testing/multiprocess_func_list.h

   1 // Copyright (c) 2008 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef TESTING_MULTIPROCESS_FUNC_LIST_H_
   6 #define TESTING_MULTIPROCESS_FUNC_LIST_H_
   7
   8 #include <string>
   9
  10 // This file provides the plumbing to register functions to be executed
  11 // as the main function of a child process in a multi-process test.
  12 // This complements the MultiProcessTest class which provides facilities
  13 // for launching such tests.
  14 //
  15 // The MULTIPROCESS_TEST_MAIN() macro registers a string -> func_ptr mapping
  16 // by creating a new global instance of the AppendMultiProcessTest() class
  17 // this means that by the time that we reach our main() function the mapping
  18 // is already in place.
  19 //
  20 // Example usage:
  21 //  MULTIPROCESS_TEST_MAIN(a_test_func) {
  22 //    // Code here runs in a child process.
  23 //    return 0;
  24 //  }
  25 //
  26 // The prototype of a_test_func is implicitly
  27 //   int test_main_func_name();
  28
  29 namespace multi_process_function_list {
  30
  31 // Type for child process main functions.
  32 typedef int (*ChildFunctionPtr)();
  33
  34 // Helper class to append a test function to the global mapping.
  35 // Used by the MULTIPROCESS_TEST_MAIN macro.
  36 class AppendMultiProcessTest {
  37  public:
  38   AppendMultiProcessTest(std::string test_name, ChildFunctionPtr func_ptr);
  39 };
  40
  41 // Invoke the main function of a test previously registered with
  42 // MULTIPROCESS_TEST_MAIN()
  43 int InvokeChildProcessTest(std::string test_name);
  44
  45 // This macro creates a global MultiProcessTest::AppendMultiProcessTest object
  46 // whose constructor does the work of adding the global mapping.
  47 #define MULTIPROCESS_TEST_MAIN(test_main) \
  48   int test_main(); \
  49   namespace { \
  50     multi_process_function_list::AppendMultiProcessTest \
  51     AddMultiProcessTest##_##test_main(#test_main, (test_main)); \
  52   } \
  53   int test_main()
  54
  55 }  // namespace multi_process_function_list
  56
  57 #endif  // TESTING_MULTIPROCESS_FUNC_LIST_H_