Add test for customDecoder messages and fix typo in messages

[noahzgordon]

#639 was closed because @evancz came across the same issue and fixed it in the same way, adding some useful context information. This PR extends the test from #639 to fit his implementation. It also changes the error message to use the function name customDecoder, which was misspelled as @jvoigtlaender points out in elm-lang@7f6e518

[process-bot]

Thanks for the pull request! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[process-bot]

Thanks for the pull request! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[evancz]

Looks good. Can you make the test use String.contains though? I don't think it makes sense to encode the particular wording of the error message in the test, but it does make sense to make sure the users messages appears somewhere in the error message.

[evancz]

Looks good. Can you make the test use String.contains though? I don't think it makes sense to encode the particular wording of the error message in the test, but it does make sense to make sure the users messages appears somewhere in the error message.

[noahzgordon]

Sounds better. On it.

[noahzgordon]

Sounds better. On it.

[noahzgordon]

Updated with your suggestion.

It gets a bit funky when testing anything but equality for Err values, since to operate on the Err string you have to pattern match and then handle the possibility of Ok values. I've handled this in my projects my using Debug.crash to raise with an informative message on the Ok branch, so that's what I've done here. Let me know if you've found a better solution.

[noahzgordon]

Updated with your suggestion.

It gets a bit funky when testing anything but equality for Err values, since to operate on the Err string you have to pattern match and then handle the possibility of Ok values. I've handled this in my projects my using Debug.crash to raise with an informative message on the Ok branch, so that's what I've done here. Let me know if you've found a better solution.

[evancz]

Probably better to use pass and fail to create the assertion.

[evancz]

Probably better to use pass and fail to create the assertion.

[noahzgordon]

Cool, didn't know about those functions. Updated to use fail.

[noahzgordon]

Cool, didn't know about those functions. Updated to use fail.

[evancz]

Thanks!

[evancz]

Thanks!

[noahzgordon]

First commits to core! 🎉🎉🎉

[noahzgordon]

First commits to core! 🎉🎉🎉