8.12
9 Macro Expansion Expectations
procedure
(expect-expand exp [#:namespace ns]) → expectation?
exp : expectation? ns : namespace? = (current-namespace)
Returns an expectation that expects a syntax object object
stx, then a thunk that evaluates (expand stx) is created and
checked against exp. The call to expand is made with
current-namespace parameterized to ns. Combine this with
expect-raise to test that a specific syntax error is made, or combine
with expect-return to test properties of the resulting fully expanded
syntax. See also expect-syntax-exn.
Examples:
> (define success #f) > (define-syntax-rule (foo (id v) ...) success)
> (expect! #'(foo (a 1) (b 2)) (expect-expand (expect-return (expect-syntax 'success)))) > (expect! #'(foo a) (expect-expand expect-not-raise)) expected no value raised
subject: #<syntax:eval:4:0 (foo a)>
in: application to #<procedure:expand>
in: the raised value
expected: nothing
actual: (exn:fail:syntax "eval:4:0: foo: use does not
match pattern: (foo (id v) ...)\n in: (foo a)"
#<continuation-mark-set> '(#<syntax:eval:4:0 (foo a)>))
procedure
(expect-expand-once exp [#:namespace ns]) → expectation?
exp : expectation? ns : namespace? = (current-namespace)
procedure
(expect-syntax-exn [msg-exp #:namespace ns]) → expectation?
msg-exp : (or/c string? regexp? expectation?) = expect-any ns : namespace? = (current-namespace)
Returns an expectation that expects a syntax object and
expects that expanding that syntax object raises an exn:fail:syntax
value whose message is checked against msg-exp. The syntax object is
expanded with current-namespace parameterized to ns. If
msg-exp is a regexp, it is converted to an expectation with
expect-regexp-match. Otherwise, it is converted with
->expectation. This procedure is essentially sugar over combining
expect-expand, expect-raise, expect-struct, and
expect-regexp-match manually.
Example:
> (expect! #'(let ([a 1] [a 2]) (void)) (expect-syntax-exn #rx"duplicate"))