diff --git a/src/cryptojwt/jwk/ec.py b/src/cryptojwt/jwk/ec.py
index 4acf9d9..9334922 100644
--- a/src/cryptojwt/jwk/ec.py
+++ b/src/cryptojwt/jwk/ec.py
@@ -113,7 +113,7 @@ def __init__(self, kty="EC", alg="", use="", kid="", crv="", x="", y="", d="", *
     def deserialize(self):
         """
         Starting with information gathered from the on-the-wire representation
-        of an elliptic curve key (a JWK) initiate an
+        of an elliptic curve key (a JWK) initiate a
         cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey
         or EllipticCurvePrivateKey instance. So we have to get from having::
 
diff --git a/src/cryptojwt/jws/dsa.py b/src/cryptojwt/jws/dsa.py
index 59f6604..6ddedcf 100644
--- a/src/cryptojwt/jws/dsa.py
+++ b/src/cryptojwt/jws/dsa.py
@@ -85,7 +85,7 @@ def verify(self, msg, sig, key):
     def _cross_check(self, pub_key):
         """
         In Ecdsa, both the key and the algorithm define the curve.
-        Therefore, we must cross check them to make sure they're the same.
+        Therefore, we must crosscheck them to make sure they're the same.
 
         :param key:
         :raises: ValueError is the curves are not the same
diff --git a/src/cryptojwt/key_bundle.py b/src/cryptojwt/key_bundle.py
index 0fde736..0708d0e 100755
--- a/src/cryptojwt/key_bundle.py
+++ b/src/cryptojwt/key_bundle.py
@@ -235,7 +235,7 @@ def __init__(
 
         :param keys: A dictionary or a list of dictionaries
             with the keys ["kty", "key", "alg", "use", "kid"]
-        :param source: Where the key set can be fetch from
+        :param source: Where the key set can be fetched from
         :param fileformat: For a local file either "jwks" or "der"
         :param keytype: Iff local file and 'der' format what kind of key it is.
             presently 'rsa' and 'ec' are supported.
@@ -467,7 +467,7 @@ def _do_remote(self, set_keys=True):
 
         if self.ignore_errors_until and time.time() < self.ignore_errors_until:
             LOGGER.warning(
-                "Not reading remote JWKS from %s (in error holddown until %s)",
+                "Not reading remote JWKS from %s (in error hold down until %s)",
                 self.source,
                 datetime.fromtimestamp(self.ignore_errors_until),
             )
diff --git a/src/cryptojwt/key_issuer.py b/src/cryptojwt/key_issuer.py
index 1151edc..08e540a 100755
--- a/src/cryptojwt/key_issuer.py
+++ b/src/cryptojwt/key_issuer.py
@@ -91,7 +91,7 @@ def add_url(self, url, **kwargs):
         if not url:
             raise KeyError("No url given")
 
-        logger.debug("httpc_params: %s", self.httpc_params)
+        logger.debug(f"add_url: httpc_params: {self.httpc_params}")
 
         if "/localhost:" in url or "/localhost/" in url:
             _params = self.httpc_params.copy()
@@ -433,7 +433,7 @@ def mark_all_keys_as_inactive(self):
 
         self._bundles = kbl
 
-    def key_summary(self):
+    def key_summary(self) -> str:
         """
         Return a text representation of all the keys.
 
diff --git a/src/cryptojwt/key_jar.py b/src/cryptojwt/key_jar.py
index f3716b0..2bec768 100755
--- a/src/cryptojwt/key_jar.py
+++ b/src/cryptojwt/key_jar.py
@@ -324,10 +324,10 @@ def load_keys(self, issuer_id, jwks_uri="", jwks=None, replace=False):
         :param jwks: A dictionary representation of a JWKS
         :param issuer_id: The provider URL
         :param replace: If all previously gathered keys from this provider
-            should be replace.
+            should be replaced.
         :return: Dictionary with usage as key and keys as values
         """
-        logger.debug("Initiating key bundle for issuer: %s" % issuer_id)
+        logger.debug(f"Initiating key bundle for issuer: {issuer_id}")
 
         _issuer = self.return_issuer(issuer_id)
         if replace:
diff --git a/src/cryptojwt/simple_jwt.py b/src/cryptojwt/simple_jwt.py
index c0ec92f..fbdaf2b 100644
--- a/src/cryptojwt/simple_jwt.py
+++ b/src/cryptojwt/simple_jwt.py
@@ -75,7 +75,7 @@ def pack(self, parts=None, headers=None):
             else:
                 headers = {"alg": "none"}
 
-        logging.debug("JWT header: {}".format(headers))
+        logging.debug("(pack) JWT header: {}".format(headers))
 
         if not parts:
             return ".".join([a.decode() for a in self.b64part])
diff --git a/tests/test_04_key_jar.py b/tests/test_04_key_jar.py
index 5f00243..c2d9d2d 100755
--- a/tests/test_04_key_jar.py
+++ b/tests/test_04_key_jar.py
@@ -853,7 +853,7 @@ def test_key_summary():
     kj.add_kb("C", KeyBundle(JWK2["keys"]))
 
     out = kj.key_summary("Alice")
-    assert out
+    assert out == "RSA::abc"
 
 
 PUBLIC_FILE = "{}/public_jwks.json".format(BASEDIR)
diff --git a/tests/test_09_jwt.py b/tests/test_09_jwt.py
index c8ec65c..452ee8c 100755
--- a/tests/test_09_jwt.py
+++ b/tests/test_09_jwt.py
@@ -244,7 +244,7 @@ class DummyMsg(object):
     def __init__(self, **kwargs):
         for key, val in kwargs.items():
             setattr(self, key, val)
-        self.jws_headers = {}
+        self.jws_header = {}
 
     def verify(self, **kwargs):
         return True
diff --git a/tests/test_40_serialize.py b/tests/test_40_serialize.py
index 4c7dbb9..f83b9f6 100644
--- a/tests/test_40_serialize.py
+++ b/tests/test_40_serialize.py
@@ -1,10 +1,6 @@
 import os
 
-from cryptojwt.jwk.hmac import SYMKey
-from cryptojwt.jwk.rsa import RSAKey
-from cryptojwt.jwk.rsa import import_rsa_key_from_cert_file
 from cryptojwt.key_bundle import keybundle_from_local_file
-from cryptojwt.key_bundle import rsa_init
 from cryptojwt.key_issuer import KeyIssuer
 from cryptojwt.serialize import item