rework travis file

.travis.yml

@@ -1,23 +1,27 @@
 language: python
-python:
-    - "2.7"
-    - "3.4"
-    - "3.5"
-    - "3.6"
-    - "pypy"
-    - "pypy3"
+os: linux
+
 jobs:
   include:
+    - python: 2.7
+      install:
+          - pip install -r requirements_py2.txt
+          - pip install coveralls==1.1
+          - pip install scrutinizer-ocular
+    - python: 3.4
+    - python: 3.5
+    - python: 3.6
     - python: 3.7
-      os: linux
     - python: 3.8
-      os: linux
+    - python: "pypy"
+    - python: "pypy3"
+
 install:
-    - make init
-    - pip install coveralls==1.1
+    - pip install -r requirements_py3.txt
+    - pip install coveralls
     - pip install scrutinizer-ocular
 script:
-    make test
+    - PYTHONHASHSEED=0 python -m pytest --cov=vdf tests
 after_success:
     - coveralls
     - ocular --data-file ".coverage"

Makefile

@@ -16,7 +16,7 @@ help:
 	@echo "$$HELPBODY"
 
 init:
-	pip install -r requirements.txt
+	pip install -r requirements_py2.txt
 
 test:
 	rm -f .coverage vdf/*.pyc tests/*.pyc

requirements_py3.txt

@@ -0,0 +1,3 @@
+mock
+pytest
+pytest-cov