Confirm that email addresses do not appear in tag names

I've noticed them leaked onto the console though. Wonder what that's
about.

tests/functional/output_features/tagged_features/simple-steps.py

@@ -4,6 +4,15 @@ from lettuce import step
 @step(u'Given I do nothing')
 def given_i_do_nothing(step):
     pass
+
 @step(u'Then I see that the test passes')
 def then_i_see_that_the_test_passes(step):
     pass
+
+@step(u'Then I should not see "([^"]+)"')
+def then_should_not_see(step, email):
+    pass
+
+@step(u'Given some email addresses')
+def given_email_addresses(step):
+    pass

tests/functional/output_features/tagged_features/tagged_features.feature

@@ -13,3 +13,13 @@ Feature: ignore slow steps
   Scenario: this one is fast!!
     Given I do nothing
     Then I see that the test passes
+
+  Scenario: this scenario is not tagged
+    Given I do nothing
+    Then I should not see "harvey@nom.cat"
+
+  Scenario: this scenario is also not tagged
+    Given some email addresses
+        | email          |
+        | harvey@nom.cat |
+    Then I see that the test passes

tests/functional/test_subunit_output.py

@@ -167,6 +167,14 @@ def test_subunit_output_with_tags():
             'status': 'success',
             'tags': set(['fast-ish']),
         }),
+        Includes({
+            'status': 'success',
+            'tags': set(),
+        }),
+        Includes({
+            'status': 'success',
+            'tags': set(),
+        }),
     ]
 
     runner = Runner(feature_name('tagged_features'), enable_subunit=True)