diff --git a/src/test/java/shark/JavaAPISuite.java b/src/test/java/shark/JavaAPISuite.java
index e8d1af43..1f35bb7f 100644
--- a/src/test/java/shark/JavaAPISuite.java
+++ b/src/test/java/shark/JavaAPISuite.java
@@ -71,6 +71,7 @@ public static void oneTimeSetUp() {
     @AfterClass
     public static void oneTimeTearDown() {
         sc.stop();
+        System.clearProperty("spark.driver.port");
     }
 
     @Test
diff --git a/src/test/scala/shark/SQLSuite.scala b/src/test/scala/shark/SQLSuite.scala
index 59406d8f..1cbfe3e4 100644
--- a/src/test/scala/shark/SQLSuite.scala
+++ b/src/test/scala/shark/SQLSuite.scala
@@ -77,6 +77,7 @@ class SQLSuite extends FunSuite with BeforeAndAfterAll {
 
   override def afterAll() {
     sc.stop()
+    System.clearProperty("spark.driver.port")
   }
 
   private def expect(sql: String, expectedResults: Array[String]) {
diff --git a/src/test/scala/shark/SortSuite.scala b/src/test/scala/shark/SortSuite.scala
index 63353d7e..ff9a0801 100644
--- a/src/test/scala/shark/SortSuite.scala
+++ b/src/test/scala/shark/SortSuite.scala
@@ -42,5 +42,6 @@ class SortSuite extends FunSuite {
       assert(output == expected.take(math.min(k, 4)))
     }
     sc.stop()
+    System.clearProperty("spark.driver.port")
   }
 }