Removed one more utils reference in the README and fixed directory name

Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>

tests/notifications_utils/test_url_safe_tokens.py

@@ -0,0 +1,36 @@
+import urllib
+
+from itsdangerous import BadSignature, SignatureExpired
+from pytest import fail
+
+from notifications_utils.url_safe_token import check_token, generate_token
+
+
+def test_should_return_payload_from_signed_token():
+    payload = "email@something.com"
+    token = generate_token(payload, "secret-key", "dangerous-salt")
+    token = urllib.parse.unquote(token)
+    assert payload == check_token(token, "secret-key", "dangerous-salt", 30)
+
+
+def test_should_throw_exception_when_token_is_tampered_with():
+    import uuid
+
+    token = generate_token(str(uuid.uuid4()), "secret-key", "dangerous-salt")
+    try:
+        check_token(token + "qerqwer", "secret-key", "dangerous-salt", 30)
+        fail()
+    except BadSignature:
+        pass
+
+
+def test_return_none_when_token_is_expired():
+    max_age = -1000
+    payload = "some_payload"
+    token = generate_token(payload, "secret-key", "dangerous-salt")
+    token = urllib.parse.unquote(token)
+    try:
+        assert check_token(token, "secret-key", "dangerous-salt", max_age) is None
+        fail("Expected a SignatureExpired exception")
+    except SignatureExpired:
+        pass