Disable metrics export in integration tests

This commit introduces a new property to globally disable metrics
export. In integration tests, this property is automatically set to
disable everything but in-memory metrics.

This commit also introduces a `@AutoConfigureMetrics` annotation that
can be used for integration tests that require metrics export to operate
as they would in an application.

See gh-21658

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/metrics/AutoConfigureMetricsMissingIntegrationTests.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2019 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.boot.test.autoconfigure.metrics;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.core.env.Environment;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration test to verify behaviour when
+ * {@link AutoConfigureMetrics @AutoConfigureMetrics} is not present on the test class.
+ *
+ * @author Chris Bono
+ */
+@SpringBootTest
+class AutoConfigureMetricsMissingIntegrationTests {
+
+	@Autowired
+	private Environment environment;
+
+	@Test
+	void customizerRunsAndSetsExclusionPropertiesWhenNoAnnotationPresent() {
+		assertThat(this.environment.getProperty("management.metrics.export.enabled")).isEqualTo("false");
+		assertThat(this.environment.getProperty("management.metrics.export.simple.enabled")).isEqualTo("true");
+	}
+
+}

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/metrics/AutoConfigureMetricsPresentIntegrationTests.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2019 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.boot.test.autoconfigure.metrics;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.core.env.Environment;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration test to verify behaviour when
+ * {@link AutoConfigureMetrics @AutoConfigureMetrics} is present on the test class.
+ *
+ * @author Chris Bono
+ */
+@SpringBootTest
+@AutoConfigureMetrics
+class AutoConfigureMetricsPresentIntegrationTests {
+
+	@Autowired
+	private Environment environment;
+
+	@Test
+	void customizerDoesNotRunWhenAnnotationPresent() {
+		assertThat(this.environment.containsProperty("management.metrics.export.enabled")).isFalse();
+		assertThat(this.environment.containsProperty("management.metrics.export.simple.enabled")).isFalse();
+	}
+
+}

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/metrics/AutoConfigureMetricsSpringBootApplication.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2012-2019 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.boot.test.autoconfigure.metrics;
+
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Example {@link SpringBootApplication @SpringBootApplication} for use with
+ * {@link AutoConfigureMetrics @AutoConfigureMetrics} tests.
+ *
+ * @author Chris Bono
+ */
+@SpringBootConfiguration
+@EnableAutoConfiguration
+class AutoConfigureMetricsSpringBootApplication {
+
+}

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/metrics/ExcludeMetricExportersContextCustomizerFactoryTests.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2012-2019 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.boot.test.autoconfigure.metrics;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.support.GenericApplicationContext;
+import org.springframework.test.context.ContextCustomizer;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link AutoConfigureMetrics} and
+ * {@link ExcludeMetricExportersContextCustomizerFactory} working together.
+ *
+ * @author Chris Bono
+ */
+class ExcludeMetricExportersContextCustomizerFactoryTests {
+
+	private ExcludeMetricExportersContextCustomizerFactory factory = new ExcludeMetricExportersContextCustomizerFactory();
+
+	@Test
+	void getContextCustomizerWhenHasNoAnnotationShouldReturnCustomizer() {
+		ContextCustomizer customizer = this.factory.createContextCustomizer(NoAnnotation.class, null);
+		assertThat(customizer).isNotNull();
+		ConfigurableApplicationContext context = new GenericApplicationContext();
+		customizer.customizeContext(context, null);
+		assertThat(context.getEnvironment().getProperty("management.metrics.export.enabled")).isEqualTo("false");
+		assertThat(context.getEnvironment().getProperty("management.metrics.export.simple.enabled")).isEqualTo("true");
+	}
+
+	@Test
+	void getContextCustomizerWhenHasAnnotationShouldReturnNull() {
+		ContextCustomizer customizer = this.factory.createContextCustomizer(WithAnnotation.class, null);
+		assertThat(customizer).isNull();
+	}
+
+	@Test
+	void hashCodeAndEquals() {
+		ContextCustomizer customizer1 = this.factory.createContextCustomizer(NoAnnotation.class, null);
+		ContextCustomizer customizer2 = this.factory.createContextCustomizer(OtherWithNoAnnotation.class, null);
+		assertThat(customizer1.hashCode()).isEqualTo(customizer2.hashCode());
+		assertThat(customizer1).isEqualTo(customizer1).isEqualTo(customizer2);
+	}
+
+	static class NoAnnotation {
+
+	}
+
+	static class OtherWithNoAnnotation {
+
+	}
+
+	@AutoConfigureMetrics
+	static class WithAnnotation {
+
+	}
+
+}