`expect_type(..., "promise")` fails because of evaluating a promise

[ErdaradunGaztea]

(I have testthat v3.3.2 installed)

It seems that it's not possible to test for "promise" type of an object using expect_type(). I've dug down and the issue lies in quasi_label(), then labelled_value(), and finally in this line calling list(val = value, lab = label), where value is a promise that gets therefore evaluated. I have no idea how to fix it at the moment.

A reprex:

x <- environment()
delayedAssign("q", {
    message("Promise evaluated")
    1
}, assign.env = x)
testthat::expect_type(x[["q"]], "promise")
#> Promise evaluated
#> Error:
#> ! Expected `x[["q"]]` to have type "promise".
#> Actual type: "double"

^{Created on 2026-04-08 with reprex v2.1.1}

[hadley]

Right, because touching a promise always evaluates it. You'd need to use some other technique to access it. I thought substitute(q, x) would work, but I must have forgotten the details.

[ErdaradunGaztea]

That makes sense! Just for the sake of completeness (because someone might search for it one day), I've used testthat::expect_true(rlang::inherits_only(x[["q"]], "promise")) which doesn't evaluate x[["q"]] as far as I know (base inherit() should probably work as well).