Test System Rules with OpenJDK 10

Ensure that System Rules works with JDK 10. JDK 10 removed the method
"getInCheck" from SecurityManager. Therefore the test for the method
"getInCheck" is ignored when testing System Rules with JDK 10 or newer.

.travis.yml

@@ -19,6 +19,7 @@ addons:
     packages:
       - openjdk-6-jdk
 jdk:
+  - openjdk10
   - oraclejdk9
   - oraclejdk8
   - openjdk7

README.md

@@ -54,7 +54,7 @@ System Rules supports [Travis CI](https://travis-ci.org/) (Linux) and
 [AppVeyor](http://www.appveyor.com/) (Windows) for continuous
 integration. Your pull request will be automatically build by both CI
 servers. On Travis CI we build your pull request with OpenJDK 6 and run test
-with different JDKs (Java 6 to 9).
+with different JDKs (Java 6 to 10).
 
 
 ## Release Guide

pom.xml

@@ -9,7 +9,7 @@
 	</parent>
 
 	<artifactId>system-rules</artifactId>
-	<version>1.19.0</version>
+	<version>1.20.0-SNAPSHOT</version>
 	<packaging>jar</packaging>
 
 	<name>System Rules</name>

src/test/java/org/junit/contrib/java/lang/system/internal/NoExitSecurityManagerTest.java

@@ -3,6 +3,7 @@
 import static com.github.stefanbirkner.fishbowl.Fishbowl.exceptionThrownBy;
 import static java.util.Arrays.asList;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assume.assumeTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockingDetails;
 import static org.mockito.Mockito.when;
@@ -209,6 +210,8 @@ public static class with_original_SecurityManager {
 
 		@Test
 		public void getInCheck_is_delegated_to_original_security_manager() {
+			//method "getInCheck" was removed in JDK 10
+			skipOnJavaGreaterThan9();
 			when(originalSecurityManager.getInCheck()).thenReturn(true);
 			assertThat(managerWithOriginal.getInCheck()).isTrue();
 		}
@@ -233,6 +236,13 @@ public void thread_group_of_original_security_manager_is_provided() {
 			when(originalSecurityManager.getThreadGroup()).thenReturn(threadGroup);
 			assertThat(managerWithOriginal.getThreadGroup()).isSameAs(threadGroup);
 		}
+
+		private void skipOnJavaGreaterThan9() {
+			String version = System.getProperty("java.version");
+			assumeTrue(
+				version.startsWith("1.") || version.equals("9")
+			);
+		}
 	}
 
 	public static class without_original_SecurityManager {