This test was written _after_ the fix was commited. However, I ran this
test against main without the fix and it failed. After running the test
with the tarball fix, it passed.

…date`

We had a conditional to skip validation for a package if the package
included the `tarball` key. However, this conditional always returned
false as it was nested inside a conditional that the package had the
default `package` key, which means it's not a tarball package, but a
package package (maybe we need better differentiation here). If we need
additional validation for tarballs down the road, we should do that one
level up. At this time we have no additional validaitons to add.

We initially included this fixture due to copy and pasting another
test. However, this `setUp` fixture isn't actually necessary for the
tarball dependency tests.