Make credential_path a page attribute instead of page_set attribute.

tools/telemetry/telemetry/core/util_unittest.py

 # Copyright 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 import os
 import shutil
 import tempfile
 import unittest
 
 from telemetry.core import util
 
@@ skipping 44 matching lines @@
       with open(
           os.path.join(self.test_directory, 'test_%03d.json' % i), 'w') as _:
         pass
     next_json_test_file_path = util.GetSequentialFileName(
         os.path.join(self.test_directory, 'test'))
     self.assertEquals(os.path.join(self.test_directory, 'test_003'),
                       next_json_test_file_path)
 
   def tearDown(self):
     shutil.rmtree(self.test_directory)
+
+
+class TestGetAbsPathIfExists(unittest.TestCase):
+  def setUp(self):
+    self.test_directory = tempfile.mkdtemp()
+    self.test_abs_path = tempfile.mkstemp(dir=self.test_directory)[1]
+
+  def testTestGetAbsPathIfExistsWithExistedAbsPathInput(self):
+    self.assertEquals(
+        self.test_abs_path, util.GetAbsPathIfExist(
+            self.test_abs_path, self.test_directory))
+
+  def testTestGetAbsPathIfExistsWithExistedRelativePathInput(self):
+    # Case path = foo and relative path = /tmp/xyz/
+    # (The actual naming maybe different)
+    path = os.path.basename(self.test_abs_path)
+    relative_path = self.test_directory
+    self.assertEquals(
+        self.test_abs_path, util.GetAbsPathIfExist(path, relative_path))
+    # Case path = xyz/foo and relative path = /tmp/
+    # (The actual naming maybe different)
+    path = os.path.join(os.path.basename(self.test_directory),
+                        os.path.basename(self.test_abs_path))
+    relative_path = os.path.join(self.test_directory, os.pardir)
+    self.assertEquals(
+        self.test_abs_path, util.GetAbsPathIfExist(path, relative_path))
+
+  def testTestGetAbsPathIfExistsWithNonExistedPathInput(self):
+    self.assertIsNone(util.GetAbsPathIfExist('foo', self.test_directory))
+    self.assertIsNone(util.GetAbsPathIfExist('foo/bar', self.test_directory))
+
+  def tearDown(self):
+    shutil.rmtree(self.test_directory)