diff --git a/default.nix b/default.nix
index ac04ba9..b76381e 100644
--- a/default.nix
+++ b/default.nix
@@ -400,7 +400,8 @@ rec {
     name = "${pname}-${version}";
     src = ./.;
     propagatedBuildInputs = python_deps;
-    doCheck = false;
+    checkInputs = [ python.pkgs.pytest ];
+    checkPhase = "pytest";
   };
 
   # the main functions
diff --git a/mach_nix/nix/python-deps.nix b/mach_nix/nix/python-deps.nix
index ba29e7d..944b772 100644
--- a/mach_nix/nix/python-deps.nix
+++ b/mach_nix/nix/python-deps.nix
@@ -16,14 +16,6 @@ rec {
     };
     doCheck = false;
   };
-  toml = python.pkgs.buildPythonPackage {
-    name = "toml-0.10.1";
-    src = fetchurl {
-      url = "https://files.pythonhosted.org/packages/da/24/84d5c108e818ca294efe7c1ce237b42118643ce58a14d2462b3b2e3800d5/toml-0.10.1.tar.gz";
-      sha256 = "926b612be1e5ce0634a2ca03470f95169cf16f939018233a670519cb4ac58b0f";
-    };
-    doCheck = false;
-  };
   tree-format = python.pkgs.buildPythonPackage {
     name = "tree-format-0.1.2";
     src = fetchurl {
@@ -35,4 +27,5 @@ rec {
 
   packaging = python.pkgs.packaging;
   setuptools = python.pkgs.setuptools;
+  toml = python.pkgs.toml;
 }
diff --git a/pytest.ini b/pytest.ini
index 9ecd450..8da091f 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,4 +1,3 @@
 [pytest]
-addopts = -ra -q
 testpaths =
     mach_nix/tests