--- /dev/null
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package cmpopts provides common options for the cmp package.
+package cmpopts
+
+import (
+ "math"
+ "reflect"
+ "time"
+
+ "github.com/google/go-cmp/cmp"
+ "golang.org/x/xerrors"
+)
+
+func equateAlways(_, _ interface{}) bool { return true }
+
+// EquateEmpty returns a Comparer option that determines all maps and slices
+// with a length of zero to be equal, regardless of whether they are nil.
+//
+// EquateEmpty can be used in conjunction with SortSlices and SortMaps.
+func EquateEmpty() cmp.Option {
+ return cmp.FilterValues(isEmpty, cmp.Comparer(equateAlways))
+}
+
+func isEmpty(x, y interface{}) bool {
+ vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+ return (x != nil && y != nil && vx.Type() == vy.Type()) &&
+ (vx.Kind() == reflect.Slice || vx.Kind() == reflect.Map) &&
+ (vx.Len() == 0 && vy.Len() == 0)
+}
+
+// EquateApprox returns a Comparer option that determines float32 or float64
+// values to be equal if they are within a relative fraction or absolute margin.
+// This option is not used when either x or y is NaN or infinite.
+//
+// The fraction determines that the difference of two values must be within the
+// smaller fraction of the two values, while the margin determines that the two
+// values must be within some absolute margin.
+// To express only a fraction or only a margin, use 0 for the other parameter.
+// The fraction and margin must be non-negative.
+//
+// The mathematical expression used is equivalent to:
+// |x-y| ≤ max(fraction*min(|x|, |y|), margin)
+//
+// EquateApprox can be used in conjunction with EquateNaNs.
+func EquateApprox(fraction, margin float64) cmp.Option {
+ if margin < 0 || fraction < 0 || math.IsNaN(margin) || math.IsNaN(fraction) {
+ panic("margin or fraction must be a non-negative number")
+ }
+ a := approximator{fraction, margin}
+ return cmp.Options{
+ cmp.FilterValues(areRealF64s, cmp.Comparer(a.compareF64)),
+ cmp.FilterValues(areRealF32s, cmp.Comparer(a.compareF32)),
+ }
+}
+
+type approximator struct{ frac, marg float64 }
+
+func areRealF64s(x, y float64) bool {
+ return !math.IsNaN(x) && !math.IsNaN(y) && !math.IsInf(x, 0) && !math.IsInf(y, 0)
+}
+func areRealF32s(x, y float32) bool {
+ return areRealF64s(float64(x), float64(y))
+}
+func (a approximator) compareF64(x, y float64) bool {
+ relMarg := a.frac * math.Min(math.Abs(x), math.Abs(y))
+ return math.Abs(x-y) <= math.Max(a.marg, relMarg)
+}
+func (a approximator) compareF32(x, y float32) bool {
+ return a.compareF64(float64(x), float64(y))
+}
+
+// EquateNaNs returns a Comparer option that determines float32 and float64
+// NaN values to be equal.
+//
+// EquateNaNs can be used in conjunction with EquateApprox.
+func EquateNaNs() cmp.Option {
+ return cmp.Options{
+ cmp.FilterValues(areNaNsF64s, cmp.Comparer(equateAlways)),
+ cmp.FilterValues(areNaNsF32s, cmp.Comparer(equateAlways)),
+ }
+}
+
+func areNaNsF64s(x, y float64) bool {
+ return math.IsNaN(x) && math.IsNaN(y)
+}
+func areNaNsF32s(x, y float32) bool {
+ return areNaNsF64s(float64(x), float64(y))
+}
+
+// EquateApproxTime returns a Comparer option that determines two non-zero
+// time.Time values to be equal if they are within some margin of one another.
+// If both times have a monotonic clock reading, then the monotonic time
+// difference will be used. The margin must be non-negative.
+func EquateApproxTime(margin time.Duration) cmp.Option {
+ if margin < 0 {
+ panic("margin must be a non-negative number")
+ }
+ a := timeApproximator{margin}
+ return cmp.FilterValues(areNonZeroTimes, cmp.Comparer(a.compare))
+}
+
+func areNonZeroTimes(x, y time.Time) bool {
+ return !x.IsZero() && !y.IsZero()
+}
+
+type timeApproximator struct {
+ margin time.Duration
+}
+
+func (a timeApproximator) compare(x, y time.Time) bool {
+ // Avoid subtracting times to avoid overflow when the
+ // difference is larger than the largest representible duration.
+ if x.After(y) {
+ // Ensure x is always before y
+ x, y = y, x
+ }
+ // We're within the margin if x+margin >= y.
+ // Note: time.Time doesn't have AfterOrEqual method hence the negation.
+ return !x.Add(a.margin).Before(y)
+}
+
+// AnyError is an error that matches any non-nil error.
+var AnyError anyError
+
+type anyError struct{}
+
+func (anyError) Error() string { return "any error" }
+func (anyError) Is(err error) bool { return err != nil }
+
+// EquateErrors returns a Comparer option that determines errors to be equal
+// if errors.Is reports them to match. The AnyError error can be used to
+// match any non-nil error.
+func EquateErrors() cmp.Option {
+ return cmp.FilterValues(areConcreteErrors, cmp.Comparer(compareErrors))
+}
+
+// areConcreteErrors reports whether x and y are types that implement error.
+// The input types are deliberately of the interface{} type rather than the
+// error type so that we can handle situations where the current type is an
+// interface{}, but the underlying concrete types both happen to implement
+// the error interface.
+func areConcreteErrors(x, y interface{}) bool {
+ _, ok1 := x.(error)
+ _, ok2 := y.(error)
+ return ok1 && ok2
+}
+
+func compareErrors(x, y interface{}) bool {
+ xe := x.(error)
+ ye := y.(error)
+ // TODO(≥go1.13): Use standard definition of errors.Is.
+ return xerrors.Is(xe, ye) || xerrors.Is(ye, xe)
+}
projects / dotfiles / .git / blobdiff