Install pytest and get version.

.gitlab-ci.yml

@@ -9,13 +9,14 @@ before_script:
     #- apt-get update -qq
     - which python
     - which pip3
-    - which pytest-3
     - python --version
     #- DEBIAN_FRONTEND=noninteractive apt-get -t testing install -yq python3.6
 
     #- apt-get -t testing install -y -qq python3-pip
     #- apt-get -t testing install -y -qq python3-pytest
 
+    - pip3 install pytest
+    - pytest --version
     - pip3 install https://gitlab.mpcdf.mpg.de/ievo/ctapipe-mpp/-/archive/master/ctapipe-mpp-master.tar.gz
     - pip3 install https://github.com/cta-observatory/ctapipe-extra/archive/master.tar.gz
     - pip3 install -e .
@@ -23,4 +24,4 @@ before_script:
 run_tests:
     script:
         #  - echo "Yes!"
-        - pytest-3 -vvs
+        - pytest -vvs