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