package main

import (
    "reflect"
    "testing"
)

type ErrorType struct {
    Description string
}

func TestGoCompileError(t *testing.T) {
    var theError = badFunc("AAAAAAAAAAAAAAAAAAAAAA")
    if reflect.DeepEqual([]byte(theError.Description), []byte("AAAAAAAAAAAAAAAAAAAAAADDDDDDDDDDD")) == false { // 22 + 11 chars = 33 chars in the output
        t.Fatal("Test that shouldn't have failed have failed")
    }

    theError = badFunc("AAAAAAAAAAAAAAAAAAAAA")
    if reflect.DeepEqual([]byte(theError.Description), []byte("AAAAAAAAAAAAAAAAAAAAADDDDDDDDDDD")) == false { // 21 chars + 11 chars = 32 chars in the output, fails for char count <= 32
        t.Fatalf("Got %v bytes, expected %v", []byte(theError.Description), []byte("AAAAAAAAAAAAAAAAAAAAADDDDDDDDDDD"))
    }
}

func badFunc(input string) *ErrorType {
    var testSlice = []string{}
    testSlice = append(testSlice, input)
    var outputString = ""
    outputString = testSlice[0] + "DDDDDDDDDDD" // 11 chars

    return NewError(outputString)
}

func NewError(description ...string) *ErrorType {
    return &ErrorType{
        Description: func() string {
            if len(description) > 0 {
                return description[0]
            }

            return "Another error"
        }(),
    }
}

$ go test 
--- FAIL: TestGoCompileError (0.00s)
    main_test.go:20: Got [32 0 0 0 0 0 0 0 43 42 4 0 0 0 0 0 192 128 10 32 200 0 0 0 232 141 4 32 200 0 0 0] bytes, expected [65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 68 68 68 68 68 68 68 68 68 68 68]
FAIL
exit status 1