Add Jetty SSL keystore in classpath test

Update JettyEmbeddedServletContainerFactoryTests to test loading an
SSL keystore from the classpath. Currently this is a Jetty only feature,
although if https://issues.apache.org/bugzilla/show_bug.cgi?id=56777 is
fixed we could do the same thing with Tomcat.

Closes gh-1943

spring-boot/src/test/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactoryTests.java

@@ -312,6 +312,10 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 
 	@Test
 	public void basicSsl() throws Exception {
+		testBasicSllWithKeystore("src/test/resources/test.jks");
+	}
+
+	protected final void testBasicSllWithKeystore(String keyStore) throws Exception {
 		FileCopyUtils.copy("test",
 				new FileWriter(this.temporaryFolder.newFile("test.txt")));
 
@@ -319,7 +323,7 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 		factory.setDocumentRoot(this.temporaryFolder.getRoot());
 
 		Ssl ssl = new Ssl();
-		ssl.setKeyStore("src/test/resources/test.jks");
+		ssl.setKeyStore(keyStore);
 		ssl.setKeyStorePassword("secret");
 		ssl.setKeyPassword("password");
 		factory.setSsl(ssl);

spring-boot/src/test/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactoryTests.java

@@ -154,4 +154,9 @@ public class JettyEmbeddedServletContainerFactoryTests extends
 		assertThat(getResponse(getLocalUrl("/hello")), equalTo("Hello World"));
 	}
 
+	@Test
+	public void basicSslClasspathKeyStore() throws Exception {
+		testBasicSllWithKeystore("classpath:test.jks");
+	}
+
 }