Merge pull request #626 from HeartSaVioR/fix-pipeline-throws-npe-without-multi

Fix Pipeline throws NPE using exec without multi (fixes #623)

src/test/java/redis/clients/jedis/tests/PipeliningTest.java

@@ -272,6 +272,26 @@ public class PipeliningTest extends Assert {
 	assertEquals("world", r3.get());
     }
 
+    @Test(expected = JedisDataException.class)
+    public void pipelineExecShoudThrowJedisDataExceptionWhenNotInMulti() {
+	Pipeline pipeline = jedis.pipelined();
+	pipeline.exec();
+    }
+
+    @Test(expected = JedisDataException.class)
+    public void pipelineDiscardShoudThrowJedisDataExceptionWhenNotInMulti() {
+	Pipeline pipeline = jedis.pipelined();
+	pipeline.discard();
+    }
+
+    @Test(expected = JedisDataException.class)
+    public void pipelineMultiShoudThrowJedisDataExceptionWhenAlreadyInMulti() {
+	Pipeline pipeline = jedis.pipelined();
+	pipeline.multi();
+	pipeline.set("foo", "3");
+	pipeline.multi();
+    }
+
     @Test
     public void testDiscardInPipeline() {
 	Pipeline pipeline = jedis.pipelined();