Allow unittests-nodisp to run w/o DISPLAY on CI.

tests/conftest.py

@@ -61,7 +61,8 @@ def pytest_collection_modifyitems(items):
         if 'qapp' in getattr(item, 'fixturenames', ()):
             item.add_marker('gui')
             if sys.platform == 'linux' and not os.environ.get('DISPLAY', ''):
-                if 'CI' in os.environ:
+                if ('CI' in os.environ and
+                        not os.environ.get('QUTE_NO_DISPLAY_OK', '')):
                     raise Exception("No display available on CI!")
                 skip_marker = pytest.mark.skipif(
                     True, reason="No DISPLAY available")

tox.ini

@@ -66,7 +66,9 @@ commands =
 basepython = python3
 passenv = {[testenv]passenv}
 deps = {[testenv]deps}
-setenv = DISPLAY=
+setenv =
+    DISPLAY=
+    QUTE_NO_DISPLAY_OK=1
 commands =
     {envpython} scripts/link_pyqt.py --tox {envdir}
     {envpython} -m py.test --strict -rfEsw -m 'not integration' {posargs:tests}