diff --git a/overlays.nix b/overlays.nix
index 17905cc72d4060155b2939711d88947f13d6735c..837bb9082beeb17515b924f26b5bd043c9e26e8a 100644
--- a/overlays.nix
+++ b/overlays.nix
@@ -16,9 +16,7 @@ self: super: {
       attrs = python-super.callPackage ./attrs.nix { };
 
       # The newer hypothesis or attrs breaks the pytest test suite.
-      pytest = python-super.pytest.overrideAttrs (old: {
-        doInstallCheck = false;
-      });
+      pytest = python-super.callPackage ./pytest.nix { };
 
       # new tahoe-lafs dependency
       eliot = python-super.callPackage ./eliot.nix { };
diff --git a/pytest.nix b/pytest.nix
new file mode 100644
index 0000000000000000000000000000000000000000..d9634ea0762acff5c9d7fdb6ebaa139538776780
--- /dev/null
+++ b/pytest.nix
@@ -0,0 +1,53 @@
+{ stdenv, buildPythonPackage, pythonOlder, fetchPypi, attrs, hypothesis, py
+, setuptools_scm, setuptools, six, pluggy, funcsigs, isPy3k, more-itertools
+, atomicwrites, mock, writeText, pathlib2, wcwidth, packaging, isPyPy, python
+}:
+buildPythonPackage rec {
+  version = "5.2.1";
+  pname = "pytest";
+
+  disabled = !isPy3k;
+
+  preCheck = ''
+    # don't test bash builtins
+    rm testing/test_argcomplete.py
+  '';
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "3805d095f1ea279b9870c3eeae5dddf8a81b10952c8835cd628cf1875b0ef032";
+  };
+
+  checkInputs = [ hypothesis mock ];
+  nativeBuildInputs = [ setuptools_scm ];
+  propagatedBuildInputs = [ attrs py setuptools six pluggy more-itertools atomicwrites wcwidth packaging ]
+    ++ stdenv.lib.optionals (pythonOlder "3.6") [ pathlib2 ];
+
+  doCheck = !isPyPy; # https://github.com/pytest-dev/pytest/issues/3460
+
+  # Ignored file https://github.com/pytest-dev/pytest/pull/5605#issuecomment-522243929
+  checkPhase = ''
+    runHook preCheck
+    $out/bin/py.test -x testing/ -k "not test_collect_pyargs_with_testpaths" --ignore=testing/test_junitxml.py
+    runHook postCheck
+  '';
+
+  # Remove .pytest_cache when using py.test in a Nix build
+  setupHook = writeText "pytest-hook" ''
+    pytestcachePhase() {
+        find $out -name .pytest_cache -type d -exec rm -rf {} +
+    }
+    preDistPhases+=" pytestcachePhase"
+  '';
+
+  pythonImportsCheck = [
+    "pytest"
+  ];
+
+  meta = with stdenv.lib; {
+    homepage = https://docs.pytest.org;
+    description = "Framework for writing tests";
+    maintainers = with maintainers; [ domenkozar lovek323 madjar lsix ];
+    license = licenses.mit;
+  };
+}