Add initial prototype for the GN meta-buildsystem.

tools/gn/file_template_unittest.cc

+// Copyright (c) 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.
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "tools/gn/file_template.h"
+
+TEST(FileTemplate, Static) {
+  std::vector<std::string> templates;
+  templates.push_back("something_static");
+  FileTemplate t(templates);
+
+  std::vector<std::string> result;
+  t.ApplyString("", &result);
+  ASSERT_EQ(1u, result.size());
+  EXPECT_EQ("something_static", result[0]);
+
+  t.ApplyString("lalala", &result);
+  ASSERT_EQ(1u, result.size());
+  EXPECT_EQ("something_static", result[0]);
+}
+
+TEST(FileTemplate, Typical) {
+  std::vector<std::string> templates;
+  templates.push_back("foo/{{source_name_part}}.cc");
+  templates.push_back("foo/{{source_name_part}}.h");
+  FileTemplate t(templates);
+
+  std::vector<std::string> result;
+  t.ApplyString("sources/ha.idl", &result);
+  ASSERT_EQ(2u, result.size());
+  EXPECT_EQ("foo/ha.cc", result[0]);
+  EXPECT_EQ("foo/ha.h", result[1]);
+}
+
+TEST(FileTemplate, Weird) {
+  std::vector<std::string> templates;
+  templates.push_back("{{{source}}{{source}}{{");
+  FileTemplate t(templates);
+
+  std::vector<std::string> result;
+  t.ApplyString("foo/lalala.c", &result);
+  ASSERT_EQ(1u, result.size());
+  EXPECT_EQ("{foo/lalala.cfoo/lalala.c{{", result[0]);
+}