diff --git a/.travis.yml b/.travis.yml
index 0b339e2..da56428 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,10 @@
 language: python
+dist: xenial
 sudo: false
 python:
-  - "3.4"
   - "3.5"
   - "3.6"
+  - "3.7"
 
 install:
   - python setup.py install
diff --git a/aiohttp_swagger/__init__.py b/aiohttp_swagger/__init__.py
index 828dc28..b22dda5 100644
--- a/aiohttp_swagger/__init__.py
+++ b/aiohttp_swagger/__init__.py
@@ -1,4 +1,5 @@
 import asyncio
+import re
 from os.path import abspath, dirname, join
 from types import FunctionType
 
@@ -91,12 +92,14 @@ def setup_swagger(app: web.Application,
     # --------------------------------------------------------------------------
     app["SWAGGER_DEF_CONTENT"] = swagger_info
     with open(join(STATIC_PATH, "index.html"), "r") as f:
+        SWAGGER_CONFIG_STR = '/{}{}'.format(api_base_url, _swagger_def_url)
+        SWAGGER_CONFIG_STR = re.sub(r'/+', '/', SWAGGER_CONFIG_STR)
+        STATIC_PATH_STR = '/{}{}'.format(api_base_url, statics_path)
+        STATIC_PATH_STR = re.sub(r'/+', '/', STATIC_PATH_STR)
         app["SWAGGER_TEMPLATE_CONTENT"] = (
             f.read()
-            .replace("##SWAGGER_CONFIG##", '/{}{}'.
-                     format(api_base_url.lstrip('/'), _swagger_def_url))
-            .replace("##STATIC_PATH##", '/{}{}'.
-                     format(api_base_url.lstrip('/'), statics_path))
+            .replace("##SWAGGER_CONFIG##", SWAGGER_CONFIG_STR)
+            .replace("##STATIC_PATH##", STATIC_PATH_STR)
         )
 
 
diff --git a/aiohttp_swagger/helpers/builders.py b/aiohttp_swagger/helpers/builders.py
index e8bbdc0..9e87971 100644
--- a/aiohttp_swagger/helpers/builders.py
+++ b/aiohttp_swagger/helpers/builders.py
@@ -1,3 +1,4 @@
+import inspect
 from collections import defaultdict
 from os.path import abspath, dirname, join
 
@@ -40,7 +41,7 @@ def _build_doc_from_func_doc(route):
 
     out = {}
 
-    if issubclass(route.handler, web.View) and route.method == METH_ANY:
+    if inspect.isclass(route.handler) and issubclass(route.handler, web.View) and route.method == METH_ANY:
         method_names = {
             attr for attr in dir(route.handler) \
             if attr.upper() in METH_ALL
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 3cd18a0..28314a4 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,5 +1,6 @@
 -r requirements.txt
-pytest
+pytest~=4.3.0
+attrs~=18.2.0
 pytest-cov
 pytest-aiohttp
 flake8
\ No newline at end of file
diff --git a/setup.py b/setup.py
index 4c7ca06..b59e052 100755
--- a/setup.py
+++ b/setup.py
@@ -55,7 +55,7 @@ def run(self):
 
 setup(
     name='aiohttp-swagger',
-    version='1.0.5',
+    version='1.0.6',
     install_requires=required,
     url='https://github.com/cr0hn/aiohttp-swagger',
     license='BSD',