Made (make|compile)messages check for availability of gettext commands.

Refs #19584.

tests/i18n/commands/extraction.py

@@ -131,8 +131,13 @@ class BasicExtractorTests(ExtractorTests):
         os.chdir(self.test_dir)
         shutil.copyfile('./code.sample', './code_sample.py')
         stdout = StringIO()
-        management.call_command('makemessages', locale=LOCALE, stdout=stdout)
-        os.remove('./code_sample.py')
+        try:
+            management.call_command('makemessages', locale=LOCALE, stdout=stdout)
+        finally:
+            try:
+                os.remove('./code_sample.py')
+            except OSError:
+                pass
         self.assertIn("code_sample.py:4", force_text(stdout.getvalue()))
 
     def test_template_message_context_extractor(self):

tests/i18n/commands/tests.py

@@ -2,35 +2,11 @@ import os
 import re
 from subprocess import Popen, PIPE
 
-from django.utils import six
+from django.core.management.utils import find_command
 
 can_run_extraction_tests = False
 can_run_compilation_tests = False
 
-def find_command(cmd, path=None, pathext=None):
-    if path is None:
-        path = os.environ.get('PATH', []).split(os.pathsep)
-    if isinstance(path, six.string_types):
-        path = [path]
-    # check if there are funny path extensions for executables, e.g. Windows
-    if pathext is None:
-        pathext = os.environ.get('PATHEXT', '.COM;.EXE;.BAT;.CMD').split(os.pathsep)
-    # don't use extensions if the command ends with one of them
-    for ext in pathext:
-        if cmd.endswith(ext):
-            pathext = ['']
-            break
-    # check if we find the command on PATH
-    for p in path:
-        f = os.path.join(p, cmd)
-        if os.path.isfile(f):
-            return f
-        for ext in pathext:
-            fext = f + ext
-            if os.path.isfile(fext):
-                return fext
-    return None
-
 # checks if it can find xgettext on the PATH and
 # imports the extraction tests if yes
 xgettext_cmd = find_command('xgettext')

tests/user_commands/tests.py

@@ -1,13 +1,14 @@
 import sys
 
 from django.core import management
-from django.core.management.base import CommandError
-from django.test import TestCase
+from django.core.management import CommandError
+from django.core.management.utils import popen_wrapper
+from django.test import SimpleTestCase
 from django.utils import translation
 from django.utils.six import StringIO
 
 
-class CommandTests(TestCase):
+class CommandTests(SimpleTestCase):
     def test_command(self):
         out = StringIO()
         management.call_command('dance', stdout=out)
@@ -58,3 +59,9 @@ class CommandTests(TestCase):
         with translation.override('pl'):
             management.call_command('leave_locale_alone_true', stdout=out)
             self.assertEqual(out.getvalue(), "pl\n")
+
+
+class UtilsTests(SimpleTestCase):
+
+    def test_no_existent_external_program(self):
+        self.assertRaises(CommandError, popen_wrapper, ['a_42_command_that_doesnt_exist_42'])