Add tests for auto-configuration fro micrometer support

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/FeignClientsMicrometerAutoConfigurationTests.java

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+/*
+ * Copyright 2022-2022 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.cloud.openfeign;
+
+import feign.micrometer.MicrometerCapability;
+import feign.micrometer.MicrometerObservationCapability;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.observation.ObservationAutoConfiguration;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.FilteredClassLoader;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Micrometer auto-configuration tests for {@link FeignClientsConfiguration}.
+ *
+ * @author Jonatan Ivanov
+ */
+class FeignClientsMicrometerAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().withConfiguration(
+			AutoConfigurations.of(ObservationAutoConfiguration.class, SimpleMetricsExportAutoConfiguration.class,
+					MetricsAutoConfiguration.class, FeignClientsConfiguration.class));
+
+	@Test
+	void shouldProvideMicrometerObservationCapability() {
+		contextRunner.run(context -> assertThat(context).hasSingleBean(MicrometerObservationCapability.class)
+				.doesNotHaveBean(MicrometerCapability.class));
+	}
+
+	@Test
+	void shouldNotProvideMicrometerObservationCapabilityIfFeatureIsDisabled() {
+		contextRunner.withPropertyValues("spring.cloud.openfeign.micrometer.enabled=false")
+				.run(context -> assertThat(context).doesNotHaveBean(MicrometerObservationCapability.class)
+						.doesNotHaveBean(MicrometerCapability.class));
+	}
+
+	@Test
+	void shouldProvideMicrometerCapabilityIfObservationRegistryIsMissing() {
+		new ApplicationContextRunner()
+				.withConfiguration(AutoConfigurations.of(SimpleMetricsExportAutoConfiguration.class,
+						MetricsAutoConfiguration.class, FeignClientsConfiguration.class))
+				.run(context -> assertThat(context).doesNotHaveBean(MicrometerObservationCapability.class)
+						.hasSingleBean(MicrometerCapability.class));
+	}
+
+	@Test
+	void shouldProvideMicrometerCapabilityIfMicrometerObservationCapabilityIsNotOnClasspath() {
+		contextRunner.withClassLoader(new FilteredClassLoader(MicrometerObservationCapability.class))
+				.run(context -> assertThat(context).doesNotHaveBean(MicrometerObservationCapability.class)
+						.hasSingleBean(MicrometerCapability.class));
+	}
+
+	@Test
+	void shouldNotProvideMicrometerCapabilitiesIfMicrometerSupportIsMissing() {
+		contextRunner.withClassLoader(new FilteredClassLoader("feign.micrometer")).run(context -> assertThat(context)
+				.doesNotHaveBean(MicrometerObservationCapability.class).doesNotHaveBean(MicrometerCapability.class));
+	}
+
+	@Test
+	void shouldNotProvideMicrometerCapabilitiesIfBeansAreMissing() {
+		new ApplicationContextRunner().withConfiguration(AutoConfigurations.of(FeignClientsConfiguration.class))
+				.run(context -> assertThat(context).doesNotHaveBean(MicrometerObservationCapability.class)
+						.doesNotHaveBean(MicrometerCapability.class));
+	}
+
+}