Git alias fix for windows and tests (#626)

* Git alias fix for windows and tests

* Fix the alias expression for python 2 compliance

* Add tests

azure-devops/azext_devops/dev/common/git.py

@@ -190,7 +190,8 @@ def _get_alias_key(alias):
 
 
 def _get_alias_value(command):
-    return '!f() { exec az ' + command + ' \"$@\"; }; f'
+    mime = '.cmd' if sys.platform.lower().startswith('win') else ''
+    return '!f() { exec az' + mime + ' ' + command + ' \"$@\"; }; f'
 
 
 _git_remotes = {}

tests/test_gitAliasTest.py

@@ -0,0 +1,12 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+import subprocess
+from azure.cli.testsdk import ScenarioTest
+
+class TestGitAliasing(ScenarioTest):
+    def test_git_aliases_pr_repo(self):
+        self.cmd('az devops configure --use-git-aliases')
+        repo_help = subprocess.check_output('git repo -h', shell=True)
+        pr_help = subprocess.check_output('git pr -h', shell=True)