Restore HealthIndicatorRegistry beans

Restore `HealthIndicatorRegistry` and `ReactiveHealthIndicatorRegistry`
auto-configured beans with a version that adapts to the new contributor
interfaces.

Closes gh-16903

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthContributorRegistryHealthIndicatorRegistryAdapter.java

@@ -0,0 +1,79 @@
+/*
+ * 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.actuate.autoconfigure.health;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.boot.actuate.health.HealthContributor;
+import org.springframework.boot.actuate.health.HealthContributorRegistry;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
+import org.springframework.boot.actuate.health.NamedContributor;
+import org.springframework.util.Assert;
+
+/**
+ * Adapter class to convert a {@link HealthContributorRegistry} to a legacy
+ * {@link HealthIndicatorRegistry}.
+ *
+ * @author Phillip Webb
+ */
+@SuppressWarnings("deprecation")
+class HealthContributorRegistryHealthIndicatorRegistryAdapter implements HealthIndicatorRegistry {
+
+	private final HealthContributorRegistry contributorRegistry;
+
+	HealthContributorRegistryHealthIndicatorRegistryAdapter(HealthContributorRegistry contributorRegistry) {
+		Assert.notNull(contributorRegistry, "ContributorRegistry must not be null");
+		this.contributorRegistry = contributorRegistry;
+	}
+
+	@Override
+	public void register(String name, HealthIndicator healthIndicator) {
+		this.contributorRegistry.registerContributor(name, healthIndicator);
+	}
+
+	@Override
+	public HealthIndicator unregister(String name) {
+		HealthContributor contributor = this.contributorRegistry.unregisterContributor(name);
+		if (contributor instanceof HealthIndicator) {
+			return (HealthIndicator) contributor;
+		}
+		return null;
+	}
+
+	@Override
+	public HealthIndicator get(String name) {
+		HealthContributor contributor = this.contributorRegistry.getContributor(name);
+		if (contributor instanceof HealthIndicator) {
+			return (HealthIndicator) contributor;
+		}
+		return null;
+	}
+
+	@Override
+	public Map<String, HealthIndicator> getAll() {
+		Map<String, HealthIndicator> all = new LinkedHashMap<String, HealthIndicator>();
+		for (NamedContributor<?> namedContributor : this.contributorRegistry) {
+			if (namedContributor.getContributor() instanceof HealthIndicator) {
+				all.put(namedContributor.getName(), (HealthIndicator) namedContributor.getContributor());
+			}
+		}
+		return all;
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthEndpointAutoConfiguration.java

@@ -20,6 +20,7 @@ import org.springframework.boot.actuate.autoconfigure.endpoint.condition.Conditi
 import org.springframework.boot.actuate.health.HealthEndpoint;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 
@@ -32,11 +33,20 @@ import org.springframework.context.annotation.Import;
  * @since 2.0.0
  */
 @Configuration(proxyBeanMethods = false)
-@EnableConfigurationProperties(HealthEndpointProperties.class)
 @ConditionalOnAvailableEndpoint(endpoint = HealthEndpoint.class)
+@EnableConfigurationProperties
 @Import({ LegacyHealthEndpointAdaptersConfiguration.class, LegacyHealthEndpointCompatibilityConfiguration.class,
 		HealthEndpointConfiguration.class, ReactiveHealthEndpointConfiguration.class,
 		HealthEndpointWebExtensionConfiguration.class, HealthEndpointReactiveWebExtensionConfiguration.class })
 public class HealthEndpointAutoConfiguration {
 
+	@Bean
+	@SuppressWarnings("deprecation")
+	HealthEndpointProperties healthEndpointProperties(HealthIndicatorProperties healthIndicatorProperties) {
+		HealthEndpointProperties healthEndpointProperties = new HealthEndpointProperties();
+		healthEndpointProperties.getStatus().getOrder().addAll(healthIndicatorProperties.getOrder());
+		healthEndpointProperties.getStatus().getHttpMapping().putAll(healthIndicatorProperties.getHttpMapping());
+		return healthEndpointProperties;
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthIndicatorProperties.java

@@ -16,9 +16,12 @@
 
 package org.springframework.boot.actuate.autoconfigure.health;
 
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.DeprecatedConfigurationProperty;
 
 /**
@@ -29,26 +32,25 @@ import org.springframework.boot.context.properties.DeprecatedConfigurationProper
  * @deprecated since 2.2.0 in favor of {@link HealthEndpointProperties}
  */
 @Deprecated
+@ConfigurationProperties(prefix = "management.health.status")
 public class HealthIndicatorProperties {
 
-	private final HealthEndpointProperties healthEndpointProperties;
+	private List<String> order = new ArrayList<>();
 
-	HealthIndicatorProperties(HealthEndpointProperties healthEndpointProperties) {
-		this.healthEndpointProperties = healthEndpointProperties;
-	}
+	private final Map<String, Integer> httpMapping = new LinkedHashMap<String, Integer>();
 
 	@DeprecatedConfigurationProperty(replacement = "management.endpoint.health.status.order")
 	public List<String> getOrder() {
-		return this.healthEndpointProperties.getStatus().getOrder();
+		return this.order;
 	}
 
-	public void setOrder(List<String> statusOrder) {
-		this.healthEndpointProperties.getStatus().setOrder(statusOrder);
+	public void setOrder(List<String> order) {
+		this.order = order;
 	}
 
 	@DeprecatedConfigurationProperty(replacement = "management.endpoint.health.status.http-mapping")
 	public Map<String, Integer> getHttpMapping() {
-		return this.healthEndpointProperties.getStatus().getHttpMapping();
+		return this.httpMapping;
 	}
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthProperties.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.actuate.autoconfigure.health;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -76,7 +77,7 @@ public abstract class HealthProperties {
 		/**
 		 * Comma-separated list of health statuses in order of severity.
 		 */
-		private List<String> order = null;
+		private List<String> order = new ArrayList<>();
 
 		/**
 		 * Mapping of health statuses to HTTP status codes. By default, registered health

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/LegacyHealthEndpointCompatibilityConfiguration.java

@@ -16,11 +16,18 @@
 
 package org.springframework.boot.actuate.autoconfigure.health;
 
+import io.micrometer.shaded.reactor.core.publisher.Mono;
+
 import org.springframework.boot.actuate.health.HealthAggregator;
+import org.springframework.boot.actuate.health.HealthContributorRegistry;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
 import org.springframework.boot.actuate.health.HealthStatusHttpMapper;
 import org.springframework.boot.actuate.health.OrderedHealthAggregator;
+import org.springframework.boot.actuate.health.ReactiveHealthContributorRegistry;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicatorRegistry;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
@@ -32,12 +39,12 @@ import org.springframework.context.annotation.Configuration;
  */
 @Configuration(proxyBeanMethods = false)
 @SuppressWarnings("deprecation")
+@EnableConfigurationProperties
 class LegacyHealthEndpointCompatibilityConfiguration {
 
 	@Bean
-	@ConfigurationProperties(prefix = "management.health.status")
-	HealthIndicatorProperties healthIndicatorProperties(HealthEndpointProperties healthEndpointProperties) {
-		return new HealthIndicatorProperties(healthEndpointProperties);
+	HealthIndicatorProperties healthIndicatorProperties() {
+		return new HealthIndicatorProperties();
 	}
 
 	@Bean
@@ -60,4 +67,25 @@ class LegacyHealthEndpointCompatibilityConfiguration {
 		return mapper;
 	}
 
+	@Bean
+	@ConditionalOnMissingBean(HealthIndicatorRegistry.class)
+	HealthContributorRegistryHealthIndicatorRegistryAdapter healthIndicatorRegistry(
+			HealthContributorRegistry healthContributorRegistry) {
+		return new HealthContributorRegistryHealthIndicatorRegistryAdapter(healthContributorRegistry);
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass(Mono.class)
+	static class LegacyReactiveHealthEndpointCompatibilityConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean(ReactiveHealthIndicatorRegistry.class)
+		ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter reactiveHealthIndicatorRegistry(
+				ReactiveHealthContributorRegistry reactiveHealthContributorRegistry) {
+			return new ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter(
+					reactiveHealthContributorRegistry);
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter.java

@@ -0,0 +1,83 @@
+/*
+ * 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.actuate.autoconfigure.health;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.boot.actuate.health.HealthContributorRegistry;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
+import org.springframework.boot.actuate.health.NamedContributor;
+import org.springframework.boot.actuate.health.ReactiveHealthContributor;
+import org.springframework.boot.actuate.health.ReactiveHealthContributorRegistry;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicatorRegistry;
+import org.springframework.util.Assert;
+
+/**
+ * Adapter class to convert a {@link HealthContributorRegistry} to a legacy
+ * {@link HealthIndicatorRegistry}.
+ *
+ * @author Phillip Webb
+ */
+@SuppressWarnings("deprecation")
+class ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter
+		implements ReactiveHealthIndicatorRegistry {
+
+	private final ReactiveHealthContributorRegistry contributorRegistry;
+
+	ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter(
+			ReactiveHealthContributorRegistry contributorRegistry) {
+		Assert.notNull(contributorRegistry, "ContributorRegistry must not be null");
+		this.contributorRegistry = contributorRegistry;
+	}
+
+	@Override
+	public void register(String name, ReactiveHealthIndicator healthIndicator) {
+		this.contributorRegistry.registerContributor(name, healthIndicator);
+	}
+
+	@Override
+	public ReactiveHealthIndicator unregister(String name) {
+		ReactiveHealthContributor contributor = this.contributorRegistry.unregisterContributor(name);
+		if (contributor instanceof ReactiveHealthIndicator) {
+			return (ReactiveHealthIndicator) contributor;
+		}
+		return null;
+	}
+
+	@Override
+	public ReactiveHealthIndicator get(String name) {
+		ReactiveHealthContributor contributor = this.contributorRegistry.getContributor(name);
+		if (contributor instanceof ReactiveHealthIndicator) {
+			return (ReactiveHealthIndicator) contributor;
+		}
+		return null;
+	}
+
+	@Override
+	public Map<String, ReactiveHealthIndicator> getAll() {
+		Map<String, ReactiveHealthIndicator> all = new LinkedHashMap<>();
+		for (NamedContributor<?> namedContributor : this.contributorRegistry) {
+			if (namedContributor.getContributor() instanceof ReactiveHealthIndicator) {
+				all.put(namedContributor.getName(), (ReactiveHealthIndicator) namedContributor.getContributor());
+			}
+		}
+		return all;
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/health/HealthContributorRegistryHealthIndicatorRegistryAdapterTests.java

@@ -0,0 +1,109 @@
+/*
+ * 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.actuate.autoconfigure.health;
+
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.health.CompositeHealthContributor;
+import org.springframework.boot.actuate.health.DefaultHealthContributorRegistry;
+import org.springframework.boot.actuate.health.HealthContributorRegistry;
+import org.springframework.boot.actuate.health.HealthIndicator;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.entry;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link HealthContributorRegistryHealthIndicatorRegistryAdapter}.
+ *
+ * @author Phillip Webb
+ */
+class HealthContributorRegistryHealthIndicatorRegistryAdapterTests {
+
+	private HealthContributorRegistry contributorRegistry = new DefaultHealthContributorRegistry();
+
+	private HealthContributorRegistryHealthIndicatorRegistryAdapter adapter = new HealthContributorRegistryHealthIndicatorRegistryAdapter(
+			this.contributorRegistry);
+
+	@Test
+	void createWhenContributorRegistryIsNullThrowsException() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> new HealthContributorRegistryHealthIndicatorRegistryAdapter(null))
+				.withMessage("ContributorRegistry must not be null");
+	}
+
+	@Test
+	void registerDelegatesToContributorRegistry() {
+		HealthIndicator healthIndicator = mock(HealthIndicator.class);
+		this.adapter.register("test", healthIndicator);
+		assertThat(this.contributorRegistry.getContributor("test")).isSameAs(healthIndicator);
+	}
+
+	@Test
+	void unregisterWhenDelegatesToContributorRegistry() {
+		HealthIndicator healthIndicator = mock(HealthIndicator.class);
+		this.contributorRegistry.registerContributor("test", healthIndicator);
+		HealthIndicator unregistered = this.adapter.unregister("test");
+		assertThat(unregistered).isSameAs(healthIndicator);
+		assertThat(this.contributorRegistry.getContributor("test")).isNull();
+	}
+
+	@Test
+	void unregisterWhenContributorRegistryResultIsNotHealthIndicatorReturnsNull() {
+		CompositeHealthContributor healthContributor = mock(CompositeHealthContributor.class);
+		this.contributorRegistry.registerContributor("test", healthContributor);
+		HealthIndicator unregistered = this.adapter.unregister("test");
+		assertThat(unregistered).isNull();
+		assertThat(this.contributorRegistry.getContributor("test")).isNull();
+	}
+
+	@Test
+	void getDelegatesToContributorRegistry() {
+		HealthIndicator healthIndicator = mock(HealthIndicator.class);
+		this.contributorRegistry.registerContributor("test", healthIndicator);
+		assertThat(this.adapter.get("test")).isSameAs(healthIndicator);
+	}
+
+	@Test
+	void getWhenContributorRegistryResultIsNotHealthIndicatorReturnsNull() {
+		CompositeHealthContributor healthContributor = mock(CompositeHealthContributor.class);
+		this.contributorRegistry.registerContributor("test", healthContributor);
+		assertThat(this.adapter.get("test")).isNull();
+	}
+
+	@Test
+	void getAllDelegatesContributorRegistry() {
+		HealthIndicator healthIndicator = mock(HealthIndicator.class);
+		this.contributorRegistry.registerContributor("test", healthIndicator);
+		Map<String, HealthIndicator> all = this.adapter.getAll();
+		assertThat(all).containsOnly(entry("test", healthIndicator));
+	}
+
+	@Test
+	void getAllWhenContributorRegistryContainsNonHealthIndicatorInstancesReturnsFilteredMap() {
+		CompositeHealthContributor healthContributor = mock(CompositeHealthContributor.class);
+		this.contributorRegistry.registerContributor("test1", healthContributor);
+		HealthIndicator healthIndicator = mock(HealthIndicator.class);
+		this.contributorRegistry.registerContributor("test2", healthIndicator);
+		Map<String, HealthIndicator> all = this.adapter.getAll();
+		assertThat(all).containsOnly(entry("test2", healthIndicator));
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/health/HealthIndicatorRegistryInjectionIntegrationTests.java

@@ -0,0 +1,92 @@
+/*
+ * 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.actuate.autoconfigure.health;
+
+import java.util.List;
+
+import io.micrometer.core.instrument.Gauge;
+import io.micrometer.core.instrument.MeterRegistry;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.autoconfigure.metrics.CompositeMeterRegistryAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
+import org.springframework.boot.actuate.health.CompositeHealthIndicator;
+import org.springframework.boot.actuate.health.HealthAggregator;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
+import org.springframework.boot.actuate.health.Status;
+import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.context.annotation.Configuration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration test to ensure that the legacy {@link HealthIndicatorRegistry} can still be
+ * injected.
+ *
+ * @author Phillip Webb
+ */
+@SuppressWarnings("deprecation")
+@SpringBootTest(webEnvironment = WebEnvironment.NONE)
+public class HealthIndicatorRegistryInjectionIntegrationTests {
+
+	// gh-18194
+
+	@Test
+	void meterRegistryBeanHasBeenConfigured(@Autowired MeterRegistry meterRegistry) {
+		assertThat(meterRegistry).isNotNull();
+		assertThat(meterRegistry.get("health").gauge()).isNotNull();
+	}
+
+	@Configuration
+	@ImportAutoConfiguration({ HealthEndpointAutoConfiguration.class, HealthContributorAutoConfiguration.class,
+			CompositeMeterRegistryAutoConfiguration.class, MetricsAutoConfiguration.class })
+	static class Config {
+
+		Config(HealthAggregator healthAggregator, HealthIndicatorRegistry healthIndicatorRegistry,
+				List<HealthIndicator> healthIndicators, MeterRegistry registry) {
+			CompositeHealthIndicator healthIndicator = new CompositeHealthIndicator(healthAggregator,
+					healthIndicatorRegistry);
+			for (int i = 0; i < healthIndicators.size(); i++) {
+				healthIndicatorRegistry.register(Integer.toString(i), healthIndicators.get(i));
+			}
+			Gauge.builder("health", healthIndicator, this::getGuageValue)
+					.description("Spring boot health indicator.  3=UP, 2=OUT_OF_SERVICE, 1=DOWN, 0=UNKNOWN")
+					.strongReference(true).register(registry);
+		}
+
+		private double getGuageValue(CompositeHealthIndicator health) {
+			Status status = health.health().getStatus();
+			switch (status.getCode()) {
+			case "UP":
+				return 3;
+			case "OUT_OF_SERVICE":
+				return 2;
+			case "DOWN":
+				return 1;
+			case "UNKNOWN":
+			default:
+				return 0;
+			}
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/health/ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapterTests.java

@@ -0,0 +1,110 @@
+/*
+ * 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.actuate.autoconfigure.health;
+
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.health.CompositeReactiveHealthContributor;
+import org.springframework.boot.actuate.health.DefaultReactiveHealthContributorRegistry;
+import org.springframework.boot.actuate.health.ReactiveHealthContributorRegistry;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.entry;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Test for
+ * {@link ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter}.
+ *
+ * @author Phillip Webb
+ */
+class ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapterTests {
+
+	private ReactiveHealthContributorRegistry contributorRegistry = new DefaultReactiveHealthContributorRegistry();
+
+	private ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter adapter = new ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter(
+			this.contributorRegistry);
+
+	@Test
+	void createWhenContributorRegistryIsNullThrowsException() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> new ReactiveHealthContributorRegistryReactiveHealthIndicatorRegistryAdapter(null))
+				.withMessage("ContributorRegistry must not be null");
+	}
+
+	@Test
+	void registerDelegatesToContributorRegistry() {
+		ReactiveHealthIndicator healthIndicator = mock(ReactiveHealthIndicator.class);
+		this.adapter.register("test", healthIndicator);
+		assertThat(this.contributorRegistry.getContributor("test")).isSameAs(healthIndicator);
+	}
+
+	@Test
+	void unregisterWhenDelegatesToContributorRegistry() {
+		ReactiveHealthIndicator healthIndicator = mock(ReactiveHealthIndicator.class);
+		this.contributorRegistry.registerContributor("test", healthIndicator);
+		ReactiveHealthIndicator unregistered = this.adapter.unregister("test");
+		assertThat(unregistered).isSameAs(healthIndicator);
+		assertThat(this.contributorRegistry.getContributor("test")).isNull();
+	}
+
+	@Test
+	void unregisterWhenContributorRegistryResultIsNotHealthIndicatorReturnsNull() {
+		CompositeReactiveHealthContributor healthContributor = mock(CompositeReactiveHealthContributor.class);
+		this.contributorRegistry.registerContributor("test", healthContributor);
+		ReactiveHealthIndicator unregistered = this.adapter.unregister("test");
+		assertThat(unregistered).isNull();
+		assertThat(this.contributorRegistry.getContributor("test")).isNull();
+	}
+
+	@Test
+	void getDelegatesToContributorRegistry() {
+		ReactiveHealthIndicator healthIndicator = mock(ReactiveHealthIndicator.class);
+		this.contributorRegistry.registerContributor("test", healthIndicator);
+		assertThat(this.adapter.get("test")).isSameAs(healthIndicator);
+	}
+
+	@Test
+	void getWhenContributorRegistryResultIsNotHealthIndicatorReturnsNull() {
+		CompositeReactiveHealthContributor healthContributor = mock(CompositeReactiveHealthContributor.class);
+		this.contributorRegistry.registerContributor("test", healthContributor);
+		assertThat(this.adapter.get("test")).isNull();
+	}
+
+	@Test
+	void getAllDelegatesContributorRegistry() {
+		ReactiveHealthIndicator healthIndicator = mock(ReactiveHealthIndicator.class);
+		this.contributorRegistry.registerContributor("test", healthIndicator);
+		Map<String, ReactiveHealthIndicator> all = this.adapter.getAll();
+		assertThat(all).containsOnly(entry("test", healthIndicator));
+	}
+
+	@Test
+	void getAllWhenContributorRegistryContainsNonHealthIndicatorInstancesReturnsFilteredMap() {
+		CompositeReactiveHealthContributor healthContributor = mock(CompositeReactiveHealthContributor.class);
+		this.contributorRegistry.registerContributor("test1", healthContributor);
+		ReactiveHealthIndicator healthIndicator = mock(ReactiveHealthIndicator.class);
+		this.contributorRegistry.registerContributor("test2", healthIndicator);
+		Map<String, ReactiveHealthIndicator> all = this.adapter.getAll();
+		assertThat(all).containsOnly(entry("test2", healthIndicator));
+	}
+
+}