GLib.test_trap_subprocess_with_envp
Description: Reference for GLib.test_trap_subprocess_with_envp

### Function

# GLibtest_trap_subprocess_with_envp

since: 2.80

#### Declaration [src]

    void
    g_test_trap_subprocess_with_envp (
      const char* test_path,
      const char* const* envp,
      guint64 usec_timeout,
      GTestSubprocessFlags test_flags
    )

#### Description [src]

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 `g_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 `GTestSubprocessFlags` flags.

You can use methods such as `g_test_trap_assert_passed()`, `g_test_trap_assert_failed()`, and `g_test_trap_assert_stderr()` to check the results of the subprocess. (But note that `g_test_trap_assert_stdout()` and `g_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 `g_test_subprocess()` (after calling `g_test_init()`) to see whether you are in a subprocess.

Internally, this function tracks the child process using `g_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 ();
      }

Available since: 2.80

#### Parameters

`test_path`

  Type: `const char*`

  Test to run in a subprocess.

  The argument can be `NULL`.
  The data is owned by the caller of the function.
  The value is a NUL terminated UTF-8 string.

`envp`

  Type: An array of `filename`

  Environment to run the test in.

  The argument can be `NULL`.
  The array must be `NULL`-terminated.
  The data is owned by the caller of the function.
  Each element is a platform-native string, using the preferred OS encoding on Unix and UTF-8 on Windows.

`usec_timeout`

  Type: `guint64`

  Timeout for the subprocess test in microseconds.

`test_flags`

  Type: `GTestSubprocessFlags`

  Flags to modify subprocess behaviour.