Add TestDfsPathCapabilities.

hadoop-hdfs-project/hadoop-hdfs-client/src/test/java/org/apache/hadoop/hdfs/client/TestDfsPathCapabilities.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.client;
+
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.apache.hadoop.fs.CommonPathCapabilities.FS_SYMLINKS;
+
+public class TestDfsPathCapabilities {
+  /**
+   * Test if {@link DistributedFileSystem#hasPathCapability(Path, String)}
+   * returns correct result for FS_SYMLINKS.
+   */
+  @Test
+  public void testFS_SYMLINKS() throws Exception {
+    final HdfsConfiguration conf = new HdfsConfiguration();
+    conf.set(FileSystem.FS_DEFAULT_NAME_KEY, "hdfs://localhost/");
+    final FileSystem fs = FileSystem.get(conf);
+    Assert.assertTrue(fs instanceof DistributedFileSystem);
+    final DistributedFileSystem dfs = (DistributedFileSystem) fs;
+    final Path path = new Path("/");
+    Assert.assertTrue(dfs.supportsSymlinks());
+
+    // Symlinks disabled
+    Assert.assertFalse(FileSystem.areSymlinksEnabled());
+    Assert.assertFalse(dfs.hasPathCapability(path, FS_SYMLINKS));
+
+    // Symlinks enabled
+    FileSystem.enableSymlinks();
+    Assert.assertTrue(FileSystem.areSymlinksEnabled());
+    Assert.assertTrue(dfs.hasPathCapability(path, FS_SYMLINKS));
+  }
+}