GH-77 - Avoid exposing TestUtils to user applications.

Moved TestUtils from spring-modulith-test to spring-modulith-integration-test as it's only used there and doesn't need to be exposed to user applications.

spring-modulith-integration-test/src/test/java/com/acme/myproject/moduleB/ModuleBTest.java

@@ -24,8 +24,8 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.AutoConfigurationPackages;
 import org.springframework.boot.test.mock.mockito.MockBean;
 import org.springframework.context.ApplicationContext;
-import org.springframework.modulith.test.ApplicationModuleTest.BootstrapMode;
 import org.springframework.modulith.test.TestUtils;
+import org.springframework.modulith.test.ApplicationModuleTest.BootstrapMode;
 
 import com.acme.myproject.NonVerifyingModuleTest;
 import com.acme.myproject.moduleA.ServiceComponentA;

spring-modulith-integration-test/src/test/java/com/acme/myproject/moduleC/ModuleCTest.java

@@ -21,8 +21,8 @@ import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.mock.mockito.MockBean;
-import org.springframework.modulith.test.ApplicationModuleTest.BootstrapMode;
 import org.springframework.modulith.test.TestUtils;
+import org.springframework.modulith.test.ApplicationModuleTest.BootstrapMode;
 
 import com.acme.myproject.NonVerifyingModuleTest;
 import com.acme.myproject.moduleA.ServiceComponentA;

spring-modulith-integration-test/src/test/java/org/springframework/modulith/test/TestUtils.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2018-2022 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 org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.UnsatisfiedDependencyException;
+import org.springframework.boot.test.context.SpringBootContextLoader;
+import org.springframework.boot.test.context.SpringBootTestContextBootstrapper;
+import org.springframework.boot.test.context.assertj.AssertableApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.test.context.BootstrapContext;
+import org.springframework.test.context.CacheAwareContextLoaderDelegate;
+import org.springframework.test.context.ContextLoadException;
+import org.springframework.test.context.MergedContextConfiguration;
+import org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate;
+import org.springframework.test.context.support.DefaultBootstrapContext;
+
+/**
+ * @author Oliver Drotbohm
+ */
+public class TestUtils {
+
+	public static void assertDependencyMissing(Class<?> testClass, Class<?> expectedMissingDependency) {
+
+		CacheAwareContextLoaderDelegate delegate = new DefaultCacheAwareContextLoaderDelegate();
+		BootstrapContext bootstrapContext = new DefaultBootstrapContext(testClass, delegate);
+
+		SpringBootTestContextBootstrapper bootstrapper = new SpringBootTestContextBootstrapper();
+		bootstrapper.setBootstrapContext(bootstrapContext);
+
+		MergedContextConfiguration configuration = bootstrapper.buildMergedContextConfiguration();
+
+		AssertableApplicationContext context = AssertableApplicationContext.get(() -> {
+
+			SpringBootContextLoader loader = new SpringBootContextLoader();
+
+			try {
+
+				return (ConfigurableApplicationContext) loader.loadContext(configuration);
+
+			} catch (ContextLoadException o_O) {
+				throw asRuntimeException(o_O.getCause());
+			} catch (Exception o_O) {
+				throw asRuntimeException(o_O);
+			}
+		});
+
+		assertThat(context).hasFailed();
+
+		assertThat(context).getFailure().isInstanceOfSatisfying(UnsatisfiedDependencyException.class, it -> {
+			assertThat(it.getMostSpecificCause()).isInstanceOfSatisfying(NoSuchBeanDefinitionException.class, ex -> {
+				assertThat(ex.getBeanType()).isEqualTo(expectedMissingDependency);
+			});
+		});
+	}
+
+	private static RuntimeException asRuntimeException(Throwable o_O) {
+		return o_O instanceof RuntimeException ? (RuntimeException) o_O : new RuntimeException(o_O);
+	}
+}