Excavator: Migrate Groovy nebula test PalantirJavaFormatSpotlessPluginTest to the new Java Junit framework

Author: svc-excavator-bot

gradle-palantir-java-format/src/test/groovy/com/palantir/javaformat/gradle/PalantirJavaFormatSpotlessPluginTest.groovy

@@ -0,0 +1,102 @@
+/*
+ * (c) Copyright 2025 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.palantir.javaformat.gradle;
+
+import com.palantir.javaformat.gradle.spotless.PalantirJavaFormatStep;
+import com.palantir.javaformat.java.Formatter;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import nebula.test.IntegrationTestKitSpec;
+import nebula.test.functional.internal.classpath.ClasspathAddingInitScriptBuilder;
+import org.gradle.testkit.runner.internal.PluginUnderTestMetadataReading;
+
+/**
+ * {@link IntegrationTestKitSpec} currently loads <a href="https://github.com/nebula-plugins/nebula-test/blob/c5d3af9004898276bde5c68da492c6b0b4c5facc/src/main/groovy/nebula/test/IntegrationTestKitBase.groovy#L136"> more than what it needs into the classpath</a>.
+ * This means if we run a test with {@link IntegrationTestKitSpec}'s runner, the {@link Formatter} is on the build's classpath by virtue of being in the test's classpath.
+ * If the test applies the {@link PalantirJavaFormatPlugin}, it complains that the {@link Formatter} is <a href="https://github.com/palantir/palantir-java-format/blob/00b08d2f471d66382d6c4cd2d05f56b6bb546ad3/gradle-palantir-java-format/src/main/java/com/palantir/javaformat/gradle/spotless/PalantirJavaFormatStep.java#L83">erroneously loadable</a>.
+ * To be clear, this complaint is entirely a result of the {@link IntegrationTestKitSpec} loading too many things onto classpath since it doesn't know what the exact plugin classpath is.
+ * As a workaround, this runner uses the classpath produced by Gradle Test Kit in {@code plugin-under-test-metadata.properties}.
+ * This classpath only contains the dependencies required by the plugin, as well as the plugin itself.
+ * This means that even if we put the formatter on the {@code testClassPath}, it won't leak through to the Gradle build under test and subsequently no error from {@link PalantirJavaFormatStep}.
+ */
+public class GradlewExecutor {
+    private File projectDir;
+
+    public GradlewExecutor(File projectDir) {
+        this.projectDir = projectDir;
+    }
+
+    private static List<File> getBuildPluginClasspathInjector() {
+        return PluginUnderTestMetadataReading.readImplementationClasspath();
+    }
+
+    public GradlewExecutionResult runGradlewTasks(String... tasks) {
+        try {
+            ProcessBuilder processBuilder = getProcessBuilder(tasks);
+            Process process = processBuilder.start();
+            String output = readAllInput(process.getInputStream());
+            process.waitFor(1, TimeUnit.MINUTES);
+            return new GradlewExecutionResult(process.exitValue(), output);
+        } catch (InterruptedException | IOException e) {
+            return new GradlewExecutionResult(-1, "", e);
+        }
+    }
+
+    private static String readAllInput(InputStream inputStream) {
+        try {
+            Stream<String> lines =
+                    new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8)).lines();
+            return lines.collect(Collectors.joining("\n"));
+        } catch (Exception e) {
+            throw new RuntimeException("GradlewExecutor failed to readAllInput", e);
+        }
+    }
+
+    private ProcessBuilder getProcessBuilder(String... tasks) {
+        File initScript = new File(projectDir, "init.gradle");
+        ClasspathAddingInitScriptBuilder.build(initScript, getBuildPluginClasspathInjector());
+
+        List<String> arguments = Stream.concat(
+                        Stream.of(
+                                "./gradlew",
+                                "--init-script",
+                                initScript.toPath().toString()),
+                        Arrays.stream(tasks))
+                .toList();
+
+        return new ProcessBuilder().command(arguments).directory(projectDir).redirectErrorStream(true);
+    }
+
+    public record GradlewExecutionResult(boolean success, String standardOutput, Optional<Throwable> failure) {
+        public GradlewExecutionResult(int exitValue, String output, Throwable failure) {
+            this(exitValue == 0, output, Optional.of(failure));
+        }
+
+        public GradlewExecutionResult(int exitValue, String output) {
+            this(exitValue == 0, output, Optional.empty());
+        }
+    }
+}