Add @template_test() decorator for creating custom jinja2 tests, like existing @template_filter() for filters. Fixes #332

flask/app.py

@@ -1086,6 +1086,44 @@ class Flask(_PackageBoundObject):
         """
         self.jinja_env.filters[name or f.__name__] = f
 
+    @setupmethod
+    def template_test(self, name=None):
+        """A decorator that is used to register custom template test.
+        You can specify a name for the test, otherwise the function
+        name will be used. Example::
+
+          @app.template_test()
+          def is_prime(n):
+              if n == 2:
+                  return True
+              for i in xrange(2, int(math.ceil(math.sqrt(n))) + 1):
+                  if n % i == 0:
+                      return False
+              return True
+
+        .. versionadded:: 0.10
+
+        :param name: the optional name of the test, otherwise the
+                     function name will be used.
+        """
+        def decorator(f):
+            self.add_template_test(f, name=name)
+            return f
+        return decorator
+
+    @setupmethod
+    def add_template_test(self, f, name=None):
+        """Register a custom template test.  Works exactly like the
+        :meth:`template_test` decorator.
+
+        .. versionadded:: 0.10
+
+        :param name: the optional name of the test, otherwise the
+                     function name will be used.
+        """
+        self.jinja_env.tests[name or f.__name__] = f
+
+
     @setupmethod
     def before_request(self, f):
         """Registers a function to run before each request."""

flask/blueprints.py

@@ -209,6 +209,34 @@ class Blueprint(_PackageBoundObject):
             state.app.jinja_env.filters[name or f.__name__] = f
         self.record_once(register_template)
 
+    def app_template_test(self, name=None):
+        """Register a custom template test, available application wide.  Like
+        :meth:`Flask.template_test` but for a blueprint.
+
+        .. versionadded:: 0.10
+
+        :param name: the optional name of the test, otherwise the
+                     function name will be used.
+        """
+        def decorator(f):
+            self.add_app_template_test(f, name=name)
+            return f
+        return decorator
+
+    def add_app_template_test(self, f, name=None):
+        """Register a custom template test, available application wide.  Like
+        :meth:`Flask.add_template_test` but for a blueprint.  Works exactly
+        like the :meth:`app_template_test` decorator.
+
+        .. versionadded:: 0.10
+
+        :param name: the optional name of the test, otherwise the
+                     function name will be used.
+        """
+        def register_template(state):
+            state.app.jinja_env.tests[name or f.__name__] = f
+        self.record_once(register_template)
+
     def before_request(self, f):
         """Like :meth:`Flask.before_request` but for a blueprint.  This function
         is only executed before each request that is handled by a function of

flask/testsuite/blueprints.py

@@ -548,7 +548,7 @@ class BlueprintTestCase(FlaskTestCase):
             return s[::-1]
         app = flask.Flask(__name__)
         app.register_blueprint(bp, url_prefix='/py')
-        self.assert_('my_reverse' in  app.jinja_env.filters.keys())
+        self.assert_('my_reverse' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['my_reverse'], my_reverse)
         self.assert_equal(app.jinja_env.filters['my_reverse']('abcd'), 'dcba')
 
@@ -559,7 +559,7 @@ class BlueprintTestCase(FlaskTestCase):
         bp.add_app_template_filter(my_reverse)
         app = flask.Flask(__name__)
         app.register_blueprint(bp, url_prefix='/py')
-        self.assert_('my_reverse' in  app.jinja_env.filters.keys())
+        self.assert_('my_reverse' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['my_reverse'], my_reverse)
         self.assert_equal(app.jinja_env.filters['my_reverse']('abcd'), 'dcba')
 
@@ -570,7 +570,7 @@ class BlueprintTestCase(FlaskTestCase):
             return s[::-1]
         app = flask.Flask(__name__)
         app.register_blueprint(bp, url_prefix='/py')
-        self.assert_('strrev' in  app.jinja_env.filters.keys())
+        self.assert_('strrev' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['strrev'], my_reverse)
         self.assert_equal(app.jinja_env.filters['strrev']('abcd'), 'dcba')
 
@@ -581,7 +581,7 @@ class BlueprintTestCase(FlaskTestCase):
         bp.add_app_template_filter(my_reverse, 'strrev')
         app = flask.Flask(__name__)
         app.register_blueprint(bp, url_prefix='/py')
-        self.assert_('strrev' in  app.jinja_env.filters.keys())
+        self.assert_('strrev' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['strrev'], my_reverse)
         self.assert_equal(app.jinja_env.filters['strrev']('abcd'), 'dcba')
 
@@ -650,6 +650,114 @@ class BlueprintTestCase(FlaskTestCase):
         rv = app.test_client().get('/')
         self.assert_equal(rv.data, 'dcba')
 
+    def test_template_test(self):
+        bp = flask.Blueprint('bp', __name__)
+        @bp.app_template_test()
+        def is_boolean(value):
+            return isinstance(value, bool)
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        self.assert_('is_boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['is_boolean'], is_boolean)
+        self.assert_(app.jinja_env.tests['is_boolean'](False))
+
+    def test_add_template_test(self):
+        bp = flask.Blueprint('bp', __name__)
+        def is_boolean(value):
+            return isinstance(value, bool)
+        bp.add_app_template_test(is_boolean)
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        self.assert_('is_boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['is_boolean'], is_boolean)
+        self.assert_(app.jinja_env.tests['is_boolean'](False))
+
+    def test_template_test_with_name(self):
+        bp = flask.Blueprint('bp', __name__)
+        @bp.app_template_test('boolean')
+        def is_boolean(value):
+            return isinstance(value, bool)
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        self.assert_('boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['boolean'], is_boolean)
+        self.assert_(app.jinja_env.tests['boolean'](False))
+
+    def test_add_template_test_with_name(self):
+        bp = flask.Blueprint('bp', __name__)
+        def is_boolean(value):
+            return isinstance(value, bool)
+        bp.add_app_template_test(is_boolean, 'boolean')
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        self.assert_('boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['boolean'], is_boolean)
+        self.assert_(app.jinja_env.tests['boolean'](False))
+
+    def test_template_test_with_template(self):
+        bp = flask.Blueprint('bp', __name__)
+        @bp.app_template_test()
+        def boolean(value):
+            return isinstance(value, bool)
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_template_test_after_route_with_template(self):
+        app = flask.Flask(__name__)
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        bp = flask.Blueprint('bp', __name__)
+        @bp.app_template_test()
+        def boolean(value):
+            return isinstance(value, bool)
+        app.register_blueprint(bp, url_prefix='/py')
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_add_template_test_with_template(self):
+        bp = flask.Blueprint('bp', __name__)
+        def boolean(value):
+            return isinstance(value, bool)
+        bp.add_app_template_test(boolean)
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_template_test_with_name_and_template(self):
+        bp = flask.Blueprint('bp', __name__)
+        @bp.app_template_test('boolean')
+        def is_boolean(value):
+            return isinstance(value, bool)
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_add_template_test_with_name_and_template(self):
+        bp = flask.Blueprint('bp', __name__)
+        def is_boolean(value):
+            return isinstance(value, bool)
+        bp.add_app_template_test(is_boolean, 'boolean')
+        app = flask.Flask(__name__)
+        app.register_blueprint(bp, url_prefix='/py')
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
 
 def suite():
     suite = unittest.TestSuite()

flask/testsuite/templates/template_test.html

@@ -0,0 +1,3 @@
+{% if value is boolean %}
+    Success!
+{% endif %}

flask/testsuite/templating.py

@@ -89,7 +89,7 @@ class TemplatingTestCase(FlaskTestCase):
         @app.template_filter()
         def my_reverse(s):
             return s[::-1]
-        self.assert_('my_reverse' in  app.jinja_env.filters.keys())
+        self.assert_('my_reverse' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['my_reverse'], my_reverse)
         self.assert_equal(app.jinja_env.filters['my_reverse']('abcd'), 'dcba')
 
@@ -98,7 +98,7 @@ class TemplatingTestCase(FlaskTestCase):
         def my_reverse(s):
             return s[::-1]
         app.add_template_filter(my_reverse)
-        self.assert_('my_reverse' in  app.jinja_env.filters.keys())
+        self.assert_('my_reverse' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['my_reverse'], my_reverse)
         self.assert_equal(app.jinja_env.filters['my_reverse']('abcd'), 'dcba')
 
@@ -107,7 +107,7 @@ class TemplatingTestCase(FlaskTestCase):
         @app.template_filter('strrev')
         def my_reverse(s):
             return s[::-1]
-        self.assert_('strrev' in  app.jinja_env.filters.keys())
+        self.assert_('strrev' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['strrev'], my_reverse)
         self.assert_equal(app.jinja_env.filters['strrev']('abcd'), 'dcba')
 
@@ -116,7 +116,7 @@ class TemplatingTestCase(FlaskTestCase):
         def my_reverse(s):
             return s[::-1]
         app.add_template_filter(my_reverse, 'strrev')
-        self.assert_('strrev' in  app.jinja_env.filters.keys())
+        self.assert_('strrev' in app.jinja_env.filters.keys())
         self.assert_equal(app.jinja_env.filters['strrev'], my_reverse)
         self.assert_equal(app.jinja_env.filters['strrev']('abcd'), 'dcba')
 
@@ -164,6 +164,86 @@ class TemplatingTestCase(FlaskTestCase):
         rv = app.test_client().get('/')
         self.assert_equal(rv.data, 'dcba')
 
+    def test_template_test(self):
+        app = flask.Flask(__name__)
+        @app.template_test()
+        def boolean(value):
+            return isinstance(value, bool)
+        self.assert_('boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['boolean'], boolean)
+        self.assert_(app.jinja_env.tests['boolean'](False))
+
+    def test_add_template_test(self):
+        app = flask.Flask(__name__)
+        def boolean(value):
+            return isinstance(value, bool)
+        app.add_template_test(boolean)
+        self.assert_('boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['boolean'], boolean)
+        self.assert_(app.jinja_env.tests['boolean'](False))
+
+    def test_template_test_with_name(self):
+        app = flask.Flask(__name__)
+        @app.template_test('boolean')
+        def is_boolean(value):
+            return isinstance(value, bool)
+        self.assert_('boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['boolean'], is_boolean)
+        self.assert_(app.jinja_env.tests['boolean'](False))
+
+    def test_add_template_test_with_name(self):
+        app = flask.Flask(__name__)
+        def is_boolean(value):
+            return isinstance(value, bool)
+        app.add_template_test(is_boolean, 'boolean')
+        self.assert_('boolean' in app.jinja_env.tests.keys())
+        self.assert_equal(app.jinja_env.tests['boolean'], is_boolean)
+        self.assert_(app.jinja_env.tests['boolean'](False))
+
+    def test_template_test_with_template(self):
+        app = flask.Flask(__name__)
+        @app.template_test()
+        def boolean(value):
+            return isinstance(value, bool)
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_add_template_test_with_template(self):
+        app = flask.Flask(__name__)
+        def boolean(value):
+            return isinstance(value, bool)
+        app.add_template_test(boolean)
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_template_test_with_name_and_template(self):
+        app = flask.Flask(__name__)
+        @app.template_test('boolean')
+        def is_boolean(value):
+            return isinstance(value, bool)
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
+    def test_add_template_test_with_name_and_template(self):
+        app = flask.Flask(__name__)
+        def is_boolean(value):
+            return isinstance(value, bool)
+        app.add_template_test(is_boolean, 'boolean')
+        @app.route('/')
+        def index():
+            return flask.render_template('template_test.html', value=False)
+        rv = app.test_client().get('/')
+        self.assert_('Success!' in rv.data)
+
     def test_custom_template_loader(self):
         class MyFlask(flask.Flask):
             def create_global_jinja_loader(self):
@@ -177,7 +257,6 @@ class TemplatingTestCase(FlaskTestCase):
         rv = c.get('/')
         self.assert_equal(rv.data, 'Hello Custom World!')
 
-
     def test_iterable_loader(self):
         app = flask.Flask(__name__)
         @app.context_processor
@@ -195,8 +274,6 @@ class TemplatingTestCase(FlaskTestCase):
         self.assert_equal(rv.data, '<h1>Jameson</h1>')
 
 
-
-
 def suite():
     suite = unittest.TestSuite()
     suite.addTest(unittest.makeSuite(TemplatingTestCase))