Add ProcessArgumentsForPID() (process_util) and its test

util/posix/process_util_test.cc

+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/posix/process_util.h"
+
+#include <crt_externs.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+namespace {
+
+using namespace crashpad;
+
+TEST(ProcessUtil, ProcessArgumentsForPID) {
+  std::vector<std::string> argv;
+  ASSERT_TRUE(ProcessArgumentsForPID(getpid(), &argv));
+
+  // gtest argv processing scrambles argv, but it leaves argc and argv[0]
+  // intact, so test those.
+
+  int argc = static_cast<int>(argv.size());
+  int expect_argc = *_NSGetArgc();
+  EXPECT_EQ(expect_argc, argc);
+
+  ASSERT_GE(expect_argc, 1);
+  ASSERT_GE(argc, 1);
+
+  char** expect_argv = *_NSGetArgv();
+  EXPECT_EQ(std::string(expect_argv[0]), argv[0]);
+}
+
+}  // namespace