diff --git a/pkgs/test/texlive/default.nix b/pkgs/test/texlive/default.nix
index caeca4ae00c6..2444334f5268 100644
--- a/pkgs/test/texlive/default.nix
+++ b/pkgs/test/texlive/default.nix
@@ -152,4 +152,16 @@
         | tee "$out/scheme-infraonly/$fname.patch"
     done
   '';
+
+  # test that fmtutil.cnf is fully regenerated on scheme-full
+  fmtutilCnf = runCommandNoCC "texlive-test-fmtutil.cnf" {
+    kpathsea = lib.head texlive.kpathsea.pkgs;
+    schemeFull = texlive.combined.scheme-full;
+  } ''
+    mkdir -p "$out"
+
+    diff --ignore-matching-lines='^# Generated by ' -u \
+      {"$kpathsea","$schemeFull"/share/texmf}/web2c/fmtutil.cnf \
+      | tee "$out/fmtutil.cnf.patch"
+  '';
 }