Add nullability annotations to tests in smoke-test/spring-boot-smoke-test-web-groovy-templates

See gh-47263

smoke-test/spring-boot-smoke-test-web-groovy-templates/build.gradle

@@ -29,3 +29,7 @@ dependencies {
 	testImplementation(project(":starter:spring-boot-starter-test"))
 	testImplementation(project(":starter:spring-boot-starter-webmvc-test"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}

smoke-test/spring-boot-smoke-test-web-groovy-templates/src/test/java/smoketest/groovytemplates/SampleGroovyTemplateApplicationTests.java

@@ -62,6 +62,7 @@ class SampleGroovyTemplateApplicationTests {
 		map.set("text", "FOO text");
 		map.set("summary", "FOO");
 		URI location = this.restTemplate.postForLocation("/", map);
+		assertThat(location).isNotNull();
 		assertThat(location.toString()).contains("localhost:" + this.port);
 	}