godoc Example output with CRLF

Question

I have written the following method:

func (c *Component) Encode(w io.Writer){
    //encodes c and writes the bytes into w, containing a few CRLF linebreaks
}

I also wrote the function demonstrating the encoder:

func ExampleComponent_Encode() {

    c := &Component{
        Name: "DESCRIPTION",
    }
    c.Encode(os.Stdout)
    //Output:
    //BEGIN:DESCRIPTION
    //END:DESCRIPTION
}

The Problem is now that this example fails the go test command because the linebreaks in the comments are \n linebreaks (I'm on Linux) while the linebreaks generated by c.Encode have to be \r\n(CRLF) linebreaks (as defined by some spec).

How can i get the example to not fail go test while also keeping it straightforward? Is there perhaps a way to hint go test/godoc on the linebreaks or get them to be more lenient?

I propably can hand-edit the linebreaks on these two lines or possibly the whole codebase but that will be pretty fragile and I want to avoid this solution.

Don't include the output in the example (or at least omit the `Output:`) header. Verify the correctness in a test instead. — Peter, Jun 23 '18 at 10:38
https://go.dev/issues/28822 contains some discussion. Using fmt.Print("\n") instead of fmt.Println() is a workaround. — Constantin Konstantinidis, Sep 17 '22 at 14:37

peterSO · Answer 1 · 2018-06-23T18:15:25.533

Redirect the Encode io.Writer to a buffer. In the buffer, replace CRLF (\r\n) with LF (\n) for the example output. For example,

example_test.go:

package main

import (
    "bytes"
    "fmt"
    "io"
    "os"
    "strings"
)

type Component struct{ Name string }

func (c *Component) Encode(w io.Writer) {
    //encodes c and writes the bytes into w, containing a few CRLF linebreaks
    w.Write([]byte("BEGIN:" + c.Name + "\r\n"))
    w.Write([]byte("END:" + c.Name + "\r\n"))
}

func ExampleComponent_Encode() {
    var buf bytes.Buffer
    c := &Component{
        Name: "DESCRIPTION",
    }
    c.Encode(&buf)

    output := strings.Replace(buf.String(), "\r\n", "\n", -1)
    fmt.Fprintf(os.Stdout, "%s", output)
    //Output:
    //BEGIN:DESCRIPTION
    //END:DESCRIPTION
}

Output:

$ go test -v example_test.go
=== RUN   ExampleComponent_Encode
--- PASS: ExampleComponent_Encode (0.00s)
PASS

godoc Example output with CRLF

1 Answers1