pythonPackages.staticjinja: enable tests

and:
* fetch from github (tests on pypi get somehow disabled)
* formatting

pkgs/development/python-modules/staticjinja/default.nix

@@ -1,24 +1,45 @@
 { lib
-, fetchPypi
+, fetchFromGitHub
 , buildPythonPackage
+, isPy27
 , docopt
 , easywatch
 , jinja2
+, pytestCheckHook
+, markdown
 }:
 
 buildPythonPackage rec {
   pname = "staticjinja";
   version = "0.4.0";
 
-  src = fetchPypi {
-    inherit pname version;
-    sha256 = "597837899008409359680ee9cd04779639b9c0eb3380b6545025d26a702ba36c";
+  disabled = isPy27; # 0.4.0 drops python2 support
+
+  # For some reason, in pypi the tests get disabled when using
+  # PY_IGNORE_IMPORTMISMATCH, so we just fetch from GitHub
+  src = fetchFromGitHub {
+    owner = "staticjinja";
+    repo = pname;
+    rev = version;
+    sha256 = "0pysk8pzmcg1nfxz8m4i6bvww71w2zg6xp33zgg5vrf8yd2dfx9i";
   };
 
-  propagatedBuildInputs = [ jinja2 docopt easywatch ];
+  propagatedBuildInputs = [
+    jinja2
+    docopt
+    easywatch
+  ];
 
-  # There are no tests on pypi
-  doCheck = false;
+  checkInputs = [
+    pytestCheckHook
+    markdown
+  ];
+
+  # Import paths differ by a "build/lib" subdirectory, but the files are
+  # the same, so we ignore import mismatches.
+  preCheck = ''
+    export PY_IGNORE_IMPORTMISMATCH=1
+  '';
 
   meta = with lib; {
     description = "A library and cli tool that makes it easy to build static sites using Jinja2";
@@ -27,4 +48,3 @@ buildPythonPackage rec {
     maintainers = with maintainers; [ fgaz ];
   };
 }
-