Add regression test

Author: JoshRosen

core/src/test/scala/org/apache/spark/FailureSuite.scala

@@ -141,5 +141,30 @@ class FailureSuite extends SparkFunSuite with LocalSparkContext {
     FailureSuiteState.clear()
   }
 
+  test("managed memory leak error should not mask other failures (SPARK-9266") {
+    val conf = new SparkConf().set("spark.unsafe.exceptionOnMemoryLeak", "true")
+    sc = new SparkContext("local[1,1]", "test", conf)
+
+    // If a task leaks memory but fails due to some other cause, then make sure that the original
+    // cause is preserved
+    val thrownDueToTaskFailure = intercept[SparkException] {
+      sc.parallelize(Seq(0)).mapPartitions { iter =>
+        TaskContext.get().taskMemoryManager().allocate(128)
+        throw new Exception("intentional task failure")
+        iter
+      }.count()
+    }
+    assert(thrownDueToTaskFailure.getMessage.contains("intentional task failure"))
+
+    // If the task succeeded but memory was leaked, then the task should fail due to that leak
+    val thrownDueToMemoryLeak = intercept[SparkException] {
+      sc.parallelize(Seq(0)).mapPartitions { iter =>
+        TaskContext.get().taskMemoryManager().allocate(128)
+        iter
+      }.count()
+    }
+    assert(thrownDueToMemoryLeak.getMessage.contains("memory leak"))
+  }
+
   // TODO: Need to add tests with shuffle fetch failures.
 }