从文档：
https://godoc.org/github.com/stretchr/testify/assert#InDelta
InDelta 断言这两个数字在彼此的 delta 范围内
https://godoc.org/github.com/stretchr/testify/assert#InEpsilon
InEpsilon 断言预期和实际的相对误差小于 epsilon
他们的代码在目的上似乎是相同的：
func InDelta(t TestingT, expected, actual interface{}, delta float64, msgAndArgs ...interface{}) bool {
af, aok := toFloat(expected)
bf, bok := toFloat(actual)
if !aok || !bok {
return Fail(t, fmt.Sprintf("Parameters must be numerical"), msgAndArgs...)
}
if math.IsNaN(af) {
return Fail(t, fmt.Sprintf("Expected must not be NaN"), msgAndArgs...)
}
if math.IsNaN(bf) {
return Fail(t, fmt.Sprintf("Expected %v with delta %v, but was NaN", expected, delta), msgAndArgs...)
}
dt := af - bf
if dt < -delta || dt > delta {
return Fail(t, fmt.Sprintf("Max difference between %v and %v allowed is %v, but difference was %v", expected, actual, delta, dt), msgAndArgs...)
}
return true
}
func calcRelativeError(expected, actual interface{}) (float64, error) {
af, aok := toFloat(expected)
if !aok {
return 0, fmt.Errorf("expected value %q cannot be converted to float", expected)
}
if af == 0 {
return 0, fmt.Errorf("expected value must have a value other than zero to calculate the relative error")
}
bf, bok := toFloat(actual)
if !bok {
return 0, fmt.Errorf("actual value %q cannot be converted to float", actual)
}
return math.Abs(af-bf) / math.Abs(af), nil
}
// InEpsilon asserts that expected and actual have a relative error less than epsilon
//
// Returns whether the assertion was successful (true) or not (false).
func InEpsilon(t TestingT, expected, actual interface{}, epsilon float64, msgAndArgs ...interface{}) bool {
actualEpsilon, err := calcRelativeError(expected, actual)
if err != nil {
return Fail(t, err.Error(), msgAndArgs...)
}
if actualEpsilon > epsilon {
return Fail(t, fmt.Sprintf("Relative error is too high: %#v (expected)\n"+
" < %#v (actual)", epsilon, actualEpsilon), msgAndArgs...)
}
return true
}
有什么不同？有哪些用例可以将一个用于另一个，反之亦然？