Unify error messages

Unify error messages for CLI

Unify error messages for hub

Fixes: https://pagure.io/koji/issue/2720

tests/test_cli/test_remove_target.py

@@ -0,0 +1,37 @@
+from __future__ import absolute_import
+
+import mock
+from six.moves import StringIO
+
+import koji
+from koji_cli.commands import handle_remove_target
+from . import utils
+
+
+class TestRemoveTarget(utils.CliTestCase):
+    def setUp(self):
+        self.options = mock.MagicMock()
+        self.options.debug = False
+        self.session = mock.MagicMock()
+        self.session.getAPIVersion.return_value = koji.API_VERSION
+
+    @mock.patch('sys.stderr', new_callable=StringIO)
+    def test_remove_target_without_option(self, stderr):
+        expected = "Usage: %s remove-target [options] <name>\n" \
+                   "(Specify the --help global option for a list of other help options)\n\n" \
+                   "%s: error: Please specify a build target to " \
+                   "remove\n" % (self.progname, self.progname)
+        with self.assertRaises(SystemExit) as ex:
+            handle_remove_target(self.options, self.session, [])
+        self.assertExitCode(ex, 2)
+        self.assert_console_message(stderr, expected)
+
+    @mock.patch('sys.stderr', new_callable=StringIO)
+    def test_remove_target_non_exist_target(self, stderr):
+        target = 'test-target'
+        expected = "No such build target: %s\n" % target
+        self.session.getBuildTarget.return_value = None
+        with self.assertRaises(SystemExit) as ex:
+            handle_remove_target(self.options, self.session, [target])
+        self.assertExitCode(ex, 1)
+        self.assert_console_message(stderr, expected)