gnu: Add python-asynctest.

* gnu/packages/python-xyz.scm (python-asynctest): New variable.

gnu/packages/python-xyz.scm

@@ -18867,6 +18867,35 @@ (define-public python-asyncgui
 without requiring an event loop, useful for creative responsive GUIs.")
     (license license:expat)))
 
+(define-public python-asynctest
+  (package
+    (name "python-asynctest")
+    (version "0.13.0")
+    (source (origin
+              (method url-fetch)
+              (uri (pypi-uri "asynctest" version))
+              (sha256
+               (base32
+                "1b3zsy7p84gag6q8ai2ylyrhx213qdk2h2zb6im3xn0m5n264y62"))))
+    (build-system python-build-system)
+    (arguments
+     ;; The test suite appears to be incompatible with Python 3.9+, completes
+     ;; with 25 failures and 41 errors out of 220 tests (see:
+     ;; https://github.com/Martiusweb/asynctest/issues/149).
+     (list #:tests? #f
+           #:phases #~(modify-phases %standard-phases
+                        (replace 'check
+                          (lambda* (#:key tests? #:allow-other-keys)
+                            (when tests?
+                              (invoke "python" "-m" "unittest" "test")))))))
+    (home-page "https://github.com/Martiusweb/asynctest/")
+    (synopsis "Unittest extensions for testing asyncio libraries")
+    (description
+     "The @code{asynctest} Python package is built on top of the standard
+@code{unittest} module and cuts down boilerplate code when testing libraries
+for @code{asyncio}.")
+    (license license:asl2.0)))
+
 (define-public python-binaryornot
   (package
     (name "python-binaryornot")