diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index 5c0be39e..55c1f6f3 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -18,6 +18,7 @@ our @ISA = qw(Exporter);
 our @EXPORT = qw(
     cancelBuilds
     captureStdoutStderr
+    captureStdoutStderrWithStdin
     findLog
     gcRootFor
     getBaseUrl
@@ -428,14 +429,19 @@ sub pathIsInsidePrefix {
 
 sub captureStdoutStderr {
     my ($timeout, @cmd) = @_;
-    my $stdin = "";
+
+    return captureStdoutStderrWithStdin($timeout, \@cmd, "");
+}
+
+sub captureStdoutStderrWithStdin {
+    my ($timeout, $cmd, $stdin) = @_;
     my $stdout;
     my $stderr;
 
     eval {
         local $SIG{ALRM} = sub { die "timeout\n" }; # NB: \n required
         alarm $timeout;
-        IPC::Run::run(\@cmd, \$stdin, \$stdout, \$stderr);
+        IPC::Run::run($cmd, \$stdin, \$stdout, \$stderr);
         alarm 0;
         1;
     } or do {
diff --git a/t/lib/CliRunners.pm b/t/lib/CliRunners.pm
index e693eeb7..ddaa34ae 100644
--- a/t/lib/CliRunners.pm
+++ b/t/lib/CliRunners.pm
@@ -5,6 +5,7 @@ package CliRunners;
 our @ISA = qw(Exporter);
 our @EXPORT = qw(
     captureStdoutStderr
+    captureStdoutStderrWithStdin
     evalFails
     evalSucceeds
     runBuild
@@ -21,6 +22,15 @@ sub captureStdoutStderr {
     return Hydra::Helper::Nix::captureStdoutStderr(@_)
 }
 
+sub captureStdoutStderrWithStdin {
+    # "Lazy"-load Hydra::Helper::Nix to avoid the compile-time
+    # import of Hydra::Model::DB. Early loading of the DB class
+    # causes fixation of the DSN, and we need to fixate it after
+    # the temporary DB is setup.
+    require Hydra::Helper::Nix;
+    return Hydra::Helper::Nix::captureStdoutStderrWithStdin(@_)
+}
+
 sub evalSucceeds {
     my ($jobset) = @_;
     my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-eval-jobset", $jobset->project->name, $jobset->name));
diff --git a/t/lib/Setup.pm b/t/lib/Setup.pm
index d7772731..56e01bdc 100644
--- a/t/lib/Setup.pm
+++ b/t/lib/Setup.pm
@@ -13,6 +13,7 @@ use CliRunners;
 our @ISA = qw(Exporter);
 our @EXPORT = qw(
     captureStdoutStderr
+    captureStdoutStderrWithStdin
     createBaseJobset
     createJobsetWithOneInput
     evalFails