specified baseline path in tox

Author: ruaridhg

tox.ini

@@ -19,4 +19,4 @@ commands =
     cp -R {toxinidir}/src/napari_matplotlib/tests/baseline {envdir}/baseline
     ls {toxinidir}/src/napari_matplotlib/tests/baseline
     python -c 'from skimage import data; data.brain()'
-    python -m pytest --mpl --mpl-generate-summary=html --mpl-results-path={toxinidir}/reports -v --color=yes --cov=napari_matplotlib --cov-report=xml
+    python -m pytest --mpl --mpl-baseline-path={toxinidir}/src/napari_matplotlib/tests/baseline --mpl-generate-summary=html --mpl-results-path={toxinidir}/reports -v --color=yes --cov=napari_matplotlib --cov-report=xml