headless: Add error reporter utility

headless/public/util/error_reporter_unittest.cc

Index: headless/public/util/error_reporter_unittest.cc
diff --git a/headless/public/util/error_reporter_unittest.cc b/headless/public/util/error_reporter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f23ced9ef2993bfd2a858f72ed2be270ae21bf7a
--- /dev/null
+++ b/headless/public/util/error_reporter_unittest.cc
@@ -0,0 +1,52 @@
+// 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.
+
+#include "headless/public/util/error_reporter.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace headless {
+
+TEST(ErrorReporterTest, NoErrors) {
+  ErrorReporter reporter;
+  EXPECT_FALSE(reporter.HasErrors());
+  EXPECT_TRUE(reporter.errors().empty());
+}
+
+TEST(ErrorReporterTest, TopLevelErrors) {
+  ErrorReporter reporter;
+  reporter.AddError("instructions unclear");
+  reporter.AddError("head stuck in std::unordered_map");
+  EXPECT_TRUE(reporter.HasErrors());
+  EXPECT_EQ(2u, reporter.errors().size());
+  EXPECT_EQ("instructions unclear", reporter.errors()[0]);
+  EXPECT_EQ("head stuck in std::unordered_map", reporter.errors()[1]);
+}
+
+TEST(ErrorReporterTest, UnnamedContext) {
+  ErrorReporter reporter;
+  reporter.Push();
+  reporter.AddError("lp0 is on fire");
+  reporter.Pop();
+  EXPECT_TRUE(reporter.HasErrors());
+  EXPECT_EQ(1u, reporter.errors().size());
+  EXPECT_EQ("lp0 is on fire", reporter.errors()[0]);
+}
+
+TEST(ErrorReporterTest, NestedContexts) {
+  ErrorReporter reporter;
+  reporter.Push();
+  reporter.SetName("ship");
+  reporter.Push();
+  reporter.SetName("front");
+  reporter.AddError("fell off");
+  reporter.Pop();
+  reporter.AddError("uh oh");
+  reporter.Pop();
+  EXPECT_TRUE(reporter.HasErrors());
+  EXPECT_EQ(2u, reporter.errors().size());
+  EXPECT_EQ("ship.front: fell off", reporter.errors()[0]);
+  EXPECT_EQ("ship: uh oh", reporter.errors()[1]);
+}
+
+}  // namespace headless