- Properly define pytest as an extra dependency

.gitignore

@@ -3,3 +3,4 @@
 /.idea/
 /tiffwrite.egg-info/
 /.pytest_cache/
+/venv/

pyproject.toml

@@ -20,9 +20,10 @@ numpy = "*"
 tqdm = "*"
 colorcet = "*"
 matplotlib = "*"
+pytest = { version = "*", optional = true }
 
-[tool.poetry.group.test.dependencies]
+[tool.poetry.extras]
-pytest = "*"
+test = ["pytest"]
 
 [build-system]
 requires = ["poetry-core"]