This library defines fixtures, resources used in test cases that are automatically created and destroyed at the beginning and end of each test case. Fixtures are built on top of rackunit test cases and the disposable library; familiarity with the two is assumed in this document.
(define-fixture tmpdir (disposable-directory)) (define-fixture tmpfile (disposable-file)) (test-case/fixture "tests" #:fixture tmpdir #:fixture tmpfile (test-case "some-test" ... use (current-tmpdir) and (current-tmpfile) ...) (test-case "other-test" ... use different (current-tmpdir) and (current-tmpfile) ...))
Warning! This library is experimental; it may change in backwards incompatible ways without notice. As such, now is the best time for feedback and suggestions so feel free to open a repository issue or reach out to me directly.
This package provides several modules, all in the fixture collection:
|(require fixture/base)||package: fixture|
A fixture is an external resource that must be properly initialized and disposed of for a test. Fixtures are essentially a pair of a disposable defining the external resource and a parameter that is set for each test to an instance of the disposable.
Additionally, fixtures may have fixture info; custom metadata about the current value of the fixture that can be used in test failure messages. Each fixture defines what info values it provides and there are no restrictions on the kind of values a fixture may use for info, although it’s expected that calling write on them produces something relatively useful.
> (define (example-info n) (format "example value of ~v" n))
> (define ex (fixture 'ex example-disposable #:info-proc example-info))
> (call/fixture ex (thunk (displayln (fixture-value ex)) (displayln (fixture-info ex))))
example value of 66
> (fixture-value ex)
fixture-value: contract violation
in: an and/c case of
the 1st argument of
(and/c fixture? fixture-initialized?)
contract from: <pkgs>/fixture/base.rkt
(assuming the contract is correct)
(define-fixture id disposable-expr fixture-option ...)
fixture-option = #:accessor-id accessor-id | #:info-proc info-proc-expr
disposable-expr : disposable?
info-proc-expr : (-> any/c any/c)
> (define (example-info n) (format "example value of ~v" n)) > (define-fixture ex example-disposable #:info-proc example-info)
> (call/fixture ex (thunk (displayln (current-ex)) (displayln (fixture-info ex))))
example value of 42
raise-argument-error: contract violation
argument position: 3rd
"fixture not initialized"
> (define-fixture ex example-disposable) > (call/fixture ex (thunk (* (current-ex) (current-ex))))
> (struct example-info (value) #:transparent) > (define-fixture ex example-disposable #:info-proc example-info) > (call/fixture ex (thunk (fixture-info ex)))
|(require fixture/rackunit)||package: fixture|
(test-begin/fixture fixture-clause ... body ...+)
fixture-clause = #:fixture fixture-expr
fixture-expr : fixture?
> (define-fixture ex1 example-disposable) > (define-fixture ex2 example-disposable) > (define (ex-sum) (+ (current-ex1) (current-ex2)))
> (test-begin/fixture #:fixture ex1 #:fixture ex2 (displayln (ex-sum)) (test-case "nested" (displayln (ex-sum))))
Additionally, test failures are augmented with a check-info with the name 'fixtures. The info’s value is a nested-info containing one check info for each fixture used; that info’s name and value correspond to the fixture’s name and its fixture info at the time the test failure occurred.
> (define-fixture file1 (disposable-file)) > (define-fixture file2 (disposable-file))
> (test-begin/fixture #:fixture file1 #:fixture file2 (check-equal? 1 2))
(test-case/fixture name fixture-clause ... body ...+)
name = string-literal fixture-clause = #:fixture fixture-expr
fixture-expr : fixture?