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
}
InEpsilon asserts that expected and actual have a relative error less than epsilon

Returns whether the assertion was successful (true) or not (false).
package assert
import (
	"bufio"
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"math"
	"reflect"
	"regexp"
	"runtime"
	"strings"
	"time"
	"unicode"
	"unicode/utf8"
	"github.com/davecgh/go-spew/spew"
	"github.com/pmezard/go-difflib/difflib"
)
type TestingT interface {
	Errorf(format string, args ...interface{})
}
type Comparison func() (success bool)
func ObjectsAreEqual(expected, actual interface{}) bool {
	if expected == nil || actual == nil {
		return expected == actual
	}
	if exp, ok := expected.([]byte); ok {
		act, ok := actual.([]byte)
		if !ok {
			return false
		} else if exp == nil || act == nil {
			return exp == nil && act == nil
		}
		return bytes.Equal(exp, act)
	}
	return reflect.DeepEqual(expected, actual)
}
func ObjectsAreEqualValues(expected, actual interface{}) bool {
	if ObjectsAreEqual(expected, actual) {
		return true
	}
	actualType := reflect.TypeOf(actual)
	if actualType == nil {
		return false
	}
	expectedValue := reflect.ValueOf(expected)
	if expectedValue.IsValid() && expectedValue.Type().ConvertibleTo(actualType) {
		return reflect.DeepEqual(expectedValue.Convert(actualType).Interface(), actual)
	}
	return false
}
func CallerInfo() []string {
	pc := uintptr(0)
	file := ""
	line := 0
	ok := false
	name := ""
	callers := []string{}
	for i := 0; ; i++ {
		pc, file, line, ok = runtime.Caller(i)
		if !ok {
			break
		}
		if file == "<autogenerated>" {
			break
		}
		f := runtime.FuncForPC(pc)
		if f == nil {
			break
		}
		name = f.Name()
		if name == "testing.tRunner" {
			break
		}
		parts := strings.Split(file, "/")
		file = parts[len(parts)-1]
		if len(parts) > 1 {
			dir := parts[len(parts)-2]
			if (dir != "assert" && dir != "mock" && dir != "require") || file == "mock_test.go" {
				callers = append(callers, fmt.Sprintf("%s:%d", file, line))
			}
		}
		segments := strings.Split(name, ".")
		name = segments[len(segments)-1]
		if isTest(name, "Test") ||
			isTest(name, "Benchmark") ||
			isTest(name, "Example") {
			break
		}
	}
	return callers
}
func isTest(name, prefix string) bool {
	if !strings.HasPrefix(name, prefix) {
		return false
	}
	if len(name) == len(prefix) {  
		return true
	}
	rune, _ := utf8.DecodeRuneInString(name[len(prefix):])
	return !unicode.IsLower(rune)
}
func getWhitespaceString() string {
	_, file, line, ok := runtime.Caller(1)
	if !ok {
		return ""
	}
	parts := strings.Split(file, "/")
	file = parts[len(parts)-1]
	return strings.Repeat(" ", len(fmt.Sprintf("%s:%d:        ", file, line)))
}
func messageFromMsgAndArgs(msgAndArgs ...interface{}) string {
	if len(msgAndArgs) == 0 || msgAndArgs == nil {
		return ""
	}
	if len(msgAndArgs) == 1 {
		return msgAndArgs[0].(string)
	}
	if len(msgAndArgs) > 1 {
		return fmt.Sprintf(msgAndArgs[0].(string), msgAndArgs[1:]...)
	}
	return ""
}
func indentMessageLines(message string, longestLabelLen int) string {
	outBuf := new(bytes.Buffer)
	for i, scanner := 0, bufio.NewScanner(strings.NewReader(message)); scanner.Scan(); i++ {
		if i != 0 {
			outBuf.WriteString("\n\r\t" + strings.Repeat(" ", longestLabelLen+1) + "\t")
		}
		outBuf.WriteString(scanner.Text())
	}
	return outBuf.String()
}
type failNower interface {
	FailNow()
}
func FailNow(t TestingT, failureMessage string, msgAndArgs ...interface{}) bool {
	Fail(t, failureMessage, msgAndArgs...)
	if t, ok := t.(failNower); ok {
		t.FailNow()
	} else {
		panic("test failed and t is missing `FailNow()`")
	}
	return false
}
func Fail(t TestingT, failureMessage string, msgAndArgs ...interface{}) bool {
	content := []labeledContent{
		{"Error Trace", strings.Join(CallerInfo(), "\n\r\t\t\t")},
		{"Error", failureMessage},
	}
	message := messageFromMsgAndArgs(msgAndArgs...)
	if len(message) > 0 {
		content = append(content, labeledContent{"Messages", message})
	}
	t.Errorf("%s", "\r"+getWhitespaceString()+labeledOutput(content...))
	return false
}
type labeledContent struct {
	label   string
	content string
}
func labeledOutput(content ...labeledContent) string {
	longestLabel := 0
	for _, v := range content {
		if len(v.label) > longestLabel {
			longestLabel = len(v.label)
		}
	}
	var output string
	for _, v := range content {
		output += "\r\t" + v.label + ":" + strings.Repeat(" ", longestLabel-len(v.label)) + "\t" + indentMessageLines(v.content, longestLabel) + "\n"
	}
	return output
}
func Implements(t TestingT, interfaceObject interface{}, object interface{}, msgAndArgs ...interface{}) bool {
	interfaceType := reflect.TypeOf(interfaceObject).Elem()
	if !reflect.TypeOf(object).Implements(interfaceType) {
		return Fail(t, fmt.Sprintf("%T must implement %v", object, interfaceType), msgAndArgs...)
	}
	return true
}
func IsType(t TestingT, expectedType interface{}, object interface{}, msgAndArgs ...interface{}) bool {
	if !ObjectsAreEqual(reflect.TypeOf(object), reflect.TypeOf(expectedType)) {
		return Fail(t, fmt.Sprintf("Object expected to be of type %v, but was %v", reflect.TypeOf(expectedType), reflect.TypeOf(object)), msgAndArgs...)
	}
	return true
}
func Equal(t TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
	if err := validateEqualArgs(expected, actual); err != nil {
		return Fail(t, fmt.Sprintf("Invalid operation: %#v == %#v (%s)",
			expected, actual, err), msgAndArgs...)
	}
	if !ObjectsAreEqual(expected, actual) {
		diff := diff(expected, actual)
		expected, actual = formatUnequalValues(expected, actual)
		return Fail(t, fmt.Sprintf("Not equal: \n"+
			"expected: %s\n"+
			"actual: %s%s", expected, actual, diff), msgAndArgs...)
	}
	return true
}
func formatUnequalValues(expected, actual interface{}) (e string, a string) {
	if reflect.TypeOf(expected) != reflect.TypeOf(actual) {
		return fmt.Sprintf("%T(%#v)", expected, expected),
			fmt.Sprintf("%T(%#v)", actual, actual)
	}
	return fmt.Sprintf("%#v", expected),
		fmt.Sprintf("%#v", actual)
}
func EqualValues(t TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
	if !ObjectsAreEqualValues(expected, actual) {
		diff := diff(expected, actual)
		expected, actual = formatUnequalValues(expected, actual)
		return Fail(t, fmt.Sprintf("Not equal: \n"+
			"expected: %s\n"+
			"actual: %s%s", expected, actual, diff), msgAndArgs...)
	}
	return true
}
func Exactly(t TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
	aType := reflect.TypeOf(expected)
	bType := reflect.TypeOf(actual)
	if aType != bType {
		return Fail(t, fmt.Sprintf("Types expected to match exactly\n\r\t%v != %v", aType, bType), msgAndArgs...)
	}
	return Equal(t, expected, actual, msgAndArgs...)
}
func NotNil(t TestingT, object interface{}, msgAndArgs ...interface{}) bool {
	if !isNil(object) {
		return true
	}
	return Fail(t, "Expected value not to be nil.", msgAndArgs...)
}
func isNil(object interface{}) bool {
	if object == nil {
		return true
	}
	value := reflect.ValueOf(object)
	kind := value.Kind()
	if kind >= reflect.Chan && kind <= reflect.Slice && value.IsNil() {
		return true
	}
	return false
}
func Nil(t TestingT, object interface{}, msgAndArgs ...interface{}) bool {
	if isNil(object) {
		return true
	}
	return Fail(t, fmt.Sprintf("Expected nil, but got: %#v", object), msgAndArgs...)
}
var numericZeros = []interface{}{
	int(0),
	int8(0),
	int16(0),
	int32(0),
	int64(0),
	uint(0),
	uint8(0),
	uint16(0),
	uint32(0),
	uint64(0),
	float32(0),
	float64(0),
}
func isEmpty(object interface{}) bool {
	if object == nil {
		return true
	} else if object == "" {
		return true
	} else if object == false {
		return true
	}
	for _, v := range numericZeros {
		if object == v {
			return true
		}
	}
	objValue := reflect.ValueOf(object)
	switch objValue.Kind() {
	case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice, reflect.String:
		{
			return (objValue.Len() == 0)
		}
	case reflect.Struct:
		switch object.(type) {
		case time.Time:
			return object.(time.Time).IsZero()
		}
	case reflect.Ptr:
		{
			if objValue.IsNil() {
				return true
			}
			switch object.(type) {
			case *time.Time:
				return object.(*time.Time).IsZero()
			default:
				return false
			}
		}
	}
	return false
}
func Empty(t TestingT, object interface{}, msgAndArgs ...interface{}) bool {
	pass := isEmpty(object)
	if !pass {
		Fail(t, fmt.Sprintf("Should be empty, but was %v", object), msgAndArgs...)
	}
	return pass
}
func NotEmpty(t TestingT, object interface{}, msgAndArgs ...interface{}) bool {
	pass := !isEmpty(object)
	if !pass {
		Fail(t, fmt.Sprintf("Should NOT be empty, but was %v", object), msgAndArgs...)
	}
	return pass
}
func getLen(x interface{}) (ok bool, length int) {
	v := reflect.ValueOf(x)
	defer func() {
		if e := recover(); e != nil {
			ok = false
		}
	}()
	return true, v.Len()
}
func Len(t TestingT, object interface{}, length int, msgAndArgs ...interface{}) bool {
	ok, l := getLen(object)
	if !ok {
		return Fail(t, fmt.Sprintf("\"%s\" could not be applied builtin len()", object), msgAndArgs...)
	}
	if l != length {
		return Fail(t, fmt.Sprintf("\"%s\" should have %d item(s), but has %d", object, length, l), msgAndArgs...)
	}
	return true
}
func True(t TestingT, value bool, msgAndArgs ...interface{}) bool {
	if value != true {
		return Fail(t, "Should be true", msgAndArgs...)
	}
	return true
}
func False(t TestingT, value bool, msgAndArgs ...interface{}) bool {
	if value != false {
		return Fail(t, "Should be false", msgAndArgs...)
	}
	return true
}
func NotEqual(t TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
	if err := validateEqualArgs(expected, actual); err != nil {
		return Fail(t, fmt.Sprintf("Invalid operation: %#v != %#v (%s)",
			expected, actual, err), msgAndArgs...)
	}
	if ObjectsAreEqual(expected, actual) {
		return Fail(t, fmt.Sprintf("Should not be: %#v\n", actual), msgAndArgs...)
	}
	return true
}
func includeElement(list interface{}, element interface{}) (ok, found bool) {
	listValue := reflect.ValueOf(list)
	elementValue := reflect.ValueOf(element)
	defer func() {
		if e := recover(); e != nil {
			ok = false
			found = false
		}
	}()
	if reflect.TypeOf(list).Kind() == reflect.String {
		return true, strings.Contains(listValue.String(), elementValue.String())
	}
	if reflect.TypeOf(list).Kind() == reflect.Map {
		mapKeys := listValue.MapKeys()
		for i := 0; i < len(mapKeys); i++ {
			if ObjectsAreEqual(mapKeys[i].Interface(), element) {
				return true, true
			}
		}
		return true, false
	}
	for i := 0; i < listValue.Len(); i++ {
		if ObjectsAreEqual(listValue.Index(i).Interface(), element) {
			return true, true
		}
	}
	return true, false
}
func Contains(t TestingT, s, contains interface{}, msgAndArgs ...interface{}) bool {
	ok, found := includeElement(s, contains)
	if !ok {
		return Fail(t, fmt.Sprintf("\"%s\" could not be applied builtin len()", s), msgAndArgs...)
	}
	if !found {
		return Fail(t, fmt.Sprintf("\"%s\" does not contain \"%s\"", s, contains), msgAndArgs...)
	}
	return true
}
func NotContains(t TestingT, s, contains interface{}, msgAndArgs ...interface{}) bool {
	ok, found := includeElement(s, contains)
	if !ok {
		return Fail(t, fmt.Sprintf("\"%s\" could not be applied builtin len()", s), msgAndArgs...)
	}
	if found {
		return Fail(t, fmt.Sprintf("\"%s\" should not contain \"%s\"", s, contains), msgAndArgs...)
	}
	return true
}
func Subset(t TestingT, list, subset interface{}, msgAndArgs ...interface{}) (ok bool) {
	if subset == nil {
		return true  
	}
	subsetValue := reflect.ValueOf(subset)
	defer func() {
		if e := recover(); e != nil {
			ok = false
		}
	}()
	listKind := reflect.TypeOf(list).Kind()
	subsetKind := reflect.TypeOf(subset).Kind()
	if listKind != reflect.Array && listKind != reflect.Slice {
		return Fail(t, fmt.Sprintf("%q has an unsupported type %s", list, listKind), msgAndArgs...)
	}
	if subsetKind != reflect.Array && subsetKind != reflect.Slice {
		return Fail(t, fmt.Sprintf("%q has an unsupported type %s", subset, subsetKind), msgAndArgs...)
	}
	for i := 0; i < subsetValue.Len(); i++ {
		element := subsetValue.Index(i).Interface()
		ok, found := includeElement(list, element)
		if !ok {
			return Fail(t, fmt.Sprintf("\"%s\" could not be applied builtin len()", list), msgAndArgs...)
		}
		if !found {
			return Fail(t, fmt.Sprintf("\"%s\" does not contain \"%s\"", list, element), msgAndArgs...)
		}
	}
	return true
}
func NotSubset(t TestingT, list, subset interface{}, msgAndArgs ...interface{}) (ok bool) {
	if subset == nil {
		return false  
	}
	subsetValue := reflect.ValueOf(subset)
	defer func() {
		if e := recover(); e != nil {
			ok = false
		}
	}()
	listKind := reflect.TypeOf(list).Kind()
	subsetKind := reflect.TypeOf(subset).Kind()
	if listKind != reflect.Array && listKind != reflect.Slice {
		return Fail(t, fmt.Sprintf("%q has an unsupported type %s", list, listKind), msgAndArgs...)
	}
	if subsetKind != reflect.Array && subsetKind != reflect.Slice {
		return Fail(t, fmt.Sprintf("%q has an unsupported type %s", subset, subsetKind), msgAndArgs...)
	}
	for i := 0; i < subsetValue.Len(); i++ {
		element := subsetValue.Index(i).Interface()
		ok, found := includeElement(list, element)
		if !ok {
			return Fail(t, fmt.Sprintf("\"%s\" could not be applied builtin len()", list), msgAndArgs...)
		}
		if !found {
			return true
		}
	}
	return Fail(t, fmt.Sprintf("%q is a subset of %q", subset, list), msgAndArgs...)
}
func Condition(t TestingT, comp Comparison, msgAndArgs ...interface{}) bool {
	result := comp()
	if !result {
		Fail(t, "Condition failed!", msgAndArgs...)
	}
	return result
}
type PanicTestFunc func()
func didPanic(f PanicTestFunc) (bool, interface{}) {
	didPanic := false
	var message interface{}
	func() {
		defer func() {
			if message = recover(); message != nil {
				didPanic = true
			}
		}()
		f()
	}()
	return didPanic, message
}
func Panics(t TestingT, f PanicTestFunc, msgAndArgs ...interface{}) bool {
	if funcDidPanic, panicValue := didPanic(f); !funcDidPanic {
		return Fail(t, fmt.Sprintf("func %#v should panic\n\r\tPanic value:\t%v", f, panicValue), msgAndArgs...)
	}
	return true
}
func PanicsWithValue(t TestingT, expected interface{}, f PanicTestFunc, msgAndArgs ...interface{}) bool {
	funcDidPanic, panicValue := didPanic(f)
	if !funcDidPanic {
		return Fail(t, fmt.Sprintf("func %#v should panic\n\r\tPanic value:\t%v", f, panicValue), msgAndArgs...)
	}
	if panicValue != expected {
		return Fail(t, fmt.Sprintf("func %#v should panic with value:\t%v\n\r\tPanic value:\t%v", f, expected, panicValue), msgAndArgs...)
	}
	return true
}
func NotPanics(t TestingT, f PanicTestFunc, msgAndArgs ...interface{}) bool {
	if funcDidPanic, panicValue := didPanic(f); funcDidPanic {
		return Fail(t, fmt.Sprintf("func %#v should not panic\n\r\tPanic value:\t%v", f, panicValue), msgAndArgs...)
	}
	return true
}
func WithinDuration(t TestingT, expected, actual time.Time, delta time.Duration, msgAndArgs ...interface{}) bool {
	dt := expected.Sub(actual)
	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 toFloat(x interface{}) (float64, bool) {
	var xf float64
	xok := true
	switch xn := x.(type) {
	case uint8:
		xf = float64(xn)
	case uint16:
		xf = float64(xn)
	case uint32:
		xf = float64(xn)
	case uint64:
		xf = float64(xn)
	case int:
		xf = float64(xn)
	case int8:
		xf = float64(xn)
	case int16:
		xf = float64(xn)
	case int32:
		xf = float64(xn)
	case int64:
		xf = float64(xn)
	case float32:
		xf = float64(xn)
	case float64:
		xf = float64(xn)
	case time.Duration:
		xf = float64(xn)
	default:
		xok = false
	}
	return xf, xok
}
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 InDeltaSlice(t TestingT, expected, actual interface{}, delta float64, msgAndArgs ...interface{}) bool {
	if expected == nil || actual == nil ||
		reflect.TypeOf(actual).Kind() != reflect.Slice ||
		reflect.TypeOf(expected).Kind() != reflect.Slice {
		return Fail(t, fmt.Sprintf("Parameters must be slice"), msgAndArgs...)
	}
	actualSlice := reflect.ValueOf(actual)
	expectedSlice := reflect.ValueOf(expected)
	for i := 0; i < actualSlice.Len(); i++ {
		result := InDelta(t, actualSlice.Index(i).Interface(), expectedSlice.Index(i).Interface(), delta, msgAndArgs...)
		if !result {
			return result
		}
	}
	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
}