Add a Python parser for GN types to gn_helpers.

build/gn_helpers_unittest.py

Index: build/gn_helpers_unittest.py
diff --git a/build/gn_helpers_unittest.py b/build/gn_helpers_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..a493f6778ae24f2097d682ff1e01c8369d3972ac
--- /dev/null
+++ b/build/gn_helpers_unittest.py
@@ -0,0 +1,73 @@
+# 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.
+
+import gn_helpers
+import unittest
+
+class UnitTest(unittest.TestCase):
+  def test_ToGNString(self):
+    self.assertEqual(
+        gn_helpers.ToGNString([1, 'two', [ '"thr$\\', True, False, [] ]]),
+        '[ 1, "two", [ "\\"thr\\$\\\\", true, false, [  ] ] ]')
+
+  def test_UnescapeGNString(self):
+    # Backslash followed by a \, $, or " means the folling character without
+    # the special meaning. Backslash followed by everything else is a literal.
+    self.assertEqual(
+        gn_helpers.UnescapeGNString('\\as\\$\\\\asd\\"'),
+        '\\as$\\asd"')
+
+  def test_FromGNString(self):
+    self.assertEqual(
+        gn_helpers.FromGNString('[1, -20, true, false,["as\\"", []]]'),
+        [ 1, -20, True, False, [ 'as"', [] ] ])
+
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('123 456')
+      parser.Parse()
+
+  def test_ParseNumber(self):
+    parser = gn_helpers.GNValueParser('123')
+    self.assertEqual(parser.ParseNumber(), 123)
+
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('')
+      parser.ParseNumber()
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('a123')
+      parser.ParseNumber()
+
+  def test_ParseString(self):
+    parser = gn_helpers.GNValueParser('"asdf"')
+    self.assertEqual(parser.ParseString(), 'asdf')
+
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('')  # Empty.
+      parser.ParseString()
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('asdf')  # Unquoted.
+      parser.ParseString()
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('"trailing')  # Unterminated.
+      parser.ParseString()
+
+  def test_ParseList(self):
+    parser = gn_helpers.GNValueParser('[1,]')  # Optional end comma OK.
+    self.assertEqual(parser.ParseList(), [ 1 ])
+
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('')  # Empty.
+      parser.ParseList()
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('asdf')  # No [].
+      parser.ParseList()
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('[1, 2')  # Unterminated
+      parser.ParseList()
+    with self.assertRaises(gn_helpers.GNException):
+      parser = gn_helpers.GNValueParser('[1 2]')  # No separating comma.
+      parser.ParseList()
+
+if __name__ == '__main__':
+  unittest.main()