For slow builders

--- a/tests/test_pytest_mypy.py
+++ b/tests/test_pytest_mypy.py
@@ -479,7 +479,7 @@ def test_looponfail(testdir, module_name):
 
     child = testdir.spawn_pytest(
         "--mypy --looponfail " + str(pyfile),
-        expect_timeout=60.0,
+        expect_timeout=300.0,
     )
 
     def _expect_session():