diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..5ab8eaf
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,3 @@
+[run]
+include =
+    marvelous/*
diff --git a/docs/index.rst b/docs/index.rst
index 12fb630..dd8b4ba 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -70,25 +70,24 @@ Instantiating API
 
     public_key = "Public key from https://developer.marvel.com/account"
     private_key = "Private key from https://developer.marvel.com/account"
-    print_calls = True  # Will print URL of app API calls, for debugging
 
-    def CacheClass:
-      def get(self, key):
-        # This method should return cahed value with key
-        return None
+    # Optional
+    class CacheClass:
+        def get(self, key):
+            # This method should return cahed value with key
+            return None
 
-      def store(self, key, value):
-        # This method should store key value pair
-        return
+        def store(self, key, value):
+            # This method should store key value pair
+            return
 
     cache = CacheClass()
 
     # m is a session object, read about it below
     m = marvelous.api(
-      public_key,
-      private_key,
-      print_calls=print_calls,
-      cache=cache
+        public_key,
+        private_key,
+        cache=cache
     )
 
 
@@ -187,7 +186,7 @@ Series
 - ``response`` - Dictionary, raw response body
 - ``id`` - Int
 - ``resource_uri`` - String, `resourceURI` from API
-- ``name`` - String
+- ``title`` - String
 - ``comics`` - Method, Returns ``ComicsList`` object for `/v1/public/series/{seriesId}/comics`
 
 
diff --git a/marvelous/comic.py b/marvelous/comic.py
index 9d7ec12..07d29c3 100644
--- a/marvelous/comic.py
+++ b/marvelous/comic.py
@@ -47,7 +47,7 @@ def process_input(self, data):
         # Marvel comic 1768, and maybe others, returns a modified of
         # "-0001-11-30T00:00:00-0500". The best way to handle this is
         # probably just to ignore it, since I don't know how to fix it.
-        if new_data['modified'][0] == '-':
+        if new_data.get('modified', ' ')[0] == '-':
             del new_data['modified']
 
         return new_data
diff --git a/marvelous/comics_list.py b/marvelous/comics_list.py
index dd15f5e..562612f 100644
--- a/marvelous/comics_list.py
+++ b/marvelous/comics_list.py
@@ -19,6 +19,9 @@ def __init__(self, response):
     def __iter__(self):
         return iter(self.comics)
 
+    def __len__(self):
+        return len(self.comics)
+
     def __getitem__(self, index):
         try:
             return next(itertools.islice(self.comics, index, index+1))
diff --git a/marvelous/series.py b/marvelous/series.py
index 74edb15..176684a 100644
--- a/marvelous/series.py
+++ b/marvelous/series.py
@@ -1,9 +1,9 @@
 from marshmallow import Schema, fields, pre_load, post_load
 
-from . import comics_list
+from . import comics_list, exceptions
 
 
-class Series():
+class Series:
     def __init__(self, **kwargs):
         if 'response' not in kwargs:
             kwargs['response'] = None
@@ -11,7 +11,10 @@ def __init__(self, **kwargs):
         for k, v in kwargs.items():
             setattr(self, k, v)
 
-    def comics(self, params):
+    def comics(self, params=None):
+        if params is None:
+            params = {}
+
         return comics_list.ComicsList(
             self.session.call(['series', self.id, 'comics'], params=params))
 
@@ -20,10 +23,13 @@ class SeriesSchema(Schema):
     response = fields.Raw()
     id = fields.Int()
     resourceURI = fields.Str(attribute='resource_uri')
-    name = fields.Str()
+    title = fields.Str()
 
     @pre_load
     def process_input(self, data):
+        if data.get('code', 200) != 200:
+            raise exceptions.ApiError(data.get('status'))
+
         if 'status' in data:
             data['data']['results'][0]['response'] = data
             data = data['data']['results'][0]
diff --git a/marvelous/session.py b/marvelous/session.py
index 23c375b..601834b 100644
--- a/marvelous/session.py
+++ b/marvelous/session.py
@@ -8,13 +8,10 @@
 class Session():
     api_url = "http://gateway.marvel.com:80/v1/public/{}"
 
-    def __init__(
-            self, public_key, private_key, cache=None,
-            print_calls=False):
+    def __init__(self, public_key, private_key, cache=None):
 
         self.public_key = public_key
         self.private_key = private_key
-        self.print_calls = print_calls
         self.cache = cache
 
     def call(self, endpoint, params=None):
@@ -46,13 +43,10 @@ def call(self, endpoint, params=None):
 
         response = requests.get(url, params=params)
 
-        if self.print_calls:
-            print(response.url)
-
         data = response.json()
 
         if 'message' in data:
-            raise exceptions.ApiError(response['message'])
+            raise exceptions.ApiError(data['message'])
 
         if self.cache and response.status_code == 200:
             try:
diff --git a/tests/cache_test.py b/tests/cache_test.py
new file mode 100644
index 0000000..a968130
--- /dev/null
+++ b/tests/cache_test.py
@@ -0,0 +1,42 @@
+import os
+import unittest
+
+import marvelous
+
+
+class NoGet:
+    def store(self, key, value):
+        # This method should store key value pair
+        return
+
+
+class NoStore:
+    def get(self, key):
+        # This method should return cahed value with key
+        return None
+
+
+class TestComics(unittest.TestCase):
+    def setUp(self):
+        self.pub = os.getenv('PUBLIC_KEY', 'pub')
+        self.priv = os.getenv('PRIVATE_KEY', 'priv')
+
+    def test_no_get(self):
+        m = marvelous.api(
+            public_key=self.pub, private_key=self.priv,
+            cache=NoGet())
+
+        with self.assertRaises(marvelous.exceptions.CacheError):
+            m.series(466)
+
+    def test_no_store(self):
+        m = marvelous.api(
+            public_key=self.pub, private_key=self.priv,
+            cache=NoStore())
+
+        with self.assertRaises(marvelous.exceptions.CacheError):
+            m.series(466)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/tests/series_test.py b/tests/series_test.py
new file mode 100644
index 0000000..3a7dd7b
--- /dev/null
+++ b/tests/series_test.py
@@ -0,0 +1,35 @@
+import os
+import unittest
+
+import marvelous
+from marvelous.comics_list import ComicsList
+
+
+class TestComics(unittest.TestCase):
+    def setUp(self):
+        pub = os.getenv('PUBLIC_KEY', 'pub')
+        priv = os.getenv('PRIVATE_KEY', 'priv')
+        self.m = marvelous.api(
+            public_key=pub, private_key=priv,
+            cache=marvelous.SqliteCache("tests/testing_mock.sqlite"))
+
+    def test_known_series(self):
+        usms = self.m.series(466)
+        self.assertTrue(usms.title == "Ultimate Spider-Man (2000 - 2009)")
+        self.assertTrue(usms.id == 466)
+        comics = usms.comics()
+        self.assertTrue(comics[0].id == 23931)
+
+        self.assertTrue(len(comics[:5]) == 5)
+        self.assertTrue(len(comics) == len([x for x in comics if x.id > 3]))
+
+    def test_bad_series(self):
+        with self.assertRaises(marvelous.exceptions.ApiError):
+            self.m.series(-1)
+
+    def test_bad_response_data(self):
+        with self.assertRaises(marvelous.exceptions.ApiError):
+            ComicsList({'data': {'results': [{'modified': 'potato'}]}})
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/tests/testing_mock.sqlite b/tests/testing_mock.sqlite
index aab3d18..84afbe5 100644
Binary files a/tests/testing_mock.sqlite and b/tests/testing_mock.sqlite differ