GH-1438 - Refactorings to ease implementation.

The creation of a Changes instances is now implemented in a type solely depending on an Environment to avoid a dependency to the JUnit API which – ironically – seems a bit cumbersome to test against.

Author: odrotbohm

spring-modulith-junit/src/main/java/org/springframework/modulith/junit/ChangesFactory.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.modulith.junit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.core.env.Environment;
+import org.springframework.modulith.junit.diff.FileModificationDetector;
+import org.springframework.util.Assert;
+
+/**
+ * Dedicated factory to create a {@link Changes} instance from an {@link Environment}.
+ *
+ * @author Oliver Drotbohm
+ * @since 2.1
+ */
+class ChangesFactory {
+
+	private static final Logger log = LoggerFactory.getLogger(StateStore.class);
+
+	/**
+	 * Creates a new {@link Changes} instance from an {@link Environment}.
+	 *
+	 * @param environment will never be {@literal null}.
+	 * @return will never be {@literal null}.
+	 */
+	static Changes getChanges(Environment environment) {
+
+		Assert.notNull(environment, "Environment must not be null!");
+
+		if (Boolean.TRUE == environment.getProperty("spring.modulith.test.skip-optimizations", Boolean.class)) {
+			return Changes.NONE;
+		}
+
+		// Determine detector
+		var detector = FileModificationDetector.getDetector(environment);
+		var result = Changes.of(detector.getModifiedFiles());
+
+		if (log.isInfoEnabled()) {
+
+			log.trace("Detected changes:");
+			log.trace("-----------------");
+
+			result.forEach(it -> log.info(it.toString()));
+		}
+
+		// Obtain changes
+		return result;
+	}
+}

spring-modulith-junit/src/main/java/org/springframework/modulith/junit/StateStore.java

@@ -18,11 +18,8 @@
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
 import org.junit.jupiter.api.extension.ExtensionContext.Store;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor;
 import org.springframework.core.env.StandardEnvironment;
-import org.springframework.modulith.junit.diff.FileModificationDetector;
 import org.springframework.util.Assert;
 
 /**
@@ -32,8 +29,6 @@
  */
 class StateStore {
 
-	private static final Logger log = LoggerFactory.getLogger(StateStore.class);
-
 	private final Store store;
 
 	/**
@@ -55,30 +50,13 @@ class StateStore {
 	 */
 	Changes getChanges() {
 
-		return (Changes) store.getOrComputeIfAbsent("changed-files", s -> {
+		return (Changes) store.computeIfAbsent("changed-files", __ -> {
 
 			// Lookup configuration
 			var environment = new StandardEnvironment();
 			ConfigDataEnvironmentPostProcessor.applyTo(environment);
 
-			if (Boolean.TRUE == environment.getProperty("spring.modulith.test.skip-optimizations", Boolean.class)) {
-				return Changes.NONE;
-			}
-
-			// Determine detector
-			var detector = FileModificationDetector.getDetector(environment);
-			var result = Changes.of(detector.getModifiedFiles());
-
-			if (log.isInfoEnabled()) {
-
-				log.trace("Detected changes:");
-				log.trace("-----------------");
-
-				result.forEach(it -> log.info(it.toString()));
-			}
-
-			// Obtain changes
-			return Changes.of(detector.getModifiedFiles());
+			return ChangesFactory.getChanges(environment);
 		});
 	}
 }

spring-modulith-junit/src/test/java/org/springframework/modulith/junit/ChangesFactoryUnitTests.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.modulith.junit;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.core.env.Environment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.StandardEnvironment;
+
+/**
+ * Unit tests for {@link ChangesFactory}.
+ *
+ * @author Oliver Drotbohm
+ */
+class ChangesFactoryUnitTests {
+
+	@Test // GH-31
+	void returnsNoChangesIfDisabledByProperty() {
+
+		var environment = getEnvironment(Map.of("spring.modulith.test.skip-optimizations", "true"));
+
+		assertThat(ChangesFactory.getChanges(environment)).isEqualTo(Changes.NONE);
+	}
+
+	private Environment getEnvironment(Map<String, Object> properties) {
+
+		var propertySource = new MapPropertySource("properties", properties);
+
+		var environment = new StandardEnvironment();
+		environment.getPropertySources().addFirst(propertySource);
+
+		return environment;
+	}
+}