diff --git a/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/default.nix b/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/default.nix
index 3715e2e840d26..7b0df23ee6639 100644
--- a/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/default.nix
+++ b/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/default.nix
@@ -6,12 +6,9 @@ let
     val = 1;
   };
 
-  include_file = (writeText "libconfig-test-include" ''
+  include_file = writeText "libconfig-test-include" ''
     val=1;
-  '').overrideAttrs {
-    outputHashAlgo = "sha256";
-    outputHashMode = "flat";
-  };
+  '';
 
   expression = {
     simple_top_level_attr = "1.0";
@@ -63,12 +60,15 @@ in
 
     doCheck = true;
     checkPhase = ''
-      diff -U3 ${./expected.txt} ${libconfig-test-cfg}
+      cp ${./expected.txt} expected.txt
+      substituteInPlace expected.txt \
+          --subst-var-by include_file "${include_file}"
+      diff -U3 ./expected.txt ${libconfig-test-cfg}
     '';
 
     installPhase = ''
       mkdir $out
-      cp ${./expected.txt} $out/expected.txt
+      cp expected.txt $out
       cp ${libconfig-test-cfg} $out/libconfig-test.cfg
       cp ${libconfig-test-cfg.passthru.json} $out/libconfig-test.json
     '';
diff --git a/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/expected.txt b/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/expected.txt
index 3e9b1af821f18..ef6e09f8111a4 100644
--- a/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/expected.txt
+++ b/pkgs/pkgs-lib/formats/libconfig/test/comprehensive/expected.txt
@@ -1,6 +1,6 @@
 array1d=[1, 5, 2];array2d=([1, 2], [2, 1]);list1d=(1, "mixed!", 5, 2);list2d=(1, (1, 1.2, "foo"), ("bar", 1.2, 1));nasty_string="\"@
 \\	^*bf
 0\";'''$";nested={attrset={has={a={integer={value=100;};};};};};simple_top_level_attr="1.0";some_floaty=29.95;weirderTypes={
-@include "/nix/store/jdz5yhzbbj4j77yrr7l20x1cs4kbwkj2-libconfig-test-include"
+@include "@include_file@"
 array_of_ints=[0732, 0xa3, 1234];bigint=9223372036854775807;float=0.0012;hex=0x1fc3;list_of_weird_types=(3.141592654, 9223372036854775807, 0x1fc3, 027, 1.2e-32, 1.0);octal=027;pi=3.141592654;};