diff --git a/gnu/packages/serialization.scm b/gnu/packages/serialization.scm
index 3ddb669a75..f7e5d3ca3f 100644
--- a/gnu/packages/serialization.scm
+++ b/gnu/packages/serialization.scm
@@ -706,43 +706,48 @@ RPC system.  Think JSON, except binary.  Or think Protocol Buffers, except faste
   (package
     (name "python-msgspec")
     (version "0.20.0")
-    (source (origin
-              ;; There are no tests in the PyPI tarball.
-              (method git-fetch)
-              (uri (git-reference
-                    (url "https://github.com/jcrist/msgspec")
-                    (commit version)))
-              (file-name (git-file-name name version))
-              (modules '((guix build utils)))
-              (snippet
-               ;; Delete autogenerated file, regenerate in a phase.
-               #~(begin
-                   (delete-file "src/msgspec/atof_consts.h")
-                   ;; https://github.com/jcrist/msgspec/pull/981
-                   (substitute* "scripts/generate_atof_consts.py"
-                     (("os.path.join\\(repo, " all)
-                      (string-append all "\"src\", ")))))
-              (sha256
-               (base32
-                "1nbaqdyn71zcqj3wj33xw90spm9s93c7qmfkjwbnmmx85ffycq0d"))))
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+              (url "https://github.com/jcrist/msgspec")
+              (commit version)))
+       (file-name (git-file-name name version))
+       (modules '((guix build utils)))
+       (snippet
+        #~(begin
+            ;; Delete autogenerated file, regenerate in a phase.
+            (delete-file "src/msgspec/atof_consts.h")
+            ;; See: <https://github.com/jcrist/msgspec/pull/981>.
+            (substitute* "scripts/generate_atof_consts.py"
+              (("os.path.join\\(repo, " all)
+               (string-append all "\"src\", ")))))
+       (sha256
+        (base32 "1nbaqdyn71zcqj3wj33xw90spm9s93c7qmfkjwbnmmx85ffycq0d"))))
     (build-system pyproject-build-system)
     (arguments
      (list
+      #:test-flags
       ;; .pytest.toml declares testpaths = ["tests/unit", "tests/typing"]
       ;; so --ignore=tests/typing will not work.
-      #:test-flags #~(list "tests/unit")
-      #:phases #~(modify-phases %standard-phases
-                   (add-after 'unpack 'atof-consts
-                     (lambda _
-                       (with-directory-excursion "scripts"
-                         ;; Regenerate the autogenerated file.
-                         (invoke "python" "generate_atof_consts.py")))))))
-    (native-inputs (list python-attrs
-                         python-msgpack
-                         python-pytest
-                         python-setuptools
-                         python-setuptools-scm))
-    (propagated-inputs (list python-pyyaml python-tomli python-tomli-w))
+      #~(list "tests/unit")
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'unpack 'atof-consts
+            (lambda _
+              (with-directory-excursion "scripts"
+                ;; Regenerate the autogenerated file.
+                (invoke "python" "generate_atof_consts.py")))))))
+    (native-inputs
+     (list python-attrs
+           python-msgpack
+           python-pytest
+           python-setuptools
+           python-setuptools-scm))
+    (propagated-inputs
+     (list python-pyyaml
+           python-tomli
+           python-tomli-w))
     (home-page "https://jcristharif.com/msgspec/")
     (synopsis "Fast serialization/validation library")
     (description "@code{msgspec} is a fast serialization and validation