GH-165 - Introduce ScenarioCustomizer extension.

We now provide a ScenarioCustomizer that can be used to prepare Scenario instances for test methods with a common customizer. This avoids the need to call ….customize(…) for all Scenarios declared in a test class with the same logic.

spring-modulith-test/src/test/java/org/springframework/modulith/test/ScenarioCustomizerIntegrationTests.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2023 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.test;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.lang.reflect.Method;
+import java.util.function.Function;
+
+import org.awaitility.core.ConditionFactory;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.modulith.test.ScenarioCustomizerIntegrationTests.TestScenarioCustomizer;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.util.ReflectionTestUtils;
+import org.springframework.transaction.support.TransactionTemplate;
+
+/**
+ * Integration tests for {@link ScenarioCustomizer}.
+ *
+ * @author Oliver Drotbohm
+ */
+@ExtendWith({ SpringExtension.class, ScenarioParameterResolver.class, TestScenarioCustomizer.class })
+@ContextConfiguration
+class ScenarioCustomizerIntegrationTests {
+
+	@Configuration
+	static class TestConfiguration {
+
+		@Bean
+		TransactionTemplate transactionTemplate() {
+			return mock(TransactionTemplate.class);
+		}
+	}
+
+	@BeforeEach
+	void setUp() {
+		TestScenarioCustomizer.invoked = false;
+	}
+
+	@Test // GH-165
+	void customizerGetsAppliedForScenarioParameter(Scenario scenario) {
+
+		assertThat(TestScenarioCustomizer.invoked).isTrue();
+		assertThat(ReflectionTestUtils.getField(scenario, "defaultCustomizer"))
+				.isSameAs(TestScenarioCustomizer.SAMPLE);
+	}
+
+	@Test // GH-165
+	void customizerDoesNotGetAppliedForNoScenarioParameter() {
+		assertThat(TestScenarioCustomizer.invoked).isFalse();
+	}
+
+	static class TestScenarioCustomizer implements ScenarioCustomizer {
+
+		static Function<ConditionFactory, ConditionFactory> SAMPLE = it -> it;
+		static boolean invoked = false;
+
+		@Override
+		public Function<ConditionFactory, ConditionFactory> getDefaultCustomizer(Method method,
+				ApplicationContext context) {
+
+			invoked = true;
+
+			return SAMPLE;
+		}
+	}
+}

spring-modulith-test/src/test/java/org/springframework/modulith/test/ScenarioUnitTests.java

@@ -25,8 +25,10 @@ import java.lang.Thread.UncaughtExceptionHandler;
 import java.time.Duration;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.function.Supplier;
 
+import org.awaitility.core.ConditionFactory;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -347,6 +349,39 @@ class ScenarioUnitTests {
 				.getTransaction(argThat(it -> it.getPropagationBehavior() == TransactionDefinition.PROPAGATION_REQUIRES_NEW));
 	}
 
+	@Test // GH-165
+	void chainsSpecialCustomizerBehindDefaultOne() {
+
+		var defaultCustomizer = new InvocationTracingCustomizer();
+		var specialCustomizer = new InvocationTracingCustomizer();
+
+		new Scenario(tx, publisher, new DefaultAssertablePublishedEvents())
+				.setDefaultCustomizer(defaultCustomizer)
+				.publish(new Object())
+				.customize(specialCustomizer)
+				.andWaitForStateChange(() -> true);
+
+		assertThat(defaultCustomizer.invoked).isTrue();
+		assertThat(specialCustomizer.invoked).isTrue();
+	}
+
+	@Test // GH-165
+	void replacesSpecialCustomizerBehindDefaultOne() {
+
+		var defaultCustomizer = new InvocationTracingCustomizer();
+		var specialCustomizer = new InvocationTracingCustomizer();
+
+		new Scenario(tx, publisher, new DefaultAssertablePublishedEvents())
+				.setDefaultCustomizer(defaultCustomizer)
+				.publish(new Object())
+				.customize(specialCustomizer)
+				.customize(Function.identity())
+				.andWaitForStateChange(() -> true);
+
+		assertThat(defaultCustomizer.invoked).isTrue();
+		assertThat(specialCustomizer.invoked).isFalse();
+	}
+
 	private Fixture givenAScenario(Consumer<Scenario> consumer) {
 		return new Fixture(consumer, DELAY, null, new DefaultAssertablePublishedEvents());
 	}
@@ -467,4 +502,17 @@ class ScenarioUnitTests {
 			throw new RuntimeException(caught);
 		}
 	}
+
+	static class InvocationTracingCustomizer implements Function<ConditionFactory, ConditionFactory> {
+
+		boolean invoked = false;
+
+		@Override
+		public ConditionFactory apply(ConditionFactory t) {
+
+			invoked = true;
+
+			return t;
+		}
+	}
 }