add test requirements

.github/workflows/pythonpackage.yml

@@ -21,23 +21,19 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -r requirements.txt
+        pip install -r requirements.test.txt
     - name: Lint with flake8
       run: |
-        pip install flake8
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         flake8 . --count --exit-zero --max-complexity=15 --max-line-length=127 --statistics
     - name: Test with pytest
       run: |
-        pip install pytest
-        pip install pytest-cov
         pytest -s --cov=gestalt tests/*.py
     - name: Typecheck with mypy
       run: |
-        pip install mypy
         mypy --strict gestalt
     - name: Style check with yapf
       run: |
-        pip install yapf
         yapf -d --recursive .

requirements.test.txt

@@ -0,0 +1,6 @@
+yapf==0.29.0
+flake8==3.7.9
+mypy==0.720
+mypy-extensions==0.4.1
+pytest==4.3.1
+pytest-cov==2.8.1