HADOOP-13166. Add getFileStatus("/") test to AbstractContractGetFileStatusTest. Contributed by Steve Loughran

(cherry picked from commit 2bf9a15e8a)

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/contract/AbstractContractGetFileStatusTest.java

@@ -72,6 +72,12 @@ public abstract class AbstractContractGetFileStatusTest extends
     }
   }
 
+  @Test
+  public void testGetFileStatusRoot() throws Throwable {
+    ContractTestUtils.assertIsDirectory(
+        getFileSystem().getFileStatus(new Path("/")));
+  }
+
   @Test
   public void testListStatusEmptyDirectory() throws IOException {
     describe("List status on an empty directory");