diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 11ff65b..20a4aac 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,19 +13,18 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: cachix/install-nix-action@v15
+      - uses: cachix/install-nix-action@v30
+      - uses: DeterminateSystems/magic-nix-cache-action@main
       - name: Run linting
         run: nix develop -c make lint-ci
   tests:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: install dependencies
-        run: python3 -m pip install --user --upgrade poetry
-      - name: install
-        run: poetry install
+      - uses: cachix/install-nix-action@v30
+      - uses: DeterminateSystems/magic-nix-cache-action@main
       - name: Run tests
-        run: make test
+        run: nix develop -c python -mpytest -vv -s
   nix-flake:
     runs-on: ubuntu-latest
     steps:
diff --git a/flake.nix b/flake.nix
index 86a3693..9b42444 100644
--- a/flake.nix
+++ b/flake.nix
@@ -8,17 +8,27 @@
       inputs.flake-utils.follows = "flake-utils";
     };
   };
-  outputs = { self, nixpkgs, flake-utils, poetry2nix }:
-    (flake-utils.lib.eachDefaultSystem (system:
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+      poetry2nix,
+    }:
+    (flake-utils.lib.eachDefaultSystem (
+      system:
       let
-        pkgs = (import nixpkgs {
-          inherit system;
-          config = { };
-          overlays = [
-            poetry2nix.overlays.default
-          ];
-        });
-        overrides = pkgs.poetry2nix.overrides.withDefaults (self: super:
+        pkgs = (
+          import nixpkgs {
+            inherit system;
+            config = { };
+            overlays = [
+              poetry2nix.overlays.default
+            ];
+          }
+        );
+        overrides = pkgs.poetry2nix.overrides.withDefaults (
+          self: super:
           let
             buildSystems = {
               durations = [ "setuptools" ];
@@ -26,23 +36,25 @@
               pytest-github-actions-annotate-failures = [ "setuptools" ];
               flake8-black = [ "setuptools" ];
               flake8-isort = [ "hatchling" ];
-              docker = [ "hatchling" "hatch-vcs" ];
+              docker = [
+                "hatchling"
+                "hatch-vcs"
+              ];
             };
           in
-          pkgs.lib.mapAttrs
-            (attr: systems: super.${attr}.overridePythonAttrs
-              (old: {
-                nativeBuildInputs = (old.nativeBuildInputs or [ ]) ++ map (a: self.${a}) systems;
-              }))
-            buildSystems
+          pkgs.lib.mapAttrs (
+            attr: systems:
+            super.${attr}.overridePythonAttrs (old: {
+              nativeBuildInputs = (old.nativeBuildInputs or [ ]) ++ map (a: self.${a}) systems;
+            })
+          ) buildSystems
         );
       in
       rec {
-        packages.default = pkgs.poetry2nix.mkPoetryApplication
-          {
-            projectDir = ./.;
-            inherit overrides;
-          };
+        packages.default = pkgs.poetry2nix.mkPoetryApplication {
+          projectDir = ./.;
+          inherit overrides;
+        };
         apps.default = {
           type = "app";
           program = "${packages.default}/bin/pystarport";
@@ -53,6 +65,12 @@
               projectDir = ./.;
               inherit overrides;
             })
+            (pkgs.poetry2nix.mkPoetryEditablePackage {
+              projectDir = ./.;
+              editablePackageSources = {
+                pystarport = ./pystarport;
+              };
+            })
           ];
         };
       }
diff --git a/pystarport/tests/test_expansion/test_expansion.py b/pystarport/tests/test_expansion/test_expansion.py
index 0abd2aa..93b8398 100644
--- a/pystarport/tests/test_expansion/test_expansion.py
+++ b/pystarport/tests/test_expansion/test_expansion.py
@@ -53,8 +53,10 @@ def test_expansion(type, func):
         }
     }
 
+    path = Path(__file__).parent
+
     # overriding dotenv with absolute path is expanded and has diff
-    dotenv = os.path.abspath("test_expansion/dotenv1")
+    dotenv = os.path.abspath(path / "dotenv1")
     config = func(cronos_has_dotenv, dotenv)
     assert DeepDiff(
         base_config,
@@ -72,7 +74,7 @@ def test_expansion(type, func):
     }
 
     # overriding dotenv with absolute path is expanded and no diff
-    dotenv = os.path.abspath("test_expansion/dotenv")
+    dotenv = os.path.abspath(path / "dotenv")
     config = func(cronos_has_posix_no_dotenv, dotenv)
     assert not DeepDiff(
         base_config,