Improve panic output with rows.AddRow

[co60ca]

Proposal

go-sqlmock/rows.go

Line 169 in b2f0b45

panic("Expected number of values to match number of columns")

This panic can be confusing, its simple enough to debug if you know what you're doing but if you pass a string withlen() = 25 it will of course panic if the developer does not spreading. Like with: rows.AddRow(v) vs rows.AddRow(v...) (Spreading will cause another issue with []string but I digress.

The former will compile but will panic. I wonder if you'd accept it to say "Expected number of values to match number of columns, expected %d, actual %d" to at least hint.

I wonder if this is acceptable or if it would break backwards compatibility in an unacceptable way. If you'd accept this change I'd gladly provide a PR.

Use-cases

Changing the panic message should simplify debugging sqlmock during development.

Otherwise we can close.

[JessieAMorris]

This sounds like a pretty reasonable change. It’s possible it might break something, but a panic isn’t something that would be checked against super frequently so I see it as a pretty low risk change.

[co60ca]

@JessieAMorris please consider my PR and thank you.