Greg Hendershott wrote on 11/6/18 9:56 AM:
I'd suggest writing to stderr the same location format used by rackunit.

OK, thank you (and David Storr).  I looked at the current RackUnit. How about the following proposal?

Proposal: A test failure message is a one-line message that:
* in DrRacket, includes the clickable error icons; and
* on the command line (or in Emacs, Vim, etc.), is to stderr, and includes the filename+line+column in a conventional non-Racket-specific format.


The reason I don't want to use the RackUnit message format exactly is that it has some excess stuff in it that won't work great with reporting many tests, like I tend do them in Overeasy.  Consider, for example, a dozen tests failing, and you can eyeball the dozen one-line messages at once to see whether they appear all related.

To implement the DrRacket clickable icons, it looks from "racket-7.1/share/racket/pkgs/rackunit-lib/rackunit/private/format.rkt" like I can do something like this simplified demo:

    #lang racket/base
    (with-handlers ((exn:fail? (lambda (exn)
                                 ((error-display-handler) (exn-message exn) exn))))       (error "TEST-FAILURE: [foomodule barproc empty-string] Expected 42, got 0."))

In DrRacket, that demo displays a concise single-line message, with the clickable icons:

    <ICONS> TEST-FAILURE: [foomodule barproc empty-string] Expected 42, got 0.

From the command line, that demo displays multi-line, which I don't want (mainly for the dozen-failures-eyeballing reason):

    TEST-FAILURE: [foomodule barproc empty-string] Expected 42, got 0.
       "/home/user/paddle-test-play.rkt": [running body]

So, how about the command line format omits the calling stack context, and instead uses a simple conventional one-line format that works out of the box with most tools, like one of:


where "PROGRAM" (if present) *might* be something like "TEST" or "TEST-FAILURE", instead of "my-racket-test-engine" or "raco test" or whatever Racket program invoked the tests.

BTW, that "[foomodule barproc empty-string]" part of the failure message is Overeasy's `test-section` symbolic way of identifying tests, which is complementary to source location, and meaningful to programmers/testers:

BTW, the "Expected ___, got ___." message would also have other forms, for different test pass criteria or ways that tests could fail.  That simple form is just for the most common case, of two sets of normal expression result values failing a equivalence check by `equal?`.

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