diff --git a/nix/pytest-circular-import/.gitignore b/nix/pytest-circular-import/.gitignore
new file mode 100644
index 0000000..bee8a64
--- /dev/null
+++ b/nix/pytest-circular-import/.gitignore
@@ -0,0 +1 @@
+__pycache__
diff --git a/nix/pytest-circular-import/default.nix b/nix/pytest-circular-import/default.nix
new file mode 100644
index 0000000..2ba3fdc
--- /dev/null
+++ b/nix/pytest-circular-import/default.nix
@@ -0,0 +1,2 @@
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.python3Packages.callPackage ./package.nix { }
diff --git a/nix/pytest-circular-import/demo_cython_pytest/__init__.py b/nix/pytest-circular-import/demo_cython_pytest/__init__.py
new file mode 100644
index 0000000..2d78dc0
--- /dev/null
+++ b/nix/pytest-circular-import/demo_cython_pytest/__init__.py
@@ -0,0 +1 @@
+from .module import native_sum
diff --git a/nix/pytest-circular-import/demo_cython_pytest/module.py b/nix/pytest-circular-import/demo_cython_pytest/module.py
new file mode 100644
index 0000000..e69de29
diff --git a/nix/pytest-circular-import/demo_cython_pytest/module.pyx b/nix/pytest-circular-import/demo_cython_pytest/module.pyx
new file mode 100644
index 0000000..04ad023
--- /dev/null
+++ b/nix/pytest-circular-import/demo_cython_pytest/module.pyx
@@ -0,0 +1,9 @@
+#cython: language_level=3
+
+cimport cython
+
+def native_sum(x, y):
+    return cy_sum(x, y)
+
+cdef int cy_sum(int x, int y):
+    return x + y
diff --git a/nix/pytest-circular-import/demo_cython_pytest/module_test.py b/nix/pytest-circular-import/demo_cython_pytest/module_test.py
new file mode 100644
index 0000000..6a3f48f
--- /dev/null
+++ b/nix/pytest-circular-import/demo_cython_pytest/module_test.py
@@ -0,0 +1,4 @@
+from demo_cython_pytest import native_sum
+
+def test_module():
+    assert native_sum(2, 2) == 4
diff --git a/nix/pytest-circular-import/package.nix b/nix/pytest-circular-import/package.nix
new file mode 100644
index 0000000..eb0a733
--- /dev/null
+++ b/nix/pytest-circular-import/package.nix
@@ -0,0 +1,19 @@
+{ buildPythonPackage
+, pytestCheckHook
+, cython
+, python
+}:
+
+buildPythonPackage {
+  pname = "demo_cython_pytest";
+  version = "0.0.1";
+
+  src = ./.;
+
+  pythonImportsCheck = [ "demo_cython_pytest.module.native_sum" ];
+
+  nativeBuildInputs = [
+    # pytestCheckHook
+    cython
+  ];
+}
diff --git a/nix/pytest-circular-import/setup.py b/nix/pytest-circular-import/setup.py
new file mode 100644
index 0000000..2f430c3
--- /dev/null
+++ b/nix/pytest-circular-import/setup.py
@@ -0,0 +1,31 @@
+from distutils.core import Extension
+from setuptools import setup, find_packages
+from Cython.Build import cythonize
+from Cython.Distutils import build_ext
+# from distutils.command.build_ext import build_ext
+
+
+def ext_modules():
+    modules = []
+    includes = []
+    libraries = []
+    modules += cythonize(Extension(
+        "*",
+        ["demo_cython_pytest/module.pyx"],
+        include_dirs=includes,
+        libraries=libraries
+    ))
+    return modules
+
+setup(
+    name="demo_cython_pytest",
+    version="0.0.1",
+    description="Circular imports?",
+    author="lucasew",
+    packages=["demo_cython_pytest"],
+    ext_modules=ext_modules(),
+    include_package_data=True,
+    cmdclass=dict(
+        build_ext=build_ext
+    )
+)
diff --git a/nix/pytest-circular-import/shell.nix b/nix/pytest-circular-import/shell.nix
new file mode 100644
index 0000000..90c1125
--- /dev/null
+++ b/nix/pytest-circular-import/shell.nix
@@ -0,0 +1,6 @@
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.mkShell {
+  buildInputs = [
+    (pkgs.python3Packages.callPackage ./package.nix { })
+  ];
+}