Added metadata test for GenericMap.resample

[mdmueller]

As addressed in issue #760. I also made the other resample test a bit more concise.

[coveralls]

Coverage remained the same when pulling 3fbf15b on amras1:genericmap-resample-testing into ee1d14f on sunpy:master.

[dpshelio]

PR Looks very nice! 👍

I'm thinking if we should just change size and coordinates on the header of a resample image, or if we should also add something in the history, so whoever finds a resample file later on knows it has been resampled.

[rhewett]

Isn't it easier to tell which test failed under the old version?

[dpshelio]

I was thinking the same... but if it fails you get the value tested within the error message, so at least the dimensions will tell you which one was used. I think.

I'm not saying that's easier to tell though. But from a list of 4 is quite easy.

[Cadair]

@derdon Can't we use some pytest magic here?

[mdmueller]

Fixed the spaces around =, is there a convenient way to give more information about the assertion using pytest? I couldn't find anything except assert foo == bar, msg which loses introspection.

[coveralls]

Coverage increased (+0.53%) when pulling 1eb932a on amras1:genericmap-resample-testing into ee1d14f on sunpy:master.

[derdon]

You usually don't need a custom message because the output of py.test is quite helpful. Just use assert out == expted

[Cadair]

Can't we use pytest parametrize to make this cleaner? https://pytest.org/latest/example/parametrize.html

[rhewett]

Yes, this is how it should be done. Then, each one will count as a different test, too, which they should.

[mdmueller]

Okay fixed, hopefully pytest will report enough info now.

[coveralls]

Coverage remained the same when pulling 630d8d2 on amras1:genericmap-resample-testing into ee1d14f on sunpy:master.

[Cadair]

👍 from me.