Clean up formerly nose tests (setup -> setup_method)

[mcepl]

I think there are some remnants of nose in the test code:

 $ qd
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -2,7 +2,7 @@ import sys, os
 
 # In order to test the Flask-Script command, Flask-Script needs to be
 # installed. If this is the case, we won't be able to import from our
-# local src/flaskext directory that nose puts on sys.path, due to the
+# local src/flaskext directory that pytest puts on sys.path, due to the
 # way Flask extensions employ pkg_resources to have multiple directories
 # contribute to the same module. We fix it by manually adding the
 # directory to an already existing virtual flaskext module.
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -22,7 +22,7 @@ class TestConfigAppBound:
     """The extension is bound to a specific app.
     """
 
-    def setup(self):
+    def setup_method(self):
         self.app = Flask(__name__)
         self.env = Environment(self.app)
 
--- a/tests/test_integration.py
+++ b/tests/test_integration.py
@@ -26,8 +26,8 @@ class TestUrlAndDirectory(TempEnvironmen
     Let's test the different scenarios to ensure everything works.
     """
 
-    def setup(self):
-        TempEnvironmentHelper.setup(self)
+    def setup_method(self):
+        TempEnvironmentHelper.setup_method(self)
 
         self.app = Flask(__name__, static_url_path='/app_static')
         from tests import test_module
@@ -152,7 +152,7 @@ class TestUrlAndDirectoryWithInitApp(obj
     values also work if the application is initialized via "init_app()".
     """
 
-    def setup(self):
+    def setup_method(self):
         self.app = Flask(__name__, static_url_path='/initapp_static')
         self.env = Environment()
         self.env.init_app(self.app)
 $