check the base if passed

\n(feature/185_catch_gitcommand_error_on_non_existant_remote_target)

tests/test_dev.py

@@ -259,6 +259,18 @@ def test_review(mocker, git_repo):
         assert result.exit_code == 0
 
 
+def test_review_no_base(mocker, git_repo):
+    mocked_reviewer = mocker.Mock()
+    mocked_reviewer.review = mocker.Mock(return_value=[])
+    mocked_reviewer.create_review = mocker.Mock()
+    mocker.patch('zazu.config.Config.code_reviewer', return_value=mocked_reviewer)
+    with zazu.util.cd(git_repo.working_tree_dir):
+        runner = click.testing.CliRunner()
+        result = runner.invoke(zazu.cli.cli, ['dev', 'review', '--base', 'does-not-exist'])
+        assert result.exception
+        assert result.exit_code == 1
+
+
 def test_review_existing(mocker, git_repo):
     mocker.patch('webbrowser.open_new')
     mocked_tracker = mocker.Mock()

zazu/dev/commands.py

@@ -304,6 +304,11 @@ def review(config, base, head):
     """Create or display pull request."""
     code_reviewer = config.code_reviewer()
     head = config.repo.active_branch.name if head is None else head
+    if base is not None:
+        try:
+            config.repo.git.show_branch('remotes/origin/{}'.format(base))
+        except git.exc.GitCommandError as e:
+                raise click.ClickException('failed to find remote branch: {}'.format(str(base)))
     existing_reviews = code_reviewer.review(status='open', head=head, base=base)
     if existing_reviews:
         pr = zazu.util.pick(existing_reviews, 'Multiple reviews found, pick one')