whitelist on exact match

test/fun_core/basic_signup_whitelist_test.exs

@@ -1,11 +1,15 @@
 defmodule FunCore.BasicSignupWhitelistTest do
   use ExUnit.Case
 
-  def mail_whitelisted_fun(_signups_allowed, _email_received) do
+  def mail_whitelisted_fun(signups_allowed, email_received) do
-    false
+    signups_allowed == email_received
   end
 
   test "When not set, not whitelisted" do
     refute(mail_whitelisted_fun(nil, "joe@example.com"))
   end
+
+  test "When set and mach, then whitelisted" do
+    assert(mail_whitelisted_fun("joe@example.com", "joe@example.com"))
+  end
 end