GLib-2.0 ▶ GLib ▶ test_trap_subprocess_with_envpSince 2.80

Respawns the test program to run only test_path in a subprocess with a given environment.

This can be used for a test case that might not return, or that might abort.

If test_path is NULL then the same test is re-run in a subprocess. You can use GLib.test_subprocess to determine whether the test is in a subprocess or not.

test_path can also be the name of the parent test, followed by "/subprocess/" and then a name for the specific subtest (or just ending with "/subprocess" if the test only has one child test); tests with names of this form will automatically be skipped in the parent process.

If envp is NULL, the parent process’ environment will be inherited.

If usec_timeout is non-0, the test subprocess is aborted and considered failing if its run time exceeds it.

The subprocess behavior can be configured with GLib.TestSubprocessFlags flags.

You can use methods such as GLib.test_trap_assert_passed, GLib.test_trap_assert_failed, and GLib.test_trap_assert_stderr to check the results of the subprocess. (But note that GLib.test_trap_assert_stdout and GLib.test_trap_assert_stderr cannot be used if test_flags specifies that the child should inherit the parent stdout/stderr.)

If your main () needs to behave differently in the subprocess, you can call GLib.test_subprocess (after calling GLib.test_init) to see whether you are in a subprocess.

Internally, this function tracks the child process using GLib.child_watch_source_new, so your process must not ignore SIGCHLD, and must not attempt to watch or wait for the child process via another mechanism.

The following example tests that calling my_object_new(1000000) will abort with an error message.

  static void
  test_create_large_object (void)
  {
    if (g_test_subprocess ())
      {
        my_object_new (1000000);
        return;
      }

    // Reruns this same test in a subprocess
    g_test_trap_subprocess (NULL, 0, G_TEST_SUBPROCESS_DEFAULT);
    g_test_trap_assert_failed ();
    g_test_trap_assert_stderr ("*ERROR*too large*");
  }

  static void
  test_different_username (void)
  {
    if (g_test_subprocess ())
      {
        // Code under test goes here
        g_message ("Username is now simulated as %s", g_getenv ("USER"));
        return;
      }

    // Reruns this same test in a subprocess
    g_auto(GStrv) envp = g_get_environ ();
    envp = g_environ_setenv (g_steal_pointer (&envp), "USER", "charlie", TRUE);
    g_test_trap_subprocess_with_envp (NULL, envp, 0, G_TEST_SUBPROCESS_DEFAULT);
    g_test_trap_assert_passed ();
    g_test_trap_assert_stdout ("Username is now simulated as charlie");
  }

  int
  main (int argc, char **argv)
  {
    g_test_init (&argc, &argv, NULL);

    g_test_add_func ("/myobject/create-large-object",
                     test_create_large_object);
    g_test_add_func ("/myobject/different-username",
                     test_different_username);
    return g_test_run ();
  }
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