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

See gh-47263

module/spring-boot-tomcat/build.gradle

@@ -83,3 +83,7 @@ sourceSets {
 test {
 	jvmArgs += "--add-opens=java.base/java.net=ALL-UNNAMED"
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/TomcatEmbeddedWebappClassLoaderTests.java

@@ -45,6 +45,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 class TomcatEmbeddedWebappClassLoaderTests {
 
 	@TempDir
+	@SuppressWarnings("NullAway.Init")
 	File tempDir;
 
 	@Test

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/TomcatServerPropertiesTests.java

@@ -232,7 +232,10 @@ class TomcatServerPropertiesTests {
 	void tomcatMaxKeepAliveRequestsDefault() throws Exception {
 		AbstractEndpoint<?, ?> endpoint = (AbstractEndpoint<?, ?>) ReflectionTestUtils.getField(getDefaultProtocol(),
 				"endpoint");
-		int defaultMaxKeepAliveRequests = (int) ReflectionTestUtils.getField(endpoint, "maxKeepAliveRequests");
+		assertThat(endpoint).isNotNull();
+		Object value = ReflectionTestUtils.getField(endpoint, "maxKeepAliveRequests");
+		assertThat(value).isNotNull();
+		int defaultMaxKeepAliveRequests = (int) value;
 		assertThat(this.properties.getMaxKeepAliveRequests()).isEqualTo(defaultMaxKeepAliveRequests);
 	}
 

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizerTests.java

@@ -30,6 +30,7 @@ import org.apache.coyote.AbstractProtocol;
 import org.apache.coyote.ajp.AbstractAjpProtocol;
 import org.apache.coyote.http11.AbstractHttp11Protocol;
 import org.apache.coyote.http2.Http2Protocol;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -655,7 +656,7 @@ class TomcatWebServerFactoryCustomizerTests {
 		customizeAndRunServer(null);
 	}
 
-	private void customizeAndRunServer(Consumer<TomcatWebServer> consumer) {
+	private void customizeAndRunServer(@Nullable Consumer<TomcatWebServer> consumer) {
 		TomcatWebServer server = customizeAndGetServer();
 		server.start();
 		try {

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/metrics/TomcatMetricsAutoConfigurationTests.java

@@ -111,13 +111,14 @@ class TomcatMetricsAutoConfigurationTests {
 	}
 
 	private ApplicationStartedEvent createApplicationStartedEvent(ConfigurableApplicationContext context) {
-		return new ApplicationStartedEvent(new SpringApplication(), null, context, null);
+		return new ApplicationStartedEvent(new SpringApplication(), new String[0], context, null);
 	}
 
 	private void resetTomcatState() {
 		ReflectionTestUtils.setField(Registry.class, "registry", null);
 		AtomicInteger containerCounter = (AtomicInteger) ReflectionTestUtils.getField(TomcatWebServer.class,
 				"containerCounter");
+		assertThat(containerCounter).isNotNull();
 		containerCounter.set(-1);
 	}
 

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/reactive/TomcatReactiveWebServerAutoConfigurationTests.java

@@ -128,6 +128,7 @@ class TomcatReactiveWebServerAutoConfigurationTests extends AbstractReactiveWebS
 		this.serverRunner.run((context) -> {
 			WebServer webServer = ((ReactiveWebServerApplicationContext) context.getSourceApplicationContext())
 				.getWebServer();
+			assertThat(webServer).isNotNull();
 			ServletContext servletContext = findContext(((TomcatWebServer) webServer).getTomcat()).getServletContext();
 			Object serverContainer = servletContext.getAttribute("jakarta.websocket.server.ServerContainer");
 			assertThat(serverContainer).isInstanceOf(ServerContainer.class);

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/reactive/TomcatReactiveWebServerFactoryTests.java

@@ -132,6 +132,7 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void setNullConnectorCustomizersShouldThrowException() {
 		TomcatReactiveWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.setConnectorCustomizers(null))
@@ -139,6 +140,7 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullAddConnectorCustomizersShouldThrowException() {
 		TomcatReactiveWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException()
@@ -147,6 +149,7 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void setNullProtocolHandlerCustomizersShouldThrowException() {
 		TomcatReactiveWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.setProtocolHandlerCustomizers(null))
@@ -154,6 +157,7 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullProtocolHandlerCustomizersShouldThrowException() {
 		TomcatReactiveWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException()
@@ -205,6 +209,7 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullAdditionalConnectorsThrows() {
 		TomcatReactiveWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.addAdditionalConnectors((Connector[]) null))
@@ -277,8 +282,9 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 
 			@Override
 			protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {
-				webServerReference.set(new TomcatWebServer(tomcat));
-				return webServerReference.get();
+				TomcatWebServer server = new TomcatWebServer(tomcat);
+				webServerReference.set(server);
+				return server;
 			}
 
 		}.getWebServer(new EchoHandler());

module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/servlet/TomcatServletWebServerFactoryTests.java

@@ -75,6 +75,7 @@ import org.apache.tomcat.JarScanType;
 import org.apache.tomcat.util.scan.StandardJarScanFilter;
 import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
 import org.awaitility.Awaitility;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.InOrder;
@@ -245,8 +246,10 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 			.setProcessorCache(250);
 		factory.addProtocolHandlerCustomizers(customizer);
 		Tomcat tomcat = getTomcat(factory);
-		Connector connector = TomcatAccess.getServiceConnectors((TomcatWebServer) this.webServer)
-			.get(tomcat.getService())[0];
+		Connector[] connectors = TomcatAccess.getServiceConnectors((TomcatWebServer) this.webServer)
+			.get(tomcat.getService());
+		assertThat(connectors).isNotNull();
+		Connector connector = connectors[0];
 		AbstractHttp11Protocol<?> protocolHandler = (AbstractHttp11Protocol<?>) connector.getProtocolHandler();
 		assertThat(protocolHandler.getProcessorCache()).isEqualTo(250);
 	}
@@ -275,6 +278,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullAdditionalConnectorThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.addAdditionalConnectors((Connector[]) null))
@@ -312,6 +316,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void setNullTomcatContextCustomizersThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.setContextCustomizers(null))
@@ -319,6 +324,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullContextCustomizersThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException()
@@ -327,6 +333,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void setNullTomcatConnectorCustomizersThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.setConnectorCustomizers(null))
@@ -334,6 +341,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullConnectorCustomizersThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException()
@@ -342,6 +350,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void setNullTomcatProtocolHandlerCustomizersThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException().isThrownBy(() -> factory.setProtocolHandlerCustomizers(null))
@@ -349,6 +358,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Test
+	@SuppressWarnings("NullAway") // Test null check
 	void addNullTomcatProtocolHandlerCustomizersThrows() {
 		TomcatServletWebServerFactory factory = getFactory();
 		assertThatIllegalArgumentException()
@@ -361,8 +371,10 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 		TomcatServletWebServerFactory factory = getFactory();
 		factory.setUriEncoding(StandardCharsets.US_ASCII);
 		Tomcat tomcat = getTomcat(factory);
-		Connector connector = TomcatAccess.getServiceConnectors((TomcatWebServer) this.webServer)
-			.get(tomcat.getService())[0];
+		Connector[] connectors = TomcatAccess.getServiceConnectors((TomcatWebServer) this.webServer)
+			.get(tomcat.getService());
+		assertThat(connectors).isNotNull();
+		Connector connector = connectors[0];
 		assertThat(connector.getURIEncoding()).isEqualTo("US-ASCII");
 	}
 
@@ -370,8 +382,10 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	void defaultUriEncoding() {
 		TomcatServletWebServerFactory factory = getFactory();
 		Tomcat tomcat = getTomcat(factory);
-		Connector connector = TomcatAccess.getServiceConnectors((TomcatWebServer) this.webServer)
-			.get(tomcat.getService())[0];
+		Connector[] connectors = TomcatAccess.getServiceConnectors((TomcatWebServer) this.webServer)
+			.get(tomcat.getService());
+		assertThat(connectors).isNotNull();
+		Connector connector = connectors[0];
 		assertThat(connector.getURIEncoding()).isEqualTo("UTF-8");
 	}
 
@@ -553,7 +567,9 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 		});
 		this.webServer = factory.getWebServer();
 		this.webServer.start();
-		File temp = (File) servletContextReference.get().getAttribute(ServletContext.TEMPDIR);
+		ServletContext servletContext = servletContextReference.get();
+		assertThat(servletContext).isNotNull();
+		File temp = (File) servletContext.getAttribute(ServletContext.TEMPDIR);
 		FileSystemUtils.deleteRecursively(temp);
 		RestTemplate restTemplate = new RestTemplate();
 		HttpHeaders headers = new HttpHeaders();
@@ -697,7 +713,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Override
-	protected JspServlet getJspServlet() throws ServletException {
+	protected @Nullable JspServlet getJspServlet() throws ServletException {
 		Tomcat tomcat = ((TomcatWebServer) this.webServer).getTomcat();
 		Container container = tomcat.getHost().findChildren()[0];
 		StandardWrapper standardWrapper = (StandardWrapper) container.findChild("jsp");
@@ -719,7 +735,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Override
-	protected Charset getCharset(Locale locale) {
+	protected @Nullable Charset getCharset(Locale locale) {
 		Context context = (Context) ((TomcatWebServer) this.webServer).getTomcat().getHost().findChildren()[0];
 		CharsetMapper mapper = ((TomcatEmbeddedContext) context).getCharsetMapper();
 		String charsetName = mapper.getCharset(locale);
@@ -756,7 +772,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 
 	private static final class RememberingHostnameVerifier implements HostnameVerifier {
 
-		private volatile String lastPrincipal;
+		private volatile @Nullable String lastPrincipal;
 
 		@Override
 		public boolean verify(String hostname, SSLSession session) {
@@ -769,7 +785,7 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 			return true;
 		}
 
-		String getLastPrincipal() {
+		@Nullable String getLastPrincipal() {
 			return this.lastPrincipal;
 		}
 

module/spring-boot-web-server/src/testFixtures/java/org/springframework/boot/web/server/servlet/AbstractServletWebServerFactoryTests.java

@@ -713,21 +713,23 @@ public abstract class AbstractServletWebServerFactoryTests {
 		assertThat(response.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND);
 	}
 
-	protected Ssl getSsl(ClientAuth clientAuth, String keyPassword, String keyStore) {
+	protected Ssl getSsl(@Nullable ClientAuth clientAuth, @Nullable String keyPassword, @Nullable String keyStore) {
 		return getSsl(clientAuth, keyPassword, keyStore, null, null, null);
 	}
 
-	protected Ssl getSsl(ClientAuth clientAuth, String keyPassword, String keyAlias, String keyStore) {
+	protected Ssl getSsl(@Nullable ClientAuth clientAuth, @Nullable String keyPassword, @Nullable String keyAlias,
+			@Nullable String keyStore) {
 		return getSsl(clientAuth, keyPassword, keyAlias, keyStore, null, null, null);
 	}
 
-	protected Ssl getSsl(ClientAuth clientAuth, String keyPassword, String keyStore, String trustStore,
-			String[] supportedProtocols, String[] ciphers) {
+	protected Ssl getSsl(@Nullable ClientAuth clientAuth, @Nullable String keyPassword, @Nullable String keyStore,
+			@Nullable String trustStore, String @Nullable [] supportedProtocols, String @Nullable [] ciphers) {
 		return getSsl(clientAuth, keyPassword, null, keyStore, trustStore, supportedProtocols, ciphers);
 	}
 
-	private Ssl getSsl(ClientAuth clientAuth, String keyPassword, String keyAlias, String keyStore, String trustStore,
-			String[] supportedProtocols, String[] ciphers) {
+	private Ssl getSsl(@Nullable ClientAuth clientAuth, @Nullable String keyPassword, @Nullable String keyAlias,
+			@Nullable String keyStore, @Nullable String trustStore, String @Nullable [] supportedProtocols,
+			String @Nullable [] ciphers) {
 		Ssl ssl = new Ssl();
 		ssl.setClientAuth(clientAuth);
 		if (keyPassword != null) {