73 lines
2.3 KiB
Go
73 lines
2.3 KiB
Go
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package matchers
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import (
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"fmt"
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"reflect"
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"github.com/onsi/gomega/internal/oraclematcher"
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"github.com/onsi/gomega/types"
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)
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type WithTransformMatcher struct {
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// input
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Transform interface{} // must be a function of one parameter that returns one value
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Matcher types.GomegaMatcher
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// cached value
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transformArgType reflect.Type
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// state
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transformedValue interface{}
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}
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func NewWithTransformMatcher(transform interface{}, matcher types.GomegaMatcher) *WithTransformMatcher {
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if transform == nil {
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panic("transform function cannot be nil")
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}
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txType := reflect.TypeOf(transform)
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if txType.NumIn() != 1 {
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panic("transform function must have 1 argument")
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}
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if txType.NumOut() != 1 {
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panic("transform function must have 1 return value")
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}
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return &WithTransformMatcher{
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Transform: transform,
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Matcher: matcher,
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transformArgType: reflect.TypeOf(transform).In(0),
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}
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}
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func (m *WithTransformMatcher) Match(actual interface{}) (bool, error) {
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// return error if actual's type is incompatible with Transform function's argument type
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actualType := reflect.TypeOf(actual)
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if !actualType.AssignableTo(m.transformArgType) {
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return false, fmt.Errorf("Transform function expects '%s' but we have '%s'", m.transformArgType, actualType)
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}
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// call the Transform function with `actual`
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fn := reflect.ValueOf(m.Transform)
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result := fn.Call([]reflect.Value{reflect.ValueOf(actual)})
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m.transformedValue = result[0].Interface() // expect exactly one value
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return m.Matcher.Match(m.transformedValue)
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}
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func (m *WithTransformMatcher) FailureMessage(_ interface{}) (message string) {
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return m.Matcher.FailureMessage(m.transformedValue)
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}
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func (m *WithTransformMatcher) NegatedFailureMessage(_ interface{}) (message string) {
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return m.Matcher.NegatedFailureMessage(m.transformedValue)
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}
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func (m *WithTransformMatcher) MatchMayChangeInTheFuture(_ interface{}) bool {
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// TODO: Maybe this should always just return true? (Only an issue for non-deterministic transformers.)
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//
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// Querying the next matcher is fine if the transformer always will return the same value.
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// But if the transformer is non-deterministic and returns a different value each time, then there
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// is no point in querying the next matcher, since it can only comment on the last transformed value.
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return oraclematcher.MatchMayChangeInTheFuture(m.Matcher, m.transformedValue)
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}
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