test-doubles.md
... ...
@@ -65,6 +65,8 @@ specific converters we are going to want, or have one in hand.
65 65
66 66
A stub is an implementation that returns a canned answer (POODR, p. 210).
67 67
68
+**NOTE:** We stub on the DOC, not on the SUT. For some guidance on this, see <https://robots.thoughtbot.com/don-t-stub-the-system-under-test>.
69
+
68 70
If we create a stub manually, we will want an instance of FToCConverter's convert method to return
69 71
a value that we can verify. It might look like this:
70 72