pythonPackages.pytest-django: unpin setuptools_scm

- unpin setuptools_scm
- move to file in folder following guidelines
- use PyPI/upstream name

pkgs/development/python-modules/pytest-django/default.nix

@@ -0,0 +1,33 @@
+{ stdenv, buildPythonPackage, fetchurl
+, pytest, django, setuptools_scm
+, fetchpatch
+}:
+buildPythonPackage rec {
+  name = "pytest-django-${version}";
+  version = "3.1.2";
+
+  src = fetchurl {
+    url = "mirror://pypi/p/pytest-django/${name}.tar.gz";
+    sha256 = "02932m2sr8x22m4az8syr8g835g4ak77varrnw71n6xakmdcr303";
+  };
+
+  buildInputs = [ pytest setuptools_scm ];
+  propagatedBuildInputs = [ django ];
+
+  patches = [
+    # Unpin setuptools-scm
+    (fetchpatch {
+      url = "https://github.com/pytest-dev/pytest-django/commit/25cbc3b395dcdeb92bdc9414e296680c2b9d602e.patch";
+      sha256 = "1mx06y4kz2zs41mb2h9bh5p4jc6s6hfsq6fghhsks5b7qak05xjp";
+    })
+  ];
+
+  # Complicated. Requires Django setup.
+  doCheck = false;
+
+  meta = with stdenv.lib; {
+    description = "py.test plugin for testing of Django applications";
+    homepage = http://pytest-django.readthedocs.org/en/latest/;
+    license = licenses.bsd3;
+  };
+}