Skips Cassandra and Elasticsearch tests on Windows

Neither Cassandra nor Elasticsearch starts reliably on Windows. This
commit adds a custom class rule to the associated sample application
tests to skip them on Windows. A class rule is used rather than a
Unit assumption as we want to avoid starting Elasticsearch (done by
the application context) and Cassandra (done by a test execution
listener) and an assumption would be too late.

spring-boot-samples/spring-boot-sample-data-cassandra/src/test/java/sample/data/cassandra/SampleCassandraApplicationTests.java

@@ -16,11 +16,16 @@
 
 package sample.data.cassandra;
 
+import java.io.File;
+
 import org.cassandraunit.spring.CassandraDataSet;
 import org.cassandraunit.spring.EmbeddedCassandra;
 import org.junit.ClassRule;
 import org.junit.Test;
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
 import org.junit.runner.RunWith;
+import org.junit.runners.model.Statement;
 
 import org.springframework.boot.test.IntegrationTest;
 import org.springframework.boot.test.IntegrationTestPropertiesListener;
@@ -48,6 +53,9 @@ public class SampleCassandraApplicationTests {
 	@ClassRule
 	public static OutputCapture outputCapture = new OutputCapture();
 
+	@ClassRule
+	public static SkipOnWindows skipOnWindows = new SkipOnWindows();
+
 	@Test
 	public void testDefaultSettings() throws Exception {
 		String output = SampleCassandraApplicationTests.outputCapture.toString();
@@ -55,4 +63,26 @@ public class SampleCassandraApplicationTests {
 				output.contains("firstName='Alice', lastName='Smith'"));
 	}
 
+	static class SkipOnWindows implements TestRule {
+
+		@Override
+		public Statement apply(final Statement base, Description description) {
+			return new Statement() {
+
+				@Override
+				public void evaluate() throws Throwable {
+					if (!runningOnWindows()) {
+						base.evaluate();
+					}
+				}
+
+				private boolean runningOnWindows() {
+					return File.separatorChar == '\\';
+				}
+
+			};
+		}
+
+	}
+
 }