diff --git a/t/test.pl b/t/test.pl
index 7f17f107..ba7f3781 100644
--- a/t/test.pl
+++ b/t/test.pl
@@ -16,7 +16,7 @@ use List::SomeUtils qw(none);
 if (defined($ENV{"NIX_BUILD_CORES"})
     and not defined($ENV{"YATH_JOB_COUNT"})
     and not defined($ENV{"T2_HARNESS_JOB_COUNT"})
-    and not defined($ENV{"T2_HARNESS_JOB_COUNT"})) {
+    and not defined($ENV{"HARNESS_JOB_COUNT"})) {
     $ENV{"YATH_JOB_COUNT"} = $ENV{"NIX_BUILD_CORES"};
     print STDERR "test.pl: Defaulting \$YATH_JOB_COUNT to \$NIX_BUILD_CORES (${\$ENV{'NIX_BUILD_CORES'}})\n";
 }