diff --git a/.gitignore b/.gitignore
index 34a6b66..15c9ea8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *egg-info
 __pycache__
 *cookies.txt
+.tox/
diff --git a/humblebundle_downloader/download_library.py b/humblebundle_downloader/download_library.py
index a2aa21d..33dee61 100644
--- a/humblebundle_downloader/download_library.py
+++ b/humblebundle_downloader/download_library.py
@@ -37,7 +37,6 @@ class DownloadLibrary:
             platform_include = []
         self.platform_include = list(map(str.lower, platform_include))
 
-        self.cache_file = os.path.join(library_path, '.cache.json')
         self.purchase_keys = purchase_keys
         self.trove = trove
         self.update = update
@@ -59,6 +58,7 @@ class DownloadLibrary:
 
     def start(self):
 
+        self.cache_file = os.path.join(self.library_path, '.cache.json')
         self.cache_data = self._load_cache_data(self.cache_file)
         self.purchase_keys = self.purchase_keys if self.purchase_keys else self._get_purchase_keys()  # noqa: E501
 
diff --git a/tests/test_download_library.py b/tests/test_download_library.py
index a2ad0cc..f3d473d 100644
--- a/tests/test_download_library.py
+++ b/tests/test_download_library.py
@@ -6,7 +6,6 @@ from humblebundle_downloader.download_library import DownloadLibrary
 ###
 def test_include_logic_has_values():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         ext_include=['pdf', 'EPub'],
     )
@@ -18,7 +17,6 @@ def test_include_logic_has_values():
 
 def test_include_logic_empty():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         ext_include=[],
     )
@@ -30,7 +28,6 @@ def test_include_logic_empty():
 
 def test_exclude_logic_has_values():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         ext_exclude=['pdf', 'EPub'],
     )
@@ -42,7 +39,6 @@ def test_exclude_logic_has_values():
 
 def test_exclude_logic_empty():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         ext_exclude=[],
     )
@@ -57,7 +53,6 @@ def test_exclude_logic_empty():
 ###
 def test_download_platform_filter_none():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         platform_include=None,
     )
@@ -67,7 +62,6 @@ def test_download_platform_filter_none():
 
 def test_download_platform_filter_blank():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         platform_include=[],
     )
@@ -77,7 +71,6 @@ def test_download_platform_filter_blank():
 
 def test_download_platform_filter_audio():
     dl = DownloadLibrary(
-        'fake_cookie_path',
         'fake_library_path',
         platform_include=['audio'],
     )
diff --git a/tox.ini b/tox.ini
index 5eb97ad..f9ce213 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,10 @@
 [tox]
-envlist = flake8
+envlist = flake8, py36
 
+[testenv]
+deps =
+    pytest
+commands = pytest
 
 [testenv:flake8]
 basepython = python3