Use table tests instead of helpers.PreparerValidator

[BrianHicks]

Once #142 is merged, PreparerValidator will be in the code. It should be removed in favor of something like http://dave.cheney.net/2013/06/09/writing-table-driven-tests-in-go

[Dacode45]

Well I also made a CheckValidator and ApplyValidator as well as a few other questionable helpers (e.g SquashChecks). I'd rather not introduce bad practices in the codebase. I could refactor them into a /helpers/testing package

[Dacode45]

Instead of putting it in helpers, I could put it in the resource package, and make generic table test for task and prepares?

[BrianHicks]

No, it probably should be table tests in each of the test files if you really need them. I noticed a lot of the places where it's being used are just single checks. Helper functions in each module may make more sense.

[sehqlr]

Here is a sample of a table test that can replace the two test cases and that helper func. It's based on the unmerged changes, so I won't open a PR until that is merged.

func TestPreparerTableTest(t *testing.T) {
    t.Parallel()

    fr := fakerenderer.FakeRenderer{}
    prepTests := []struct {
        prep resource.Resource
        err  error
    }{
        {
            &absent.Preparer{Destination: "/path/to/absent"},
            nil,
        },
        {
            &absent.Preparer{},
            errors.New("resource requires a `destination` parameter"),
        },
    }

    for _, prepTest := range prepTests {
        _, err := prepTest.prep.Prepare(&fr)
        assert.Equal(t, err, prepTest.err)
    }
}

[BrianHicks]

This issue has gone pretty stale. I'm going to close it. We'll fix tests as we go.