Add initial prototype for the GN meta-buildsystem.

tools/gn/source_dir_unittest.cc

Index: tools/gn/source_dir_unittest.cc
diff --git a/tools/gn/source_dir_unittest.cc b/tools/gn/source_dir_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..745513db759923643e3f609873278dc52a7c9a9b
--- /dev/null
+++ b/tools/gn/source_dir_unittest.cc
@@ -0,0 +1,45 @@
+// 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/source_dir.h"
+#include "tools/gn/source_file.h"
+
+TEST(SourceDir, ResolveRelativeFile) {
+  SourceDir base("//base/");
+
+  // Empty input is an error.
+  EXPECT_TRUE(base.ResolveRelativeFile("") == SourceFile());
+
+  // These things are directories, so should be an error.
+  EXPECT_TRUE(base.ResolveRelativeFile("//foo/bar/") == SourceFile());
+  EXPECT_TRUE(base.ResolveRelativeFile("bar/") == SourceFile());
+
+  // Absolute paths should be passed unchanged.
+  EXPECT_TRUE(base.ResolveRelativeFile("//foo") == SourceFile("//foo"));
+  EXPECT_TRUE(base.ResolveRelativeFile("/foo") == SourceFile("/foo"));
+
+  // Basic relative stuff.
+  EXPECT_TRUE(base.ResolveRelativeFile("foo") == SourceFile("//base/foo"));
+  EXPECT_TRUE(base.ResolveRelativeFile("./foo") == SourceFile("//base/foo"));
+  EXPECT_TRUE(base.ResolveRelativeFile("../foo") == SourceFile("//foo"));
+  EXPECT_TRUE(base.ResolveRelativeFile("../../foo") == SourceFile("//foo"));
+}
+
+TEST(SourceDir, ResolveRelativeDir) {
+  SourceDir base("//base/");
+
+  // Empty input is an error.
+  EXPECT_TRUE(base.ResolveRelativeDir("") == SourceDir());
+
+  // Absolute paths should be passed unchanged.
+  EXPECT_TRUE(base.ResolveRelativeDir("//foo") == SourceDir("//foo/"));
+  EXPECT_TRUE(base.ResolveRelativeDir("/foo") == SourceDir("/foo/"));
+
+  // Basic relative stuff.
+  EXPECT_TRUE(base.ResolveRelativeDir("foo") == SourceDir("//base/foo/"));
+  EXPECT_TRUE(base.ResolveRelativeDir("./foo") == SourceDir("//base/foo/"));
+  EXPECT_TRUE(base.ResolveRelativeDir("../foo") == SourceDir("//foo/"));
+  EXPECT_TRUE(base.ResolveRelativeDir("../../foo/") == SourceDir("//foo/"));
+}