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package matchers_test
import (
"errors"
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
. "github.com/onsi/gomega/matchers"
)
var _ = Describe("WithTransformMatcher", func() {
var plus1 = func(i int) int { return i + 1 }
Context("Panic if transform function invalid", func() {
panicsWithTransformer := func(transform interface{}) {
ExpectWithOffset(1, func() { WithTransform(transform, nil) }).To(Panic())
}
It("nil", func() {
panicsWithTransformer(nil)
})
Context("Invalid number of args, but correct return value count", func() {
It("zero", func() {
panicsWithTransformer(func() int { return 5 })
})
It("two", func() {
panicsWithTransformer(func(i, j int) int { return 5 })
})
})
Context("Invalid number of return values, but correct number of arguments", func() {
It("zero", func() {
panicsWithTransformer(func(i int) {})
})
It("two", func() {
panicsWithTransformer(func(i int) (int, int) { return 5, 6 })
})
})
})
It("works with positive cases", func() {
Expect(1).To(WithTransform(plus1, Equal(2)))
Expect(1).To(WithTransform(plus1, WithTransform(plus1, Equal(3))))
Expect(1).To(WithTransform(plus1, And(Equal(2), BeNumerically(">", 1))))
// transform expects custom type
type S struct {
A int
B string
}
transformer := func(s S) string { return s.B }
Expect(S{1, "hi"}).To(WithTransform(transformer, Equal("hi")))
// transform expects interface
errString := func(e error) string { return e.Error() }
Expect(errors.New("abc")).To(WithTransform(errString, Equal("abc")))
})
It("works with negative cases", func() {
Expect(1).ToNot(WithTransform(plus1, Equal(3)))
Expect(1).ToNot(WithTransform(plus1, WithTransform(plus1, Equal(2))))
})
Context("failure messages", func() {
Context("when match fails", func() {
It("gives a descriptive message", func() {
m := WithTransform(plus1, Equal(3))
Expect(m.Match(1)).To(BeFalse())
Expect(m.FailureMessage(1)).To(Equal("Expected\n <int>: 2\nto equal\n <int>: 3"))
})
})
Context("when match succeeds, but expected it to fail", func() {
It("gives a descriptive message", func() {
m := Not(WithTransform(plus1, Equal(3)))
Expect(m.Match(2)).To(BeFalse())
Expect(m.FailureMessage(2)).To(Equal("Expected\n <int>: 3\nnot to equal\n <int>: 3"))
})
})
Context("actual value is incompatible with transform function's argument type", func() {
It("gracefully fails if transform cannot be performed", func() {
m := WithTransform(plus1, Equal(3))
result, err := m.Match("hi") // give it a string but transform expects int; doesn't panic
Expect(result).To(BeFalse())
Expect(err).To(MatchError("Transform function expects 'int' but we have 'string'"))
})
})
})
Context("MatchMayChangeInTheFuture()", func() {
It("Propagates value from wrapped matcher on the transformed value", func() {
m := WithTransform(plus1, Or()) // empty Or() always returns false, and indicates it cannot change
Expect(m.Match(1)).To(BeFalse())
Expect(m.(*WithTransformMatcher).MatchMayChangeInTheFuture(1)).To(BeFalse()) // empty Or() indicates cannot change
})
It("Defaults to true", func() {
m := WithTransform(plus1, Equal(2)) // Equal does not have this method
Expect(m.Match(1)).To(BeTrue())
Expect(m.(*WithTransformMatcher).MatchMayChangeInTheFuture(1)).To(BeTrue()) // defaults to true
})
})
})
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