diff --git a/src/requests/adapters.py b/src/requests/adapters.py
index 6d5951f251..257735179e 100644
--- a/src/requests/adapters.py
+++ b/src/requests/adapters.py
@@ -327,7 +327,7 @@ def cert_verify(self, conn, url, verify, cert):
                 if not os.path.exists(cert_loc):
                     raise OSError(
                         f"Could not find a suitable TLS CA certificate bundle, "
-                        f"invalid path: {cert_loc}"
+                        f"invalid path: {cert_loc!r}"
                     )
 
                 if not os.path.isdir(cert_loc):
@@ -349,11 +349,11 @@ def cert_verify(self, conn, url, verify, cert):
             if conn.cert_file and not os.path.exists(conn.cert_file):
                 raise OSError(
                     f"Could not find the TLS certificate file, "
-                    f"invalid path: {conn.cert_file}"
+                    f"invalid path: {conn.cert_file!r}"
                 )
             if conn.key_file and not os.path.exists(conn.key_file):
                 raise OSError(
-                    f"Could not find the TLS key file, invalid path: {conn.key_file}"
+                    f"Could not find the TLS key file, invalid path: {conn.key_file!r}"
                 )
 
     def build_response(self, req, resp):
diff --git a/tests/test_requests.py b/tests/test_requests.py
index 75d2deff2e..2f65368ad7 100644
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -960,26 +960,24 @@ def test_invalid_ca_certificate_path(self, httpbin_secure):
         INVALID_PATH = "/garbage"
         with pytest.raises(IOError) as e:
             requests.get(httpbin_secure(), verify=INVALID_PATH)
-        assert str(
-            e.value
-        ) == "Could not find a suitable TLS CA certificate bundle, invalid path: {}".format(
-            INVALID_PATH
+        assert (
+            str(e.value)
+            == f"Could not find a suitable TLS CA certificate bundle, invalid path: {INVALID_PATH!r}"
         )
 
     def test_invalid_ssl_certificate_files(self, httpbin_secure):
         INVALID_PATH = "/garbage"
         with pytest.raises(IOError) as e:
             requests.get(httpbin_secure(), cert=INVALID_PATH)
-        assert str(
-            e.value
-        ) == "Could not find the TLS certificate file, invalid path: {}".format(
-            INVALID_PATH
+        assert (
+            str(e.value)
+            == f"Could not find the TLS certificate file, invalid path: {INVALID_PATH!r}"
         )
 
         with pytest.raises(IOError) as e:
             requests.get(httpbin_secure(), cert=(".", INVALID_PATH))
         assert str(e.value) == (
-            f"Could not find the TLS key file, invalid path: {INVALID_PATH}"
+            f"Could not find the TLS key file, invalid path: {INVALID_PATH!r}"
         )
 
     @pytest.mark.parametrize(
@@ -2460,7 +2458,6 @@ def test_expires_none(self):
 
 
 class TestMorselToCookieMaxAge:
-
     """Tests for morsel_to_cookie when morsel contains max-age."""
 
     def test_max_age_valid_int(self):