Explain pytest --runslow

tests/conftest.py

@@ -173,7 +173,9 @@ def first_page_dimensions(pdf):
 
 def pytest_addoption(parser):
     parser.addoption(
-        "--runslow", action="store_true", default=False, help="run slow tests"
+        "--runslow", action="store_true", default=False,
+        help=("run slow tests only useful for development (unlikely to be "
+              "useful for downstream packagers)")
     )
 
 

tests/test_rotation.py

@@ -89,6 +89,7 @@ def test_monochrome_correlation(resources, outdir):
     assert corr > 0.90
 
 
+@pytest.mark.slow
 @pytest.mark.parametrize('renderer', RENDERERS)
 def test_autorotate(spoof_tesseract_cache, renderer, resources, outdir):
     # cardinal.pdf contains four copies of an image rotated in each cardinal