diff --git a/tests/default.nix b/tests/default.nix
index 525f4d4..9ef374a 100644
--- a/tests/default.nix
+++ b/tests/default.nix
@@ -73,7 +73,7 @@ in
   fastapi-utils = callTest ./fastapi-utils { };
   awscli = callTest ./awscli { };
   aiopath = callTest ./aiopath { };
-  # BROKEN fetched-projectdir = callTest ./fetched-projectdir { };
+  fetched-projectdir = callTest ./fetched-projectdir { };
   assorted-pkgs = callTest ./assorted-pkgs { };
   watchfiles = callTest ./watchfiles { };
   sqlalchemy = callTest ./sqlalchemy { };
diff --git a/tests/fetched-projectdir/default.nix b/tests/fetched-projectdir/default.nix
index db543e2..a719fe5 100644
--- a/tests/fetched-projectdir/default.nix
+++ b/tests/fetched-projectdir/default.nix
@@ -1,11 +1,23 @@
-{ poetry2nix, python39, fetchFromGitHub }:
+{ pkgs, poetry2nix, python39, fetchFromGitHub }:
 
-poetry2nix.mkPoetryApplication {
-  projectDir = fetchFromGitHub {
+let
+  rawProjectDir = fetchFromGitHub {
     owner = "nix-community";
     repo = "pynixutil";
     rev = "d27d778dc9109227b927ab88fedb2e3c2d6a7265";
     sha256 = "sha256-+Ey384Nz6hvDZAA5OYO0EAGkGjY9Kz4134CRIMjEeyg=";
   };
+  # patch the project dir to use poetry-core instead of poetry
+  projectDir = pkgs.runCommand "pyproject-dir" { } ''
+    mkdir -p $out
+    cp -r ${rawProjectDir}/* $out
+    sed \
+      -i $out/pyproject.toml \
+      -e 's/poetry>=0\.12/poetry-core/g' \
+      -e 's/poetry\.masonry/poetry.core.masonry/g'
+  '';
+in
+poetry2nix.mkPoetryApplication {
+  inherit projectDir;
   python = python39;
 }