diff --git a/pass.py b/auth.py
similarity index 100%
rename from pass.py
rename to auth.py
diff --git a/test_auth.py b/test_auth.py
new file mode 100644
index 0000000..b2ef1d1
--- /dev/null
+++ b/test_auth.py
@@ -0,0 +1,88 @@
+import auth
+import pathlib
+import pickle
+import tempfile
+
+# global pathname thingies
+PWDB_FLNAME = pathlib.Path('pwdb.pkl')
+pwdb_path = tempfile.gettempdir() / PWDB_FLNAME
+
+# user data that is correct
+db_right = list()
+db_right.append(('daniel', 'vargas', '=2od%]1*9Q', 9966))
+db_right.append(('nadine', 'heere', 'j=U]V.n`l\\', 10976))
+db_right.append(('mayar', 'ali', 'PJM0~RD*|&', 6986))
+db_right.append(('marc', 'vischer', 'nL*E~T&az1', 13112))
+db_right.append(('pooja', 'subramaniam', '%9<:%fSN$}', 18453))
+
+
+# user data that is incorrect
+db_wrong = list()
+db_wrong.append(('joel', 'afreth', 'c:d{<Am),Z', 11060)) # should be 11069
+
+
+# databases in the format that is used by auth
+db_dict_right = dict()
+for user in db_right:
+    db_dict_right[user[0]] = (user[3], user[2])
+
+db_dict_wrong = dict()
+for user in db_wrong:
+    db_dict_wrong[user[0]] = (user[3], user[2])
+
+## start test functions
+
+def test_get_salt():
+    salts = [auth.get_salt() for i in range(100)]
+    assert all([len(salt) == 10 for salt in salts]), 'Some are not 10 characters long'
+    assert len(set(salts)) == len(salts), 'Tested 100 salts are not unique'
+
+
+def test_pwhash():
+    for user in db_right:
+        assert auth.pwhash(user[1], user[2]) == user[3]
+
+    for user in db_wrong:
+        assert auth.pwhash(user[1], user[2]) != user[3]
+
+
+def test_authenticate():
+    for user in db_right:
+        assert auth.authenticate(user[0], user[1], db_dict_right)
+
+    for user in db_wrong:
+        assert not auth.authenticate(user[0], user[1], db_dict_wrong)
+
+
+def test_io():
+    with open(pwdb_path, 'wb+') as right_file:
+        auth.write_pwdb(db_dict_right, right_file)
+
+    with open(pwdb_path, 'rb+') as right_file:
+        assert auth.read_pwdb(right_file) == db_dict_right
+
+
+def test_add_user():
+    user = ('evert', 'de man', '6v"&?5UXx-', 10173)
+
+    with open(pwdb_path, 'wb+') as right_file:
+        auth.add_user(user[0], user[1], user[2], db_dict_right, right_file)
+
+    assert db_dict_right[user[0]] == (user[3], user[2]), 'Dict is not right in memory'
+
+    with open(pwdb_path, 'rb+') as right_file:
+        assert auth.read_pwdb(right_file) == db_dict_right
+
+
+def test_add_existing_user():
+    # get an existing user from our database
+    user = db_right[-1]
+
+    flag = False
+    with open(pwdb_path, 'wb+') as right_file:
+        try:
+            auth.add_user(user[0], user[1], user[2], db_dict_right, right_file)
+        except:
+            flag = True
+
+    assert flag