testing: multiline example output comparison doesn't strip per-line whitespace

[josharian]

What steps will reproduce the problem?

1. Write a testing example that generates multiline output and in which interior lines
have trailing whitespace. For example, http://play.golang.org/p/3t5VyhWw7Z or
http://play.golang.org/p/nwSaMHGKU3.
2. go test


What is the expected output?

Interior lines' leading and trailing whitespace is stripped. The examples I provided
should pass.


What do you see instead?

Whitespace is stripped from the beginning of the first and the end of the last line
only. The examples I provided fail.


Which version are you using?  (run 'go version')

Reproduced with 1.1 and devel +5981425e55ce Tue Sep 17 16:54:22 2013 -0400 darwin/amd64


Please provide any additional information below.

The documentation doesn't strictly imply this behavior -- it says "(The comparison
ignores leading and trailing space.)". However, the fact that gofmt strips trailing
whitespace makes it hard to write certain examples (e.g. those involving raw HTTP
requests/responses) without this behavior.

[josharian]

Comment 1:

Fix sketched in https://golang.org/cl/13469045, for fun. Can't submit it now
due to Go 1.2 freeze.

[robpike]

Comment 2:

Labels changed: added priority-later, removed priority-triage.

Status changed to Accepted.

[rsc]

Comment 3:

hard to get that excited. gofmt will remove the spaces

[josharian]

Comment 4:

gofmt removing the spaces *is* the problem (in cases in which you need the spaces to
make the output match).

[adg]

Comment 5:

If you need explicit spacing, use a /* comment */ that gofmt will not touch.
I'm inclined to leave this WorkingAsIntended.

[josharian]

Comment 6:

That didn't occur to me.
Alas, gofmt inserts tabs at the beginning of each line to make /* comments */ line up
nicely, and those tabs show up as part of the expected output for non-first lines.

[josharian]

Comment 7:

Hmmm...the gofmt /* comments */ behavior seems to be under discussion in
https://golang.org/issue/5128. I guess this depends on what the
outcome of that is.

[adg]

Comment 8:

Oh, I'm sorry about that. I must have mis-remembered that issue.
I guess your solution is fine, then. Correctness shouldn't depend on leading or trailing
spaces. That's just too finicky.

[rsc]

Comment 9:

Labels changed: added go1.3maybe.

[rsc]

Comment 10:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 11:

Labels changed: added repo-main.

[robpike]

Comment 12:

I would prefer to see the output of the examples use exact matching because that's
easiest to specify and allows one to test exact output. For the rare examples for which
that is problematic, sanitize/regularlize the output before matching. That is, write
code.

[josharian]

Comment 13:

I think that this can be closed as WorkingAsIntended.

[adg]

Comment 14:

Status changed to WorkingAsIntended.

[josharian]

Comment 15:

Issue #9109 has been merged into this issue.

[jbeda]

I urge you to reopen this bug. As far as I can figure, there is no way to test output that has trailing whitespace in intermediate lines. At least I can't find an easy work around.

The examples at the top of the issue still don't work and can't, as far as I can figure, be made to work. I also can't make /* */ syntax work: http://play.golang.org/p/51D2DYVHTy