diff --git a/module/spring-boot-micrometer-observation/build.gradle b/module/spring-boot-micrometer-observation/build.gradle
index a0b72d4ea65..1c49cb12238 100644
--- a/module/spring-boot-micrometer-observation/build.gradle
+++ b/module/spring-boot-micrometer-observation/build.gradle
@@ -36,3 +36,7 @@ dependencies {
 
 	testRuntimeOnly("ch.qos.logback:logback-classic")
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationAutoConfigurationTests.java b/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationAutoConfigurationTests.java
index 60342f4e381..37d67abccd0 100644
--- a/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationAutoConfigurationTests.java
+++ b/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationAutoConfigurationTests.java
@@ -115,7 +115,9 @@ class ObservationAutoConfigurationTests {
 			Observation observation = Observation.start("filtered", observationRegistry);
 			observation.stop();
 			observation.getContext().getLowCardinalityKeyValues().forEach((kv) -> System.out.println(kv.getKey()));
-			assertThat(observation.getContext().getLowCardinalityKeyValue("filter").getValue()).isEqualTo("one");
+			KeyValue filter = observation.getContext().getLowCardinalityKeyValue("filter");
+			assertThat(filter).isNotNull();
+			assertThat(filter.getValue()).isEqualTo("one");
 		});
 	}
 
@@ -131,7 +133,9 @@ class ObservationAutoConfigurationTests {
 			ObservationRegistry observationRegistry = context.getBean(ObservationRegistry.class);
 			Observation observation = Observation.start("keyvalues", observationRegistry);
 			observation.stop();
-			assertThat(observation.getContext().getLowCardinalityKeyValue("a").getValue()).isEqualTo("alpha");
+			KeyValue a = observation.getContext().getLowCardinalityKeyValue("a");
+			assertThat(a).isNotNull();
+			assertThat(a.getValue()).isEqualTo("alpha");
 		});
 	}
 
diff --git a/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationHandlerGroupsTests.java b/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationHandlerGroupsTests.java
index a393082015b..4c881c888b2 100644
--- a/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationHandlerGroupsTests.java
+++ b/module/spring-boot-micrometer-observation/src/test/java/org/springframework/boot/micrometer/observation/autoconfigure/ObservationHandlerGroupsTests.java
@@ -86,8 +86,12 @@ class ObservationHandlerGroupsTests {
 	@SuppressWarnings("unchecked")
 	private static List<ObservationHandler<?>> getObservationHandlers(ObservationConfig config) {
 		Method method = ReflectionUtils.findMethod(ObservationConfig.class, "getObservationHandlers");
+		assertThat(method).isNotNull();
 		ReflectionUtils.makeAccessible(method);
-		return (List<ObservationHandler<?>>) ReflectionUtils.invokeMethod(method, config);
+		List<ObservationHandler<?>> observationHandlers = (List<ObservationHandler<?>>) ReflectionUtils
+			.invokeMethod(method, config);
+		assertThat(observationHandlers).isNotNull();
+		return observationHandlers;
 	}
 
 	private static class NamedObservationHandler implements ObservationHandler<Observation.Context> {