add trivial test for cli tool version argument

Author: ikirudennis

tests/test_cli.py

@@ -2,6 +2,8 @@
 import subprocess
 import sys
 
+import textile
+
 def test_console_script():
     command = [sys.executable, '-m', 'textile', 'README.textile']
     try:
@@ -15,3 +17,13 @@ def test_console_script():
     if type(result) == bytes:
         result = result.decode('utf-8')
     assert result == expect
+
+def test_version_string():
+    command = [sys.executable, '-m', 'textile', '-v']
+    try:
+        result = subprocess.check_output(command)
+    except AttributeError:
+        command[2] = 'textile.__main__'
+        result = subprocess.Popen(command,
+                stdout=subprocess.PIPE).communicate()[0]
+    assert result.strip() == textile.__version__