Allow GN configs to have sub-configs.

tools/gn/config_unittest.cc

+// Copyright 2015 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/config.h"
+#include "tools/gn/test_with_scope.h"
+
+// Tests that the "resolved" values are the same as "own" values when there
+// are no subconfigs.
+TEST(Config, ResolvedNoSub) {
+  TestWithScope setup;
+  Err err;
+
+  Config config(setup.settings(), Label(SourceDir("//foo/"), "bar"));
+  config.own_values().defines().push_back("FOO");
+  ASSERT_TRUE(config.OnResolved(&err));
+
+  // The resolved values should be the same as the value we put in to
+  // own_values().
+  ASSERT_EQ(1u, config.resolved_values().defines().size());
+  EXPECT_EQ("FOO", config.resolved_values().defines()[0]);
+
+  // As an optimization, the string should actually refer to the original. This
+  // isn't required to pass for semantic correctness, though.
+  EXPECT_TRUE(&config.own_values() == &config.resolved_values());
+}
+
+// Tests that subconfigs are resolved in the correct order.
+TEST(Config, ResolvedSub) {
+  TestWithScope setup;
+  Err err;
+
+  Config sub1(setup.settings(), Label(SourceDir("//foo/"), "1"));
+  sub1.own_values().defines().push_back("ONE");
+  ASSERT_TRUE(sub1.OnResolved(&err));
+
+  Config sub2(setup.settings(), Label(SourceDir("//foo/"), "2"));
+  sub2.own_values().defines().push_back("TWO");
+  ASSERT_TRUE(sub2.OnResolved(&err));
+
+  Config config(setup.settings(), Label(SourceDir("//foo/"), "bar"));
+  config.own_values().defines().push_back("FOO");
+  config.configs().push_back(LabelConfigPair(&sub1));
+  config.configs().push_back(LabelConfigPair(&sub2));
+  ASSERT_TRUE(config.OnResolved(&err));
+
+  // The resolved values should be the same as the value we put in to
+  // own_values().
+  ASSERT_EQ(3u, config.resolved_values().defines().size());
+  EXPECT_EQ("FOO", config.resolved_values().defines()[0]);
+  EXPECT_EQ("ONE", config.resolved_values().defines()[1]);
+  EXPECT_EQ("TWO", config.resolved_values().defines()[2]);
+
+  // The "own" values should be unchanged.
+  ASSERT_EQ(1u, config.own_values().defines().size());
+  EXPECT_EQ("FOO", config.own_values().defines()[0]);
+}
+
+// Tests that subconfigs of subconfigs are resolved properly.
+TEST(Config, SubSub) {
+  TestWithScope setup;
+  Err err;
+
+  // Set up first -> middle -> last configs.
+  Config last(setup.settings(), Label(SourceDir("//foo/"), "last"));
+  last.own_values().defines().push_back("LAST");
+  ASSERT_TRUE(last.OnResolved(&err));
+
+  Config middle(setup.settings(), Label(SourceDir("//foo/"), "middle"));
+  middle.own_values().defines().push_back("MIDDLE");
+  middle.configs().push_back(LabelConfigPair(&last));
+  ASSERT_TRUE(middle.OnResolved(&err));
+
+  Config first(setup.settings(), Label(SourceDir("//foo/"), "first"));
+  first.own_values().defines().push_back("FIRST");
+  first.configs().push_back(LabelConfigPair(&middle));
+  ASSERT_TRUE(first.OnResolved(&err));
+
+  // Check final resolved defines on "first".
+  ASSERT_EQ(3u, first.resolved_values().defines().size());
+  EXPECT_EQ("FIRST", first.resolved_values().defines()[0]);
+  EXPECT_EQ("MIDDLE", first.resolved_values().defines()[1]);
+  EXPECT_EQ("LAST", first.resolved_values().defines()[2]);
+}