Standardize read return value name in tests
Standardize read return value name in tests

Call it promise, rather than result, since we use result to refer to the
data itself in other places.

Signed-off-by: Kevin Locke <ffb4761cba839470133bee36aeb139f58d7dbaa9@kevinlocke.name>

kevinoid/promised-read,kevinoid/promised-read,kevinoid/promised-read