在Go中，使用Example…测试方法时，有一种方法可以让它显示差异而不是得到……想要…？

Question

I've been using go for a bigger project and love it, and for my testing i've been using the

func ExampleXxx {
    ... code ...
    //Output:
    //...expected output ...
}

method for testing. When it fails it will say

got:
... bunch of lines showing the output of test ...
want:
... the comment you put in to show what you expected ...

is there any way to make it show just the difference? I can take the two and copy to separate files and run a diff etc, but I'd much rather just have it show the parts that were wrong as some of my tests have longer output.

Thanks in advance

EDIT:

I'm using http://golang.org/pkg/testing/#hdr-Examples and want the output to show a diff not the current output. I know I can do the diff manually.

Answer 1

No, you cannot do this. This is not the intended use of Examples.

Examples are a nice way to show how some function will behave: Examples exists to document. The main reason for validating the example output is to make sure the Examples are valid/correct, not that your code is okay. For the later you have Test functions

Most often the output of an Example displays input and output (or just output) of one invocation of a certain function/method per line; sometimes Examples use the different lines to show parts of a complex result, e.g. one line per element of the returned slice.

I think your use of Examples to "verify the flow of my program" contradicts the intention of Examples. I would use Test functions and use any of the available diff tools to generate a got, want, diff output myself if I'd like to test e.g. a text processor on large bunches of input.