Use real IDL types in unit test stubs.

third_party/WebKit/Source/bindings/scripts/idl_definitions_test.py

Index: third_party/WebKit/Source/bindings/scripts/idl_definitions_test.py
diff --git a/third_party/WebKit/Source/bindings/scripts/idl_definitions_test.py b/third_party/WebKit/Source/bindings/scripts/idl_definitions_test.py
new file mode 100644
index 0000000000000000000000000000000000000000..78dd73207445859d0dd1e71365bb92235f6e3a30
--- /dev/null
+++ b/third_party/WebKit/Source/bindings/scripts/idl_definitions_test.py
@@ -0,0 +1,21 @@
+# Copyright 2016 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.
+
+# pylint: disable=import-error,print-statement,relative-import
+
+"""Unit tests for idl_definitions.py."""
+
+import unittest
+
+from idl_definitions import IdlAttribute
+
+
+class IdlAttributeTest(unittest.TestCase):
+
+    def test_no_params(self):
+        try:
+            IdlAttribute()
+        except Exception as exception:  # pylint: disable=broad-except
+            self.fail('Creating an IdlAttribute with no parameters raised'
+                      'an exception: {}.'.format(exception))