gnu: Add python-doc8.

* gnu/packages/python-xyz.scm (python-doc8): New variable.

gnu/packages/python-xyz.scm

@@ -3244,6 +3244,45 @@ reStructuredText.")
 format.")
     (license license:unlicense)))
 
+(define-public python-doc8
+  (package
+    (name "python-doc8")
+    (version "0.8.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "doc8" version))
+       (sha256
+        (base32
+         "0hw5w8mpgsp51qg8nnq28p7y1jiksvz7a0axnn5bkgss3af9zy1d"))))
+    (build-system python-build-system)
+    (arguments
+     `(#:phases
+       (modify-phases %standard-phases
+         (delete 'check)
+         (add-after 'install 'check
+           (lambda* (#:key inputs outputs tests? #:allow-other-keys)
+             (when tests?
+               (add-installed-pythonpath inputs outputs)
+               (invoke "pytest" "-v"))
+             #t)))))
+    (propagated-inputs
+     `(("python-chardet" ,python-chardet)
+       ("python-docutils" ,python-docutils)
+       ("python-restructuredtext-lint" ,python-restructuredtext-lint)
+       ("python-six" ,python-six)
+       ("python-stevedore" ,python-stevedore)))
+    (native-inputs
+     `(("python-testtools" ,python-testtools)
+       ("python-pytest" ,python-pytest)))
+    (home-page "https://launchpad.net/doc8")
+    (synopsis
+     "Style checker for Sphinx (or other) RST documentation")
+    (description
+     "Doc8 is an opinionated style checker for reStructured Text and plain
+text styles of documentation.")
+    (license license:asl2.0)))
+
 (define-public python-pygments
   (package
     (name "python-pygments")