README.md in trackler-2.2.1.111

- old
+ new

@@ -64,16 +64,34 @@
 indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
 every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
 a message.
 
 To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
-`raise Exception`, you shold write:
+`raise Exception`, you should write:
 
 ```python
 raise Exception("Meaningful message indicating the source of the error")
 ```
 
+## Running the tests
+
+To run the tests, run the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
+
+- Python 2.7: `py.test transpose_test.py`
+- Python 3.3+: `pytest transpose_test.py`
+
+Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
+`python -m pytest transpose_test.py`
+
+### Common `pytest` options
+
+- `-v` : enable verbose output
+- `-x` : stop running tests on first failure
+- `--ff` : run failures from previous test before running other test cases
+
+For other options, see `python -m pytest -h`
+
 ## Submitting Exercises
 
 Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/transpose` directory.
 
 You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
@@ -84,6 +102,7 @@
 ## Source
 
 Reddit r/dailyprogrammer challenge #270 [Easy]. [https://www.reddit.com/r/dailyprogrammer/comments/4msu2x/challenge_270_easy_transpose_the_input_text](https://www.reddit.com/r/dailyprogrammer/comments/4msu2x/challenge_270_easy_transpose_the_input_text)
 
 ## Submitting Incomplete Solutions
+
 It's possible to submit an incomplete solution so you can see how others have completed the exercise.