Added simple test for plain module

tests/test_plain.py

@@ -0,0 +1,18 @@
+from unittest import TestCase
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+from fs_uae_wrapper import plain
+from fs_uae_wrapper import utils
+
+
+class TestPlainModule(TestCase):
+
+    @mock.patch('subprocess.call')
+    def test_show(self, subprocess_call):
+
+        plain.run('some.conf', utils.CmdOption(), None)
+        subprocess_call.assert_called_once()