path javaHome, Map<String, String> environmentVars) throws Exception {
+	List<String> execute(Path javaHome, OutputFiles outputFiles, Map<String, String> environmentVars) throws Exception {
 		var result = ProcessStarters.maven(javaHome) //
 				.workingDir(copyToWorkspace(Projects.JAVA_VERSIONS, workspace)) //
 				.putEnvironment(environmentVars) //

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/MavenStarterTests.java

@@ -20,6 +20,7 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.platform.tests.process.OutputFiles;
 import org.opentest4j.TestAbortedException;
 
 import platform.tooling.support.Helper;
@@ -38,12 +39,14 @@ class MavenStarterTests {
 	MavenRepoProxy mavenRepoProxy;
 
 	@Test
-	void verifyMavenStarterProject(@TempDir Path workspace) throws Exception {
+	void verifyMavenStarterProject(@TempDir Path workspace, @FilePrefix("maven") OutputFiles outputFiles)
+			throws Exception {
 		var result = ProcessStarters.maven(Helper.getJavaHome("8").orElseThrow(TestAbortedException::new)) //
 				.workingDir(copyToWorkspace(Projects.MAVEN_STARTER, workspace)) //
 				.addArguments(localMavenRepo.toCliArgument(), "-Dmaven.repo=" + MavenRepo.dir()) //
 				.addArguments("-Dsnapshot.repo.url=" + mavenRepoProxy.getBaseUri()) //
 				.addArguments("--update-snapshots", "--batch-mode", "verify") //
+				.redirectOutput(outputFiles) //
 				.startAndWait();
 
 		assertEquals(0, result.exitCode());