docs: Replace py.test with pytest

Fixes coala#4189

docs/Developers/Executing_Tests.rst

@@ -34,10 +34,10 @@ You can then execute our tests with
 
 ::
 
-    $ py.test
+    $ pytest
 
 .. note::
-    If ``py.test`` seems to give errors, try running ``python3 -m pytest``
+    If ``pytest`` seems to give errors, try running ``python3 -m pytest``
     instead.
 
 and report any errors you get!
@@ -48,11 +48,11 @@ To run our tests, you can also use ``python3 setup.py test``
 
     If you need to customize test running, you can get more options
     about allowing skipped tests, getting code coverage displayed
-    or omitting/selecting tests using ``py.test`` directly.
+    or omitting/selecting tests using ``pytest`` directly.
 
     ::
 
-        $ py.test --help
+        $ pytest --help
 
 .. note::
 
@@ -66,12 +66,12 @@ To get coverage information, you can run:
 
 ::
 
-    $ py.test --cov
+    $ pytest --cov
 
 You can view the coverage report as html by running:
 
 ::
 
-    $ py.test --cov --cov-report html
+    $ pytest --cov --cov-report html
 
 The html report will be saved ``.htmlreport`` inside the coala repository.

docs/Developers/Writing_Tests.rst

@@ -30,28 +30,27 @@ automatically executed by running:
 
 ::
 
-    $ py.test
+    $ pytest
 
 There's only one constraint:
 The name of the test file has to end with ``Test.py`` (for example
 ``MyCustomTest.py``, but not ``MyCustomTestSuite.py``).
 
 .. note::
-    If ``py.test`` seems to give errors, try running ``python3 -m pytest``
+    If ``pytest`` seems to give errors, try running ``python3 -m pytest``
     instead.
 
-.. note::
 
     Often you don't want to run all available tests. To run your
     specific one, type (in the coala root folder):
 
     .. code:: shell
 
-        $ py.test -k <your-test>
+        $ pytest -k <your-test>
 
     You can even give partial names or queries like "not MyCustomTest"
     to not run a specific test. More information can be got with
-    ``py.test -h``
+    ``pytest -h``
 
 Coming to the test file structure. Every test script starts with your
 imports. According to the coala code style (and pep8 style) we first do
@@ -129,7 +128,7 @@ So an example test that succeeds would be:
 
 
     The branch coverage can be measured locally with the
-    ``py.test --cov`` command.
+    ``pytest --cov`` command.
 
     .. seealso::
 
@@ -187,7 +186,7 @@ as a kickstart for test-writing.
 
 Put the code under the desired folder inside ``tests``,
 modify it to let it test your stuff and run the test from
-the coala root folder ``py.test``.
+the coala root folder ``pytest``.
 
 .. code:: python