type annotation and spread out implementation to see if it's crashing

This commit was sponsored by Matt Campbell, hacklschorsch, and my
other patrons.  If you want to join them, you can support my work at
https://glyph.im/patrons/.

automat/_test/test_visualize.py

@@ -252,12 +252,14 @@ class IntegrationTests(TestCase):
     Automat.
     """
 
-    def test_validGraphviz(self):
+    def test_validGraphviz(self) -> None:
         """
         C{graphviz} emits valid graphviz data.
         """
+        digraph = sampleMachine().asDigraph()
+        text = "".join(digraph).encode("utf-8")
         p = subprocess.Popen("dot", stdin=subprocess.PIPE, stdout=subprocess.PIPE)
-        out, err = p.communicate("".join(sampleMachine().asDigraph()).encode("utf-8"))
+        out, err = p.communicate(text)
         self.assertEqual(p.returncode, 0)
 
 

tox.ini

@@ -15,7 +15,7 @@ deps =
     pytest
 
 commands =
-    {extras,noextras}: coverage run --parallel --source automat -m pytest -rfEsx automat/_test
+    {extras,noextras}: coverage run --parallel --source automat -m pytest -s -rfEsx automat/_test
     mypy: mypy {posargs:automat}
 
 depends =