Add health indicator for Cassandra that uses the CqlSession

This commit provides a CassandraDriverHealthIndicator and
CassandraDriverReactiveHealthIndicator that do not require Spring Data.
As a result, a health indicator for Cassandra is provided even if the
application does not use Spring Data.

See gh-20887

spring-boot-project/spring-boot-actuator-autoconfigure/build.gradle

@@ -31,6 +31,7 @@ dependencies {
 
 	optional(platform(project(":spring-boot-project:spring-boot-dependencies")))
 	optional("ch.qos.logback:logback-classic")
+	optional("com.datastax.oss:java-driver-core")
 	optional("com.fasterxml.jackson.dataformat:jackson-dataformat-xml")
 	optional("com.github.ben-manes.caffeine:caffeine")
 	optional("com.hazelcast:hazelcast")

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/cassandra/CassandraDriverHealthContributorAutoConfiguration.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2012-2020 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.cassandra;
+
+import java.util.Map;
+
+import com.datastax.oss.driver.api.core.CqlSession;
+
+import org.springframework.boot.actuate.autoconfigure.health.CompositeHealthContributorConfiguration;
+import org.springframework.boot.actuate.autoconfigure.health.ConditionalOnEnabledHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraDriverHealthIndicator;
+import org.springframework.boot.actuate.health.HealthContributor;
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * {@link EnableAutoConfiguration Auto-configuration} for
+ * {@link CassandraDriverHealthIndicator}.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass(CqlSession.class)
+@ConditionalOnBean(CqlSession.class)
+@ConditionalOnEnabledHealthIndicator("cassandra")
+@AutoConfigureAfter({ CassandraAutoConfiguration.class, CassandraReactiveHealthContributorAutoConfiguration.class,
+		CassandraHealthContributorAutoConfiguration.class,
+		CassandraDriverReactiveHealthContributorAutoConfiguration.class })
+public class CassandraDriverHealthContributorAutoConfiguration
+		extends CompositeHealthContributorConfiguration<CassandraDriverHealthIndicator, CqlSession> {
+
+	@Bean
+	@ConditionalOnMissingBean(name = { "cassandraHealthIndicator", "cassandraHealthContributor" })
+	public HealthContributor cassandraHealthContributor(Map<String, CqlSession> sessions) {
+		return createContributor(sessions);
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/cassandra/CassandraDriverReactiveHealthContributorAutoConfiguration.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2012-2020 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.cassandra;
+
+import java.util.Map;
+
+import com.datastax.oss.driver.api.core.CqlSession;
+import reactor.core.publisher.Flux;
+
+import org.springframework.boot.actuate.autoconfigure.health.CompositeReactiveHealthContributorConfiguration;
+import org.springframework.boot.actuate.autoconfigure.health.ConditionalOnEnabledHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraDriverReactiveHealthIndicator;
+import org.springframework.boot.actuate.health.ReactiveHealthContributor;
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * {@link EnableAutoConfiguration Auto-configuration} for
+ * {@link CassandraDriverReactiveHealthIndicator}.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass({ CqlSession.class, Flux.class })
+@ConditionalOnBean(CqlSession.class)
+@ConditionalOnEnabledHealthIndicator("cassandra")
+@AutoConfigureAfter({ CassandraAutoConfiguration.class, CassandraReactiveHealthContributorAutoConfiguration.class,
+		CassandraHealthContributorAutoConfiguration.class })
+public class CassandraDriverReactiveHealthContributorAutoConfiguration
+		extends CompositeReactiveHealthContributorConfiguration<CassandraDriverReactiveHealthIndicator, CqlSession> {
+
+	@Bean
+	@ConditionalOnMissingBean(name = { "cassandraHealthIndicator", "cassandraHealthContributor" })
+	public ReactiveHealthContributor cassandraHealthContributor(Map<String, CqlSession> sessions) {
+		return createContributor(sessions);
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -7,6 +7,8 @@ org.springframework.boot.actuate.autoconfigure.beans.BeansEndpointAutoConfigurat
 org.springframework.boot.actuate.autoconfigure.cache.CachesEndpointAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.cassandra.CassandraHealthContributorAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.cassandra.CassandraReactiveHealthContributorAutoConfiguration,\
+org.springframework.boot.actuate.autoconfigure.cassandra.CassandraDriverHealthContributorAutoConfiguration,\
+org.springframework.boot.actuate.autoconfigure.cassandra.CassandraDriverReactiveHealthContributorAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.cloudfoundry.servlet.CloudFoundryActuatorAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.cloudfoundry.reactive.ReactiveCloudFoundryActuatorAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.condition.ConditionsReportEndpointAutoConfiguration,\

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cassandra/CassandraDriverHealthContributorAutoConfigurationTests.java

@@ -0,0 +1,89 @@
+/*
+ * 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.cassandra;
+
+import com.datastax.oss.driver.api.core.CqlSession;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.autoconfigure.health.HealthContributorAutoConfiguration;
+import org.springframework.boot.actuate.cassandra.CassandraDriverHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraDriverReactiveHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraReactiveHealthIndicator;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.data.cassandra.core.CassandraOperations;
+import org.springframework.data.cassandra.core.ReactiveCassandraOperations;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link CassandraDriverHealthContributorAutoConfiguration}.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+class CassandraDriverHealthContributorAutoConfigurationTests {
+
+	private ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withBean(CqlSession.class, () -> mock(CqlSession.class)).withConfiguration(AutoConfigurations.of(
+					CassandraDriverHealthContributorAutoConfiguration.class, HealthContributorAutoConfiguration.class));
+
+	@Test
+	void runShouldCreateDriverIndicator() {
+		this.contextRunner.run((context) -> assertThat(context).hasSingleBean(CassandraDriverHealthIndicator.class)
+				.hasBean("cassandraHealthContributor").doesNotHaveBean(CassandraHealthIndicator.class)
+				.doesNotHaveBean(CassandraReactiveHealthIndicator.class)
+				.doesNotHaveBean(CassandraDriverReactiveHealthIndicator.class));
+	}
+
+	@Test
+	void runWhenDisabledShouldNotCreateDriverIndicator() {
+		this.contextRunner.withPropertyValues("management.health.cassandra.enabled:false")
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverHealthIndicator.class)
+						.doesNotHaveBean("cassandraHealthContributor"));
+	}
+
+	@Test
+	void runWhenSpringDataPresentShouldNotCreateDriverIndicator() {
+		this.contextRunner.withConfiguration(AutoConfigurations.of(CassandraHealthContributorAutoConfiguration.class))
+				.withBean(CassandraOperations.class, () -> mock(CassandraOperations.class))
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverHealthIndicator.class)
+						.hasSingleBean(CassandraHealthIndicator.class).hasBean("cassandraHealthContributor"));
+	}
+
+	@Test
+	void runWhenReactorPresentShouldNotCreateDriverIndicator() {
+		this.contextRunner
+				.withConfiguration(
+						AutoConfigurations.of(CassandraDriverReactiveHealthContributorAutoConfiguration.class))
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverHealthIndicator.class)
+						.hasSingleBean(CassandraDriverReactiveHealthIndicator.class)
+						.hasBean("cassandraHealthContributor"));
+	}
+
+	@Test
+	void runWhenSpringDataAndReactorPresentShouldNotCreateDriverIndicator() {
+		this.contextRunner
+				.withConfiguration(AutoConfigurations.of(CassandraReactiveHealthContributorAutoConfiguration.class))
+				.withBean(ReactiveCassandraOperations.class, () -> mock(ReactiveCassandraOperations.class))
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverHealthIndicator.class)
+						.hasSingleBean(CassandraReactiveHealthIndicator.class).hasBean("cassandraHealthContributor"));
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cassandra/CassandraDriverReactiveHealthContributorAutoConfigurationTests.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.cassandra;
+
+import com.datastax.oss.driver.api.core.CqlSession;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.autoconfigure.health.HealthContributorAutoConfiguration;
+import org.springframework.boot.actuate.cassandra.CassandraDriverReactiveHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraHealthIndicator;
+import org.springframework.boot.actuate.cassandra.CassandraReactiveHealthIndicator;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.data.cassandra.core.CassandraOperations;
+import org.springframework.data.cassandra.core.ReactiveCassandraOperations;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link CassandraDriverReactiveHealthContributorAutoConfiguration}.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+class CassandraDriverReactiveHealthContributorAutoConfigurationTests {
+
+	private ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withBean(CqlSession.class, () -> mock(CqlSession.class))
+			.withConfiguration(AutoConfigurations.of(CassandraDriverReactiveHealthContributorAutoConfiguration.class,
+					HealthContributorAutoConfiguration.class));
+
+	@Test
+	void runShouldCreateDriverReactiveIndicator() {
+		this.contextRunner
+				.run((context) -> assertThat(context).hasSingleBean(CassandraDriverReactiveHealthIndicator.class)
+						.hasBean("cassandraHealthContributor").doesNotHaveBean(CassandraHealthIndicator.class)
+						.doesNotHaveBean(CassandraReactiveHealthIndicator.class));
+	}
+
+	@Test
+	void runWhenDisabledShouldNotCreateDriverReactiveIndicator() {
+		this.contextRunner.withPropertyValues("management.health.cassandra.enabled:false")
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverReactiveHealthIndicator.class)
+						.doesNotHaveBean("cassandraHealthContributor"));
+	}
+
+	@Test
+	void runWhenSpringDataPresentShouldNotCreateDriverReactiveIndicator() {
+		this.contextRunner.withConfiguration(AutoConfigurations.of(CassandraHealthContributorAutoConfiguration.class))
+				.withBean(CassandraOperations.class, () -> mock(CassandraOperations.class))
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverReactiveHealthIndicator.class)
+						.hasSingleBean(CassandraHealthIndicator.class).hasBean("cassandraHealthContributor"));
+	}
+
+	@Test
+	void runWhenSpringDataAndReactorPresentShouldNotCreateDriverReactiveIndicator() {
+		this.contextRunner
+				.withConfiguration(AutoConfigurations.of(CassandraReactiveHealthContributorAutoConfiguration.class))
+				.withBean(ReactiveCassandraOperations.class, () -> mock(ReactiveCassandraOperations.class))
+				.run((context) -> assertThat(context).doesNotHaveBean(CassandraDriverReactiveHealthIndicator.class)
+						.hasSingleBean(CassandraReactiveHealthIndicator.class).hasBean("cassandraHealthContributor"));
+	}
+
+}

spring-boot-project/spring-boot-actuator/build.gradle

@@ -13,6 +13,7 @@ dependencies {
 	api(project(":spring-boot-project:spring-boot"))
 
 	optional(platform(project(":spring-boot-project:spring-boot-dependencies")))
+	optional("com.datastax.oss:java-driver-core")
 	optional("com.fasterxml.jackson.core:jackson-databind")
 	optional("com.github.ben-manes.caffeine:caffeine")
 	optional("com.hazelcast:hazelcast")

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/cassandra/CassandraDriverHealthIndicator.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2012-2020 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.cassandra;
+
+import com.datastax.oss.driver.api.core.ConsistencyLevel;
+import com.datastax.oss.driver.api.core.CqlSession;
+import com.datastax.oss.driver.api.core.cql.Row;
+import com.datastax.oss.driver.api.core.cql.SimpleStatement;
+
+import org.springframework.boot.actuate.health.AbstractHealthIndicator;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.util.Assert;
+
+/**
+ * Simple implementation of a {@link HealthIndicator} returning status information for
+ * Cassandra data stores.
+ *
+ * This health indicator is automatically used when Spring Data Cassandra is not present,
+ * but the Cassandra driver is.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+public class CassandraDriverHealthIndicator extends AbstractHealthIndicator {
+
+	private static final SimpleStatement SELECT = SimpleStatement
+			.newInstance("SELECT release_version FROM system.local").setConsistencyLevel(ConsistencyLevel.LOCAL_ONE);
+
+	private final CqlSession session;
+
+	/**
+	 * Create a new {@link CassandraDriverHealthIndicator} instance.
+	 * @param session the {@link CqlSession}.
+	 */
+	public CassandraDriverHealthIndicator(CqlSession session) {
+		super("Cassandra health check failed");
+		Assert.notNull(session, "session must not be null");
+		this.session = session;
+	}
+
+	@Override
+	protected void doHealthCheck(Health.Builder builder) throws Exception {
+		Row row = this.session.execute(SELECT).one();
+		builder.up();
+		if (row != null && !row.isNull(0)) {
+			builder.withDetail("version", row.getString(0));
+		}
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/cassandra/CassandraDriverReactiveHealthIndicator.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2020 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.cassandra;
+
+import com.datastax.oss.driver.api.core.ConsistencyLevel;
+import com.datastax.oss.driver.api.core.CqlSession;
+import com.datastax.oss.driver.api.core.cql.SimpleStatement;
+import reactor.core.publisher.Mono;
+
+import org.springframework.boot.actuate.health.AbstractReactiveHealthIndicator;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
+import org.springframework.util.Assert;
+
+/**
+ * Simple implementation of a {@link ReactiveHealthIndicator} returning status information
+ * for Cassandra data stores.
+ *
+ * This health indicator is automatically used when Spring Data Cassandra is not present,
+ * but the Cassandra driver is.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+public class CassandraDriverReactiveHealthIndicator extends AbstractReactiveHealthIndicator {
+
+	private static final SimpleStatement SELECT = SimpleStatement
+			.newInstance("SELECT release_version FROM system.local").setConsistencyLevel(ConsistencyLevel.LOCAL_ONE);
+
+	private final CqlSession session;
+
+	/**
+	 * Create a new {@link CassandraHealthIndicator} instance.
+	 * @param session the {@link CqlSession}.
+	 */
+	public CassandraDriverReactiveHealthIndicator(CqlSession session) {
+		super("Cassandra health check failed");
+		Assert.notNull(session, "session must not be null");
+		this.session = session;
+	}
+
+	@Override
+	protected Mono<Health> doHealthCheck(Health.Builder builder) {
+		return Mono.from(this.session.executeReactive(SELECT))
+				.map((row) -> builder.up().withDetail("version", row.getString(0)).build());
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/cassandra/CassandraDriverHealthIndicatorTests.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2012-2020 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.cassandra;
+
+import com.datastax.oss.driver.api.core.CqlSession;
+import com.datastax.oss.driver.api.core.DriverTimeoutException;
+import com.datastax.oss.driver.api.core.cql.ResultSet;
+import com.datastax.oss.driver.api.core.cql.Row;
+import com.datastax.oss.driver.api.core.cql.SimpleStatement;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.Status;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link CassandraDriverHealthIndicator}.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+class CassandraDriverHealthIndicatorTests {
+
+	@Test
+	void createWhenCqlSessionIsNullShouldThrowException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new CassandraDriverHealthIndicator(null));
+	}
+
+	@Test
+	void healthWithCassandraUp() {
+		CqlSession session = mock(CqlSession.class);
+		ResultSet resultSet = mock(ResultSet.class);
+		Row row = mock(Row.class);
+		given(session.execute(any(SimpleStatement.class))).willReturn(resultSet);
+		given(resultSet.one()).willReturn(row);
+		given(row.isNull(0)).willReturn(false);
+		given(row.getString(0)).willReturn("1.0.0");
+		CassandraDriverHealthIndicator healthIndicator = new CassandraDriverHealthIndicator(session);
+		Health health = healthIndicator.health();
+		assertThat(health.getStatus()).isEqualTo(Status.UP);
+		assertThat(health.getDetails().get("version")).isEqualTo("1.0.0");
+	}
+
+	@Test
+	void healthWithCassandraDown() {
+		CqlSession session = mock(CqlSession.class);
+		given(session.execute(any(SimpleStatement.class))).willThrow(new DriverTimeoutException("Test Exception"));
+		CassandraDriverHealthIndicator healthIndicator = new CassandraDriverHealthIndicator(session);
+		Health health = healthIndicator.health();
+		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
+		assertThat(health.getDetails().get("error"))
+				.isEqualTo(DriverTimeoutException.class.getName() + ": Test Exception");
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/cassandra/CassandraDriverReactiveHealthIndicatorTests.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2012-2020 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.cassandra;
+
+import com.datastax.dse.driver.api.core.cql.reactive.ReactiveResultSet;
+import com.datastax.dse.driver.api.core.cql.reactive.ReactiveRow;
+import com.datastax.oss.driver.api.core.CqlSession;
+import com.datastax.oss.driver.api.core.DriverTimeoutException;
+import com.datastax.oss.driver.api.core.cql.SimpleStatement;
+import org.junit.jupiter.api.Test;
+import org.mockito.stubbing.Answer;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.Status;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.doAnswer;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.mock;
+
+/**
+ * Tests for {@link CassandraDriverReactiveHealthIndicator}.
+ *
+ * @author Alexandre Dutra
+ * @since 2.4.0
+ */
+class CassandraDriverReactiveHealthIndicatorTests {
+
+	@Test
+	void createWhenCqlSessionIsNullShouldThrowException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new CassandraDriverReactiveHealthIndicator(null));
+	}
+
+	@Test
+	void testCassandraIsUp() {
+		CqlSession session = mock(CqlSession.class);
+		ReactiveResultSet results = mock(ReactiveResultSet.class);
+		ReactiveRow row = mock(ReactiveRow.class);
+		given(session.executeReactive(any(SimpleStatement.class))).willReturn(results);
+		doAnswer(mockReactiveResultSetBehavior(row)).when(results).subscribe(any());
+		given(row.getString(0)).willReturn("6.0.0");
+
+		CassandraDriverReactiveHealthIndicator cassandraReactiveHealthIndicator = new CassandraDriverReactiveHealthIndicator(
+				session);
+		Mono<Health> health = cassandraReactiveHealthIndicator.health();
+		StepVerifier.create(health).consumeNextWith((h) -> {
+			assertThat(h.getStatus()).isEqualTo(Status.UP);
+			assertThat(h.getDetails()).containsOnlyKeys("version");
+			assertThat(h.getDetails().get("version")).isEqualTo("6.0.0");
+		}).verifyComplete();
+	}
+
+	@Test
+	void testCassandraIsDown() {
+		CqlSession session = mock(CqlSession.class);
+		given(session.executeReactive(any(SimpleStatement.class)))
+				.willThrow(new DriverTimeoutException("Test Exception"));
+
+		CassandraDriverReactiveHealthIndicator cassandraReactiveHealthIndicator = new CassandraDriverReactiveHealthIndicator(
+				session);
+		Mono<Health> health = cassandraReactiveHealthIndicator.health();
+		StepVerifier.create(health).consumeNextWith((h) -> {
+			assertThat(h.getStatus()).isEqualTo(Status.DOWN);
+			assertThat(h.getDetails()).containsOnlyKeys("error");
+			assertThat(h.getDetails().get("error"))
+					.isEqualTo(DriverTimeoutException.class.getName() + ": Test Exception");
+		}).verifyComplete();
+	}
+
+	private Answer<Void> mockReactiveResultSetBehavior(ReactiveRow row) {
+		return (invocation) -> {
+			Subscriber<ReactiveRow> subscriber = invocation.getArgument(0);
+			Subscription s = new Subscription() {
+				@Override
+				public void request(long n) {
+					subscriber.onNext(row);
+					subscriber.onComplete();
+				}
+
+				@Override
+				public void cancel() {
+				}
+			};
+			subscriber.onSubscribe(s);
+			return null;
+		};
+	}
+
+}