Android: some minor improvements to jni_generator_tests.py

base/android/jni_generator/jni_generator_tests.py

 #!/usr/bin/env python
 # Copyright (c) 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.
 
 """Tests for jni_generator.py.
 
 This test suite contains various tests for the JNI generator.
 It exercises the low-level parser all the way up to the
 code generator and ensures the output matches a golden
 file.
 """
 
 import difflib
 import inspect
 import os
 import sys
 import unittest
 import jni_generator
 from jni_generator import CalledByNative, JniParams, NativeMethod, Param
 
 
 SCRIPT_NAME = 'base/android/jni_generator/jni_generator.py'
 
+# Set this environment variable in order to regenerate the golden text
+# files.
+REBASELINE_ENV = 'REBASELINE'
 
 class TestOptions(object):
   """The mock options object which is passed to the jni_generator.py script."""
 
   def __init__(self):
     self.namespace = None
     self.script_name = SCRIPT_NAME
     self.ptr_type = 'int'
 
 
@@ skipping 41 matching lines @@
       self.fail('Golden text mismatch.')
 
   def _ReadGoldenFile(self, golden_file):
     if not os.path.exists(golden_file):
       return None
     with file(golden_file, 'r') as f:
       return f.read()
 
   def assertGoldenTextEquals(self, generated_text):
     script_dir = os.path.dirname(sys.argv[0])
+    # This is the caller test method.
     caller = inspect.stack()[1][3]
+    self.assertTrue(caller.startswith('test'),
+                    'assertGoldenTextEquals can only be called from a '
+                    'test* method, not %s' % caller)
     golden_file = os.path.join(script_dir, caller + '.golden')
     golden_text = self._ReadGoldenFile(golden_file)
-    if os.environ.get('REBASELINE'):
+    if os.environ.get(REBASELINE_ENV):
       if golden_text != generated_text:
         with file(golden_file, 'w') as f:
           f.write(generated_text)
       return
     self.assertTextEquals(golden_text, generated_text)
 
+  def testInspectCaller(self):
+    def willRaise():
+      # This function can only be called from a test* method.
+      self.assertGoldenTextEquals('')
+    self.assertRaises(AssertionError, willRaise)
+
   def testNatives(self):
     test_data = """"
     interface OnFrameAvailableListener {}
     private native int nativeInit();
     private native void nativeDestroy(int nativeChromeBrowserProvider);
     private native long nativeAddBookmark(
             int nativeChromeBrowserProvider,
             String url, String title, boolean isFolder, long parentId);
     private static native String nativeGetDomainAndRegistry(String url);
     private static native void nativeCreateHistoricalTabFromState(
@@ skipping 804 matching lines @@
                      ptr_type=test_options.ptr_type),
     ]
     self.assertListEquals(golden_natives, natives)
     h = jni_generator.InlHeaderFileGenerator('', 'org/chromium/TestJni',
                                              natives, [], test_options)
     self.assertGoldenTextEquals(h.GetContent())
 
 
 if __name__ == '__main__':
   unittest.main()