Merge lp:~james-w/pkgme/informative-skip-message into lp:pkgme

[James Westby]

Hi,

This adds a helper for requiring a command for a test method.

It's main use it to give an informative error message with little typing.

It's used to make the one use of require_command with skipTest be more
informative.

Thanks,

James

[Jonathan Lange (jml)]

This is good. I would probably have implemented it as, well, anything other than a mixin. e.g. testtools provides @skipIf and @skipUnless decorators. They wouldn't be as informative as this, but you could build something more informative from them.

Huh. I guess this is a useful prompt for testtools to have something to make this easier, much like bzr's feature thing.

Anyway, I'd be happy merging this.

review: Approve

=== modified file 'pkgme/testing.py'
--- pkgme/testing.py	2010-12-18 14:40:42 +0000
+++ pkgme/testing.py	2011-07-01 02:04:33 +0000
@@ -205,3 +205,18 @@
         return str(error)
     else:
         return None
+
+
+class CommandRequiredTestCase(object):
+
+    def skipTestIfCommandNotExecutable(self, command_name):
+        """Skip the test if a particular command can't be run.
+
+        Try running the passed command, and if it fails then skip the test.
+        :param command_name: the name of the command to check
+        :return: None
+        :raises: TestSkipped if command_name can't be run.
+        """
+        find_error = require_command(command_name)
+        if find_error is not None:
+            self.skipTest("'%s' not executable: %s" % (command_name, find_error))

=== modified file 'pkgme/tests/test_vala_backend.py'
--- pkgme/tests/test_vala_backend.py	2011-01-16 19:04:50 +0000
+++ pkgme/tests/test_vala_backend.py	2011-07-01 02:04:33 +0000
@@ -24,14 +24,14 @@
 from testtools import TestCase
 
 from pkgme.backend import ExternalHelpersBackend, get_backend_dir
-from pkgme.testing import TempdirFixture, require_command
+from pkgme.testing import CommandRequiredTestCase, TempdirFixture
 from pkgme.write import write_file
 
 
 backend_dir = get_backend_dir(__file__, 'vala')
 
 
-class ValaBackendTests(TestCase, TestWithFixtures):
+class ValaBackendTests(TestCase, TestWithFixtures, CommandRequiredTestCase):
 
     def setUp(self):
         super(ValaBackendTests, self).setUp()
@@ -88,9 +88,7 @@
             {"buildsystem": "autoconf"}, info.get_all(["buildsystem"]))
 
     def test_build_depends(self):
-        find_error = require_command('vala-dep-scanner')
-        if find_error is not None:
-            self.skipTest(find_error)
+        self.skipTestIfCommandNotExecutable('vala-dep-scanner')
         self.write_file_in_tempdir("main.vala", "Gtk.Window win;")
         info = self.get_info()
         self.assertEqual(