31 lines
1.2 KiB
Racket
31 lines
1.2 KiB
Racket
#lang typed/racket
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(require typed/rackunit)
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;; Test that (member v lst is-equal?) always passes v as the first argument to
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;; is-equal? . If this is not the case, the type for the is-equal? argument
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;; should be (→ (U a b) (U a b) Any) instead of (→ b a Any).
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(let ([needle : Integer
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;; Use a random needle to prevent some optimizations (but not all)
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(floor (inexact->exact (* (random) 200)))])
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(member needle
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(range 1000)
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(λ ([x : Integer] [y : Integer])
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;; Check the needle is always the first argument
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(check-equal? x needle)
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;; Check y = needle implies x = needle
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(check-true (or (not (= y needle)) (= x needle)))
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(= x y))))
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;; Test that the third is-equal? argument is taken into account. If it is taken
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;; into account, it will return '("c" "ddd" "x"). If it isn't, it will return
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;; '("x") instead.
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(check-equal? (member "x"
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'("bb" "c" "ddd" "x")
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(lambda ([s1 : String] [s2 : String])
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(= (string-length s1) (string-length s2))))
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'("c" "ddd" "x"))
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(check-equal? (member "x" '("bb" "c" "ddd" "x")) '("x"))
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