Add nullability annotations to tests in module/spring-boot-batch

See gh-47263

module/spring-boot-batch/build.gradle

@@ -40,3 +40,7 @@ dependencies {
 	testRuntimeOnly("com.fasterxml.jackson.core:jackson-databind")
 	testRuntimeOnly("com.fasterxml.jackson.datatype:jackson-datatype-jsr310")
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}

module/spring-boot-batch/src/test/java/org/springframework/boot/batch/autoconfigure/BatchJobLauncherAutoConfigurationTests.java

@@ -39,6 +39,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
 
 /**
  * Tests for {@link BatchJobLauncherAutoConfiguration}.
@@ -78,9 +79,10 @@ class BatchJobLauncherAutoConfigurationTests {
 			.run((context) -> {
 				assertThat(context).hasSingleBean(JobOperator.class);
 				context.getBean(JobLauncherApplicationRunner.class).run();
-				assertThat(context.getBean(JobRepository.class)
-					.getLastJobExecution("discreteRegisteredJob", new JobParameters())
-					.getStatus()).isEqualTo(BatchStatus.COMPLETED);
+				JobExecution lastJobExecution = context.getBean(JobRepository.class)
+					.getLastJobExecution("discreteRegisteredJob", new JobParameters());
+				assertThat(lastJobExecution).isNotNull();
+				assertThat(lastJobExecution.getStatus()).isEqualTo(BatchStatus.COMPLETED);
 			});
 	}
 
@@ -100,8 +102,11 @@ class BatchJobLauncherAutoConfigurationTests {
 	void testMultipleJobsAndNoJobName() {
 		this.contextRunner.withUserConfiguration(MultipleJobConfiguration.class).run((context) -> {
 			assertThat(context).hasFailed();
-			assertThat(context.getStartupFailure().getCause().getMessage())
-				.contains("Job name must be specified in case of multiple jobs");
+			Throwable startupFailure = context.getStartupFailure();
+			assertThat(startupFailure).isNotNull();
+			Throwable cause = startupFailure.getCause();
+			assertThat(cause).isNotNull();
+			assertThat(cause.getMessage()).contains("Job name must be specified in case of multiple jobs");
 		});
 	}
 
@@ -146,7 +151,7 @@ class BatchJobLauncherAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override
@@ -183,7 +188,7 @@ class BatchJobLauncherAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override
@@ -214,7 +219,7 @@ class BatchJobLauncherAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override
@@ -260,7 +265,7 @@ class BatchJobLauncherAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override