chore: add test to verify execution layout

Author: simschla

app/src/test/java/com/diffplug/spotless/cli/core/ExecutionLayoutTest.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2025 DiffPlug
+ *
+ * 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.diffplug.spotless.cli.core;
+
+import java.nio.file.Path;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import com.diffplug.spotless.ResourceHarness;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ExecutionLayoutTest extends ResourceHarness {
+
+    @Test
+    void itResolvesGradleBuildDir() {
+        setFile("settings.gradle").toLines("rootProject.name = 'test'");
+        ExecutionLayout layout = ExecutionLayout.create(fileResolver(), commandLineStream());
+
+        Path buildDir = layout.buildDir();
+
+        assertThat(buildDir.toString())
+                .matches("\\Q%s\\E.*\\Q%s\\E.*"
+                        .formatted(
+                                rootFolder().toPath().toString(),
+                                Path.of("build", "spotless-cli").toString()));
+    }
+
+    @Test
+    void itResolvesMavenBuildDir() {
+        setFile("pom.xml").toLines("<project><modelVersion>4.0.0</modelVersion></project>");
+        ExecutionLayout layout = ExecutionLayout.create(fileResolver(), commandLineStream());
+
+        Path buildDir = layout.buildDir();
+
+        assertThat(buildDir.toString())
+                .matches("\\Q%s\\E.*\\Q%s\\E.*"
+                        .formatted(
+                                rootFolder().toPath().toString(),
+                                Path.of("target", "spotless-cli").toString()));
+    }
+
+    @Test
+    void itResolvesTmpBuildDir() {
+        ExecutionLayout layout = ExecutionLayout.create(fileResolver(), commandLineStream());
+
+        Path buildDir = layout.buildDir();
+
+        assertThat(buildDir.toString())
+                .doesNotStartWith(rootFolder().toPath().toString())
+                .startsWith(System.getProperty("java.io.tmpdir"));
+    }
+
+    private FileResolver fileResolver() {
+        return new FileResolver(rootFolder().toPath());
+    }
+
+    private SpotlessCommandLineStream commandLineStream() {
+        return Mockito.mock(SpotlessCommandLineStream.class);
+    }
+}

build-logic/src/main/groovy/buildlogic.java-common-conventions.gradle

@@ -9,6 +9,7 @@ plugins {
 	id 'java'
 	id 'buildlogic.spotless-java-conventions'
 	id 'buildlogic.java-selfie-tests-conventions'
+	id 'buildlogic.java-test-mockito-conventions'
 }
 
 repositories {

build-logic/src/main/groovy/buildlogic.java-test-mockito-conventions.gradle

@@ -0,0 +1,17 @@
+plugins {
+	id 'java'
+}
+
+configurations {
+	mockitoAgent
+}
+dependencies {
+	testImplementation(libs.mockito)
+	mockitoAgent(libs.mockito) {
+		transitive = false
+	}
+}
+
+tasks.withType(Test).configureEach { Test task ->
+	task.jvmArgs("-javaagent:${configurations.mockitoAgent.asPath}")
+}

gradle/libs.versions.toml

@@ -4,6 +4,7 @@ assertj-core = "3.27.3"
 diff-utils = "1.3.0"
 durian = "1.2.0"
 junit = "5.8.1"
+mockito = "5.17.0"
 native-include-googleJavaFormat = "1.24.0"
 picocli = "4.7.6"
 selfie = "2.5.1"
@@ -19,6 +20,7 @@ durian-io = { module = "com.diffplug.durian:durian-io", version.ref = "durian" }
 durian-collect = { module = "com.diffplug.durian:durian-collect", version.ref = "durian" }
 junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit" }
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit" }
+mockito = { module = "org.mockito:mockito-core", version.ref = "mockito" }
 native-include-googleJavaFormat = { module = "com.google.googlejavaformat:google-java-format", version.ref = "native-include-googleJavaFormat" }
 picocli = { module = "info.picocli:picocli", version.ref = "picocli" }
 picocli-codegen = { module = "info.picocli:picocli-codegen", version.ref = "picocli" }
@@ -34,4 +36,4 @@ native-includes = [
     "native-include-googleJavaFormat"
 ]
 spotless-libs = ["spotless-lib", "spotless-lib-extra"]
-test-libs = ["assertj-core", "junit-jupiter-api", "selfie"]
+test-libs = ["assertj-core", "junit-jupiter-api", "selfie", "mockito"]