fix routing issue with slashes

sanic/router.py

@@ -98,10 +98,15 @@ class Router:
     def add(self, uri, methods, handler, host=None):
         # add regular version
         self._add(uri, methods, handler, host)
-        slash_is_missing = (not uri[-1].endswith('/')
+        slash_is_missing = (
-                            and not self.routes_all.get(uri + '/', False))
+            not uri[-1] == '/'
-        without_slash_is_missing = (not self.routes_all.get(uri[:-1], False)
+            and not self.routes_all.get(uri + '/', False)
-                                    and uri is not '/')
+        )
+        without_slash_is_missing = (
+            uri[-1] == '/'
+            and not self.routes_all.get(uri[:-1], False)
+            and not uri == '/'
+        )
         # add version with trailing slash
         if slash_is_missing:
             self._add(uri + '/', methods, handler, host)

tests/test_routes.py

@@ -498,6 +498,19 @@ def test_remove_inexistent_route():
     with pytest.raises(RouteDoesNotExist):
         app.remove_route('/test')
 
+def test_removing_slash():
+    app = Sanic(__name__)
+
+    @app.get('/rest/<resource>')
+    def get(_):
+        pass
+
+    @app.post('/rest/<resource>')
+    def post(_):
+        pass
+
+    assert len(app.router.routes_all.keys()) == 2
+
 
 def test_remove_unhashable_route():
     app = Sanic('test_remove_unhashable_route')