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

See gh-47263

module/spring-boot-batch-jdbc/build.gradle

@@ -47,3 +47,7 @@ dependencies {
 	testRuntimeOnly("com.h2database:h2")
 	testRuntimeOnly("com.zaxxer:HikariCP")
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}

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

@@ -189,9 +189,10 @@ class BatchJdbcAutoConfigurationTests {
 			.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);
 			});
 	}
 
@@ -213,8 +214,11 @@ class BatchJdbcAutoConfigurationTests {
 		this.contextRunner.withUserConfiguration(MultipleJobConfiguration.class, EmbeddedDataSourceConfiguration.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");
 			});
 	}
 
@@ -642,7 +646,7 @@ class BatchJdbcAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override
@@ -679,7 +683,7 @@ class BatchJdbcAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override
@@ -710,7 +714,7 @@ class BatchJdbcAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override
@@ -756,7 +760,7 @@ class BatchJdbcAutoConfigurationTests {
 
 				@Override
 				public Step getStep(String stepName) {
-					return null;
+					return mock(Step.class);
 				}
 
 				@Override