GN: Makes GN output deterministic

tools/gn/pointer_set_unittest.cc

Index: tools/gn/pointer_set_unittest.cc
diff --git a/tools/gn/pointer_set_unittest.cc b/tools/gn/pointer_set_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..299d36ee5738247d4a4f80685c80effc76726b94
--- /dev/null
+++ b/tools/gn/pointer_set_unittest.cc
@@ -0,0 +1,32 @@
+// Copyright (c) 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.

[mithro-old, 2015/12/03 05:20:31]

You could probably use a bunch more tests here.

Do we need checks around null pointers at all?

[Zachary Forman, 2015/12/03 07:27:02]

I've refactored so that we should be as safe as a set is.

Checking for null pointers maybe a good idea - I've added a DCHECK that neither
parameter is a nullptr so that the error message is more sensible than a
segfault.

+
+#include <string>
+#include <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "tools/gn/pointer_set.h"
+
+TEST(PointerSet, Sorted) {
+  std::vector<int> vals{1, 55, 3};
+  PointerSet<int> ps;
+  ps.insert(&vals[0]);
+  ps.insert(&vals[1]);
+  ps.insert(&vals[2]);
+  EXPECT_EQ(1, **ps.begin());

[mithro-old, 2015/12/03 05:20:31]

These EXPECT_EQs are kind of hard to read. 

There are "Container Matchers" avaliable in gmock (which extends gtest). See
https://github.com/google/googletest/blob/master/googlemock/docs/CheatSheet.m...

I'm unsure if they'll make this cleaner.

[Zachary Forman, 2015/12/03 07:27:02]

Acknowledged. Entire set of tests is dead now anyway.

+  EXPECT_EQ(55, **(--ps.end()));
+  EXPECT_EQ(&vals[0], *ps.begin());
+  EXPECT_EQ(&vals[1], *(--ps.end()));
+}
+
+TEST(PointerSet, RangeInsertion) {
+  std::vector<std::string> vals{"abc", "zzz", "cab", "abb", "xyz", "lmn"};
+  std::vector<std::string*> ptrs;
+  for (size_t i = 0; i < vals.size(); i++) {
+    ptrs.push_back(&vals[i]);
+  }
+  PointerSet<std::string> ps(ptrs.begin(), ptrs.end());
+  EXPECT_EQ(6ul, ps.size());
+  EXPECT_EQ(&vals[3], *ps.begin());
+}