In a vignette, put a call to change_state() before any code block that makes a change on the server, or rather, before any code block that might repeat the same request previously done and expect a different result.



Invisibly, the return of .mockPaths() with the new path added.


change_state() works by layering a new directory on top of the existing .mockPaths(), so fixtures are recorded/loaded there, masking rather than overwriting previously recorded responses for the same request. In vignettes, these mock layers are subdirectories with integer names.