diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index cba34cc4..958da4d1 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -393,7 +393,7 @@ sub captureStdoutStderr {
 
     if ($@) {
         die unless $@ eq "timeout\n"; # propagate unexpected errors
-        return (-1, "", "timeout\n");
+        return (-1, $stdout, ($stderr // "") . "timeout\n");
     } else {
         return ($?, $stdout, $stderr);
     }
diff --git a/tests/Setup.pm b/tests/Setup.pm
index 209d950d..9985cca2 100644
--- a/tests/Setup.pm
+++ b/tests/Setup.pm
@@ -72,6 +72,10 @@ sub evalSucceeds {
 sub runBuild {
     my ($build) = @_;
     my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-queue-runner", "-vvvv", "--build-one", $build->id));
+    if ($res) {
+        print STDERR "Queue runner stdout: $stdout\n" if $stdout ne "";
+        print STDERR "Queue runner stderr: $stderr\n" if $stderr ne "";
+    }
     return !$res;
 }