Ability to specify comment when asserting with So()

[XANi]

When checking if multiple fields in output struct are correct it would be useful to have ability to add comment to So() instead of just getting a line number of failed assert eg.

tested, err := NewHostFromMap(m)
    Convey("HostFromMap", t, func() {
        So(err, ShouldEqual, nil)
        So(tested.Hostname, ShouldEqual, m["host_name"])
        So(tested.State, ShouldEqual, "WARNING")
        So(tested.PreviousState, ShouldEqual, "OK")
        So(tested.CheckMessage, ShouldEqual, "DUMMY CHECK WARNING")
        ...

will just generate failures with only line number as an info, to get meaningful feedback I have to use much more verbose (and IMO much less readable) format:

tested, err := NewServiceFromMap(m)
Convey("ServiceFromMap", t, func() {
    Convey("no err", func() {
        So(err, ShouldEqual, nil)
    })
    Convey("Hostname", func() {
        So(tested.Hostname, ShouldEqual, m["host_name"])
    })
    Convey("Description", func() {
        So(tested.Description, ShouldEqual, m["service_description"])
    })
    Convey("State", func() {
        So(tested.State, ShouldEqual, "WARNING")
    })
    ...

It would be nice if it would be possible just to have something like

        So(tested.Hostname, ShouldEqual, m["host_name"], "Hostname")
        So(tested.State, ShouldEqual, "WARNING", "State")

and have that last field as a comment next to filename:line

[mdwhatcott]

You know about ShouldResemble for comparing structs, right?

[XANi]

Well, I've tried:

but I wouldn't call that an improvement as it only works if created struct is 100% identical to compared data.

Also it is kinda hard to even find a difference in that view

[mdwhatcott]

Ok, thanks for clarifying. I've struggled with this same frustrating problem.

Modifying the signature to the So call is a pretty significant change that would ripple all the way into every function of the assertions package (if you want the message to appear along with the line:file info. That's a lot to work through. So, while I'm not completely against this, I'm not sold on it yet either.

[XANi]

Maybe instead variation on Convey() (with name like ConveySimple, or ConveyOne or sth) that would work like Convey with single So:

Convey("Hostname", t, tested.Hostname, ShouldEqual, "testhost")

That would cut on convey blocks that are just single assertion without cutting down on readability

[mdwhatcott]

Yeah, we've actually thought about that too at one point. It was complicated when we discussed it at that time and the internals of the convey package have been almost completely rewritten since then so I don't think I could estimate the complexity of the task.

Perhaps you would consider creating a simple assertion function using the assertions package by itself (without the convey package)?

func assertEqual(expected, actual interface{}, message string, t *testing.T) {
    if ok, message := assertions.So(x.something, ShouldEqual, y.something); !ok {
        t.Error(message)
    }
}

[XANi]

Well, just adding

func ConveyOne(s string, c1 interface{}, assert assertion, c2 interface{}) {
    ctx := getCurrentContext()
    ctx.Convey(s, func() {
        ctx.So(c1, assert, c2)
    })
}

(and ofc adding to to C interface{} ) seems to work well enough altho it would require a bit more work to work in root context and I dont really know Go that well.

Also why there is code in doc.go ? Shouldn't that be "documentation only" file ? Took me ages to find where is the interface because every time that file popped up I assumed it is just some piece of docs and not actual function/interface

[mdwhatcott]

Good question about the doc.go file. The original thinking with that file was to put all the exported names there. The project has since grown. Maybe that file should be called convey.go now...

You are welcome to move forward with what you are proposing, taking care to not cause any breaking changes to the exported API/contract.

[kormat]

The ConveyOne-type solution doesn't solve the case where you're iterating over values. The only way to fix that that i can see is to go to the pain of adding a So variant that supports a message (maybe called SoMsg?). Otherwise you're stuck with the suggestion @mdwhatcott made here #355 (comment), and lose a lot of the convey benefits.