README.md in trackler-2.2.1.111

- old
+ new

@@ -5,14 +5,14 @@
 Pig Latin is a made-up children's language that's intended to be
 confusing. It obeys a few simple rules (below), but when it's spoken
 quickly it's really difficult for non-children (and non-native speakers)
 to understand.
 
-- **Rule 1**: If a word begins with a vowel sound, add an "ay" sound to
-  the end of the word.
-- **Rule 2**: If a word begins with a consonant sound, move it to the
-  end of the word, and then add an "ay" sound to the end of the word.
+- **Rule 1**: If a word begins with a vowel sound, add an "ay" sound to the end of the word. Please note that "xr" and "yt" at the beginning of a word make vowel sounds (e.g. "xray" -> "xrayay", "yttria" -> "yttriaay").
+- **Rule 2**: If a word begins with a consonant sound, move it to the end of the word and then add an "ay" sound to the end of the word. Consonant sounds can be made up of multiple consonants, a.k.a. a consonant cluster (e.g. "chair" -> "airchay").
+- **Rule 3**: If a word starts with a consonant sound followed by "qu", move it to the end of the word, and then add an "ay" sound to the end of the word (e.g. "square" -> "aresquay").
+- **Rule 4**: If a word contains a "y" after a consonant cluster or as the second letter in a two letter word it makes a vowel sound (e.g. "rhythm" -> "ythmrhay", "my" -> "ymay").
 
 There are a few more rules for edge cases, and there are regional
 variants too.
 
 See <http://en.wikipedia.org/wiki/Pig_latin> for more details.
@@ -23,16 +23,34 @@
 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 pig_latin_test.py`
+- Python 3.3+: `pytest pig_latin_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 pig_latin_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/pig-latin` directory.
 
 You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
@@ -43,6 +61,7 @@
 ## Source
 
 The Pig Latin exercise at Test First Teaching by Ultrasaurus [https://github.com/ultrasaurus/test-first-teaching/blob/master/learn_ruby/pig_latin/](https://github.com/ultrasaurus/test-first-teaching/blob/master/learn_ruby/pig_latin/)
 
 ## Submitting Incomplete Solutions
+
 It's possible to submit an incomplete solution so you can see how others have completed the exercise.