[SPARK-11672][ML] flaky spark.ml read/write tests

We set `sqlContext = null` in `afterAll`. However, this doesn't change `SQLContext.activeContext`  and then `SQLContext.getOrCreate` might use the `SparkContext` from previous test suite and hence causes the error. This PR calls `clearActive` in `beforeAll` and `afterAll` to avoid using an old context from other test suites.

cc: yhuai

Author: Xiangrui Meng <meng@databricks.com>

Closes #9677 from mengxr/SPARK-11672.2.

1 files changed, 2 insertions, 2 deletions

diff --git a/mllib/src/test/java/org/apache/spark/ml/util/JavaDefaultReadWriteSuite.java b/mllib/src/test/java/org/apache/spark/ml/util/JavaDefaultReadWriteSuite.java
index 4f7aeac1ec..c39538014b 100644
--- a/mllib/src/test/java/org/apache/spark/ml/util/JavaDefaultReadWriteSuite.java
+++ b/mllib/src/test/java/org/apache/spark/ml/util/JavaDefaultReadWriteSuite.java
@@ -23,7 +23,7 @@ import java.io.IOException;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
-import org.junit.Ignore;
+import org.junit.Test;
 
 import org.apache.spark.api.java.JavaSparkContext;
 import org.apache.spark.sql.SQLContext;
@@ -50,7 +50,7 @@ public class JavaDefaultReadWriteSuite {
     Utils.deleteRecursively(tempDir);
   }
 
-  @Ignore // SPARK-11672
+  @Test
   public void testDefaultReadWrite() throws IOException {
     String uid = "my_params";
     MyParams instance = new MyParams(uid);