diff --git a/gaurun/worker_test.go b/gaurun/worker_test.go
new file mode 100644
index 0000000..f7c35d7
--- /dev/null
+++ b/gaurun/worker_test.go
@@ -0,0 +1,35 @@
+package gaurun
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/RobotsAndPencils/buford/push"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsExternalServerError(t *testing.T) {
+	cases := []struct {
+		Err      error
+		Platform int
+		Expected bool
+	}{
+		{push.ErrIdleTimeout, PlatFormIos, true},
+		{push.ErrShutdown, PlatFormIos, true},
+		{push.ErrInternalServerError, PlatFormIos, true},
+		{push.ErrServiceUnavailable, PlatFormIos, true},
+		{errors.New("no error"), PlatFormIos, false},
+
+		{errors.New("Unavailable"), PlatFormAndroid, true},
+		{errors.New("InternalServerError"), PlatFormAndroid, true},
+		{errors.New("Timeout"), PlatFormAndroid, true},
+		{errors.New("no error"), PlatFormAndroid, false},
+
+		{errors.New("no error"), 100 /* neither iOS nor Android */, false},
+	}
+
+	for _, c := range cases {
+		actual := isExternalServerError(c.Err, c.Platform)
+		assert.Equal(t, actual, c.Expected)
+	}
+}