Validate yaml files with yamllint

Dockerfile

@@ -27,9 +27,10 @@ RUN \
   ;
 RUN pip3 install \
       envtpl \
-      pytest==3.6.4 \
-      pylint==1.9.2 \
       flake8==3.5.0 \
+      pylint==1.9.2 \
+      pytest==3.6.4 \
+      yamllint==1.15.0 \
     ;
 
 # Force GNUPG version 1 at path /usr/bin/gpg

test/conftest.py

@@ -28,6 +28,12 @@ def flake8_version():
     return '3.5.0'
 
 
+@pytest.fixture(scope='session')
+def yamllint_version():
+    """Version of yamllint supported"""
+    return '1.15.0'
+
+
 @pytest.fixture(scope='session')
 def tst_user():
     """Test session's user id"""

test/test_syntax.py

@@ -39,3 +39,14 @@ def test_flake8(runner, flake8_version):
         pytest.skip('Unsupported flake8 version')
     run = runner(command=['flake8', 'test'])
     assert run.success
+
+
+def test_yamllint(runner, yamllint_version):
+    """Passes yamllint"""
+    run = runner(command=['yamllint', '--version'], report=False)
+    if not run.out.strip().endswith(yamllint_version):
+        pytest.skip('Unsupported yamllint version')
+    run = runner(
+        command=['yamllint', '-s', '$(find . -name \\*.yml)'],
+        shell=True)
+    assert run.success