diff --git a/src/lib/Hydra/Controller/JobsetEval.pm b/src/lib/Hydra/Controller/JobsetEval.pm
index ed0fe12e..17b14ae1 100644
--- a/src/lib/Hydra/Controller/JobsetEval.pm
+++ b/src/lib/Hydra/Controller/JobsetEval.pm
@@ -6,6 +6,7 @@ use warnings;
 use base 'Hydra::Base::Controller::NixChannel';
 use Hydra::Helper::Nix;
 use Hydra::Helper::CatalystUtils;
+use Hydra::Helper::BuildDiff;
 use List::SomeUtils qw(uniq);
 
 
@@ -75,55 +76,7 @@ sub view_GET {
     @builds  = sort { cmpBuilds($a, $b) } @builds;
     @builds2 = sort { cmpBuilds($a, $b) } @builds2;
 
-    $c->stash->{stillSucceed} = [];
-    $c->stash->{stillFail} = [];
-    $c->stash->{nowSucceed} = [];
-    $c->stash->{nowFail} = [];
-    $c->stash->{new} = [];
-    $c->stash->{removed} = [];
-    $c->stash->{unfinished} = [];
-    $c->stash->{aborted} = [];
-    $c->stash->{failed} = [];
-
-    my $n = 0;
-    foreach my $build (@builds) {
-        my $aborted = $build->finished != 0 && ($build->buildstatus == 3 || $build->buildstatus == 4);
-        my $d;
-        my $found = 0;
-        while ($n < scalar(@builds2)) {
-            my $build2 = $builds2[$n];
-            my $d = cmpBuilds($build, $build2);
-            last if $d == -1;
-            if ($d == 0) {
-                $n++;
-                $found = 1;
-                if ($aborted) {
-                    # do nothing
-                } elsif ($build->finished == 0 || $build2->finished == 0) {
-                    push @{$c->stash->{unfinished}}, $build;
-                } elsif ($build->buildstatus == 0 && $build2->buildstatus == 0) {
-                    push @{$c->stash->{stillSucceed}}, $build;
-                } elsif ($build->buildstatus != 0 && $build2->buildstatus != 0) {
-                    push @{$c->stash->{stillFail}}, $build;
-                } elsif ($build->buildstatus == 0 && $build2->buildstatus != 0) {
-                    push @{$c->stash->{nowSucceed}}, $build;
-                } elsif ($build->buildstatus != 0 && $build2->buildstatus == 0) {
-                    push @{$c->stash->{nowFail}}, $build;
-                } else { die; }
-                last;
-            }
-            push @{$c->stash->{removed}}, { job => $build2->get_column('job'), system => $build2->get_column('system') };
-            $n++;
-        }
-        if ($aborted) {
-            push @{$c->stash->{aborted}}, $build;
-        } else {
-            push @{$c->stash->{new}}, $build if !$found;
-        }
-        if ($build->buildstatus != 0) {
-            push @{$c->stash->{failed}}, $build;
-        }
-    }
+    buildDiff(@builds, @builds2);
 
     $c->stash->{full} = ($c->req->params->{full} || "0") eq "1";
 
diff --git a/src/lib/Hydra/Helper/BuildDiff.pm b/src/lib/Hydra/Helper/BuildDiff.pm
new file mode 100644
index 00000000..7655bf4d
--- /dev/null
+++ b/src/lib/Hydra/Helper/BuildDiff.pm
@@ -0,0 +1,76 @@
+package Hydra::Helper::BuildDiff;
+
+use utf8;
+use strict;
+use warnings;
+use base 'Hydra::Base::Controller::NixChannel';
+use Hydra::Helper::Nix;
+use Hydra::Helper::CatalystUtils;
+use List::SomeUtils qw(uniq);
+
+our @ISA = qw(Exporter);
+our @EXPORT = qw(
+    buildDiff
+);
+
+use Data::Dumper;
+
+sub buildDiff {
+    my ($builds, $builds2) = @_;
+
+    my $ret = [
+        stillSucceed => [],
+        stillFail => [],
+        nowSucceed => [],
+        nowFail => [],
+        new => [],
+        removed => [],
+        unfinished => [],
+        aborted => [],
+        failed => [],
+    ];
+
+    my $n = 0;
+    foreach my $build (@{$builds}) {
+        my $aborted = $build->finished != 0 && ($build->buildstatus == 3 || $build->buildstatus == 4);
+        my $d;
+        my $found = 0;
+        while ($n < scalar($builds2)) {
+            my $build2 = @{$builds2}[$n];
+            my $d = cmpBuilds($build, $build2);
+            last if $d == -1;
+            if ($d == 0) {
+                $n++;
+                $found = 1;
+                if ($aborted) {
+                    # do nothing
+                } elsif ($build->finished == 0 || $build2->finished == 0) {
+                    push @{$ret->{unfinished}}, $build;
+                } elsif ($build->buildstatus == 0 && $build2->buildstatus == 0) {
+                    push @{$ret->{stillSucceed}}, $build;
+                } elsif ($build->buildstatus != 0 && $build2->buildstatus != 0) {
+                    push @{$ret->{stillFail}}, $build;
+                } elsif ($build->buildstatus == 0 && $build2->buildstatus != 0) {
+                    push @{$ret->{nowSucceed}}, $build;
+                } elsif ($build->buildstatus != 0 && $build2->buildstatus == 0) {
+                    push @{$ret->{nowFail}}, $build;
+                } else { die; }
+                last;
+            }
+            push @{$ret->{removed}}, { job => $build2->get_column('job'), system => $build2->get_column('system') };
+            $n++;
+        }
+        if ($aborted) {
+            push @{$ret->{aborted}}, $build;
+        } else {
+            push @{$ret->{new}}, $build if !$found;
+        }
+        if ($build->buildstatus != 0) {
+            push @{$ret->{failed}}, $build;
+        }
+    }
+
+    return $ret;
+}
+
+1;
\ No newline at end of file