diff --git a/pkgs/build-support/writers/test.nix b/pkgs/build-support/writers/test.nix
index e39681865ab2..3b8b449d7585 100644
--- a/pkgs/build-support/writers/test.nix
+++ b/pkgs/build-support/writers/test.nix
@@ -471,7 +471,7 @@ recurseIntoAttrs {
     toml = expectDataEqual {
       file = writeTOML "data.toml" { hello = "world"; };
       expected = ''
-        hello = "world"
+        hello = 'world'
       '';
     };