mojo/core/test/multiprocess_test_helper.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MOJO_CORE_TEST_MULTIPROCESS_TEST_HELPER_H_
#define MOJO_CORE_TEST_MULTIPROCESS_TEST_HELPER_H_

#include <string>

#include "base/functional/callback.h"
#include "base/process/process.h"
#include "base/test/multiprocess_test.h"
#include "base/test/test_timeouts.h"
#include "build/build_config.h"
#include "mojo/public/cpp/system/message_pipe.h"
#include "testing/multiprocess_func_list.h"

namespace mojo {

class IsolatedConnection;

namespace core {
namespace test {

class MultiprocessTestHelper {
 public:
  enum class LaunchType {
    // Launch the child process as a child in the mojo system.
    CHILD,

    // Launch the child process as an unrelated peer process in the mojo system.
    PEER,

    // Same as CHILD but uses the newer async channel handshake.
    ASYNC,

#if !BUILDFLAG(IS_FUCHSIA) && !BUILDFLAG(IS_IOS)
    // Launch the child process as a child in the mojo system, using a named
    // pipe.
    NAMED_CHILD,

    // Launch the child process as an unrelated peer process in the mojo
    // system, using a named pipe.
    NAMED_PEER,
#endif  //  !BUILDFLAG(IS_FUCHSIA) && !BUILDFLAG(IS_IOS)
    // This is the same as child; however, it will never advertise any
    // capabilities.
    CHILD_WITHOUT_CAPABILITIES
  };

  MultiprocessTestHelper();

  MultiprocessTestHelper(const MultiprocessTestHelper&) = delete;
  MultiprocessTestHelper& operator=(const MultiprocessTestHelper&) = delete;

  ~MultiprocessTestHelper();

  // Start a child process and run the "main" function "named" |test_child_name|
  // declared using |MOJO_MULTIPROCESS_TEST_CHILD_MAIN()| or
  // |MOJO_MULTIPROCESS_TEST_CHILD_TEST()| (below).
  ScopedMessagePipeHandle StartChild(
      const std::string& test_child_name,
      LaunchType launch_type = LaunchType::CHILD);

  // Like |StartChild()|, but appends an extra switch (with ASCII value) to the
  // command line. (The switch must not already be present in the default
  // command line.)
  ScopedMessagePipeHandle StartChildWithExtraSwitch(
      const std::string& test_child_name,
      const std::string& switch_string,
      const std::string& switch_value,
      LaunchType launch_type);

  // Wait for the child process to terminate.
  // Returns the exit code of the child process. Note that, though it's declared
  // to be an |int|, the exit code is subject to mangling by the OS. E.g., we
  // usually return -1 on error in the child (e.g., if |test_child_name| was not
  // found), but this is mangled to 255 on Linux. You should only rely on codes
  // 0-127 being preserved, and -1 being outside the range 0-127.
  int WaitForChildShutdown();

  // Like |WaitForChildShutdown()|, but returns true on success (exit code of 0)
  // and false otherwise. You probably want to do something like
  // |EXPECT_TRUE(WaitForChildTestShutdown());|.
  bool WaitForChildTestShutdown();

  const base::Process& test_child() const { return test_child_; }

  // Used by macros in mojo/core/test/mojo_test_base.h to support multiprocess
  // test client initialization.
  static void ChildSetup();
  static int RunClientMain(base::OnceCallback<int(MojoHandle)> main,
                           bool pass_pipe_ownership_to_main = false);
  static int RunClientTestMain(base::OnceCallback<void(MojoHandle)> main);

  // For use (and only valid) in the child process:
  static mojo::ScopedMessagePipeHandle primordial_pipe;

 private:
  // Valid after |StartChild()| and before |WaitForChildShutdown()|.
  base::Process test_child_;

  std::unique_ptr<IsolatedConnection> isolated_connection_;
};

}  // namespace test
}  // namespace core
}  // namespace mojo

#endif  // MOJO_CORE_TEST_MULTIPROCESS_TEST_HELPER_H_