Pyflakes should run on the testsuite too

.gitlab-ci.yml

@@ -16,7 +16,7 @@ pyflakes:
   script:
   - apt-get -qqy update
   - apt-get -qqy install --no-install-recommends pyflakes3
-  - pyflakes3 ./libmat2
+  - pyflakes3 ./libmat2 ./mat2 ./tests/
 
 mypy:
   stage: linting