[Android] Refactor md5_check + add tests

build/android/gyp/util/md5_check_test.py

+# Copyright 2013 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 tempfile
+import unittest
+
+import md5_check
+
+
+class TestMd5Check(unittest.TestCase):
+  def testCallAndRecordIfStale(self):
+    input_strings = ['string1', 'string2']
+    input_file1 = tempfile.NamedTemporaryFile()
+    input_file2 = tempfile.NamedTemporaryFile()
+    file1_contents = 'input file 1'
+    file2_contents = 'input file 2'
+    input_file1.write(file1_contents)
+    input_file1.flush()
+    input_file2.write(file2_contents)
+    input_file2.flush()
+    input_files = [input_file1.name, input_file2.name]
+
+    record_path = tempfile.NamedTemporaryFile(suffix='.stamp')
+
+    def CheckCallAndRecord(should_call, message):
+      self.called = False
+      def MarkCalled():
+        self.called = True
+      md5_check.CallAndRecordIfStale(
+          MarkCalled,
+          record_path=record_path.name,
+          input_paths=input_files,
+          input_strings=input_strings)
+      self.failUnlessEqual(should_call, self.called, message)
+
+    CheckCallAndRecord(True, 'should call when record doesn\'t exist')
+    CheckCallAndRecord(False, 'should not call when nothing changed')
+
+    input_file1.write('some more input')
+    input_file1.flush()
+    CheckCallAndRecord(True, 'changed input file should trigger call')
+
+    input_files = input_files[::-1]
+    CheckCallAndRecord(False, 'reordering of inputs shouldn\'t trigger call')
+
+    input_files = input_files[:1]
+    CheckCallAndRecord(True, 'removing file should trigger call')
+
+    input_files.append(input_file2.name)
+    CheckCallAndRecord(True, 'added input file should trigger call')
+
+    input_strings[0] = input_strings[0] + ' a bit longer'
+    CheckCallAndRecord(True, 'changed input string should trigger call')
+
+    input_strings = input_strings[::-1]
+    CheckCallAndRecord(True, 'reordering of string inputs should trigger call')
+
+    input_strings = input_strings[:1]
+    CheckCallAndRecord(True, 'removing a string should trigger call')
+
+    input_strings.append('a brand new string')
+    CheckCallAndRecord(True, 'added input string should trigger call')
+
+
+if __name__ == '__main__':
+  unittest.main()