Add port option.

README.md

@@ -156,6 +156,14 @@ $ moto_server ec2
  * Running on http://127.0.0.1:5000/
 ```
 
+You can also pass the port as the second argument:
+
+```console
+$ moto_server ec2 3000
+ * Running on http://127.0.0.1:3000/
+```
+
+
 Then go to [localhost](http://localhost:5000/?Action=DescribeInstances) to see a list of running instances (it will be empty since you haven't added any yet).
 
 ## Install

moto/server.py

@@ -35,14 +35,18 @@ def configure_urls(service):
 
 
 def main(args=sys.argv):
-    if len(args) != 2:
+    if len(args) not in range(2, 4):
-        print("Usage: moto_server <service>")
+        print("Usage: moto_server <service> [port]")
         sys.exit(1)
     service_name = args[1]
     configure_urls(service_name)
+    try:
+        port = int(args[2])
+    except IndexError:
+        port = None
 
     app.testing = True
-    app.run()
+    app.run(port=port)
 
 if __name__ == '__main__':
     main()

tests/test_core/test_server.py

@@ -6,7 +6,7 @@ from moto.server import main
 
 def test_wrong_arguments():
     try:
-        main(["name", "test1", "test2"])
+        main(["name", "test1", "test2", "test3"])
         assert False, ("main() when called with the incorrect number of args"
                        " should raise a system exit")
     except SystemExit:
@@ -16,4 +16,10 @@ def test_wrong_arguments():
 @patch('moto.server.app.run')
 def test_right_arguments(app_run):
     main(["name", "s3"])
-    app_run.assert_called_once_with()
+    app_run.assert_called_once_with(port=None)
+
+
+@patch('moto.server.app.run')
+def test_port_argument(app_run):
+    main(["name", "s3", 8080])
+    app_run.assert_called_once_with(port=8080)