Make another package for unit testing helpers.
diff --git a/testhelper/doc.go b/testhelper/doc.go
new file mode 100644
index 0000000..25b4dfe
--- /dev/null
+++ b/testhelper/doc.go
@@ -0,0 +1,4 @@
+/*
+Package testhelper container methods that are useful for writing unit tests.
+*/
+package testhelper