Home | History | Annotate | Download | only in testing
      1 // Copyright (c) 2012 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 (*TestMainFunctionPtr)();
     33 
     34 // Type for child setup functions.
     35 typedef void (*SetupFunctionPtr)();
     36 
     37 // Helper class to append a test function to the global mapping.
     38 // Used by the MULTIPROCESS_TEST_MAIN macro.
     39 class AppendMultiProcessTest {
     40  public:
     41   // |main_func_ptr| is the main function that is run in the child process.
     42   // |setup_func_ptr| is a function run when the global mapping is added.
     43   AppendMultiProcessTest(std::string test_name,
     44                          TestMainFunctionPtr main_func_ptr,
     45                          SetupFunctionPtr setup_func_ptr);
     46 };
     47 
     48 // Invoke the main function of a test previously registered with
     49 // MULTIPROCESS_TEST_MAIN()
     50 int InvokeChildProcessTest(std::string test_name);
     51 
     52 // This macro creates a global MultiProcessTest::AppendMultiProcessTest object
     53 // whose constructor does the work of adding the global mapping.
     54 #define MULTIPROCESS_TEST_MAIN(test_main) \
     55   MULTIPROCESS_TEST_MAIN_WITH_SETUP(test_main, NULL)
     56 
     57 // Same as above but lets callers specify a setup method that is run in the
     58 // child process, just before the main function is run.  This facilitates
     59 // adding a generic one-time setup function for multiple tests.
     60 #define MULTIPROCESS_TEST_MAIN_WITH_SETUP(test_main, test_setup) \
     61   int test_main(); \
     62   namespace { \
     63     multi_process_function_list::AppendMultiProcessTest \
     64     AddMultiProcessTest##_##test_main(#test_main, (test_main), (test_setup)); \
     65   } \
     66   int test_main()
     67 
     68 }  // namespace multi_process_function_list
     69 
     70 #endif  // TESTING_MULTIPROCESS_FUNC_LIST_H_
     71