[Extensions Bindings] Add argument parsing errors

extensions/renderer/api_invocation_errors_unittest.cc

+// Copyright 2017 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 "extensions/renderer/api_invocation_errors.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace extensions {
+namespace api_errors {
+
+// Tests chaining errors for more complicated errors. More of a set of example
+// strings than a test of the logic itself (which is pretty simple).
+TEST(APIInvocationErrors, ChainedErrors) {
+  EXPECT_EQ("Error at index 0: Invalid type: expected string, found integer.",
+            IndexError(0, InvalidType(kTypeString, kTypeInteger)));
+  EXPECT_EQ(
+      "Error at property 'foo': Invalid type: expected string, found integer.",
+      PropertyError("foo", InvalidType(kTypeString, kTypeInteger)));
+  EXPECT_EQ(
+      "Error at property 'foo': Error at index 1: "
+      "Invalid type: expected string, found integer.",
+      PropertyError("foo",
+                    IndexError(1, InvalidType(kTypeString, kTypeInteger))));
+}
+
+}  // namespace api_errors
+}  // namespace extensions