Add importer for github.com/LK4D4/vndr

[spenczar]

This was motivated by working on something that imports github.com/moby/moby, which uses github.com/LK4D4/vndr. I understand that, in the future, dep will use importers to understand the manifests of transitive dependencies to construct an appropriate dependency graph. That would be really useful when working with moby!

@carolynvs, thanks for your guidance in slack. I followed the pattern set by godep_importer.go and glide_importer.go.

[carolynvs]

THIS LOOKS AWESOME! 🎉

Would you please also add an end-to-end test? I suggest copying and tweaking the godep test from here: https://github.com/golang/dep/tree/master/cmd/dep/testdata/harness_tests/init/godep/case1

To run just that single test you can use:

go test -run TestIntegration/init/vndr ./cmd/dep -v -logs

[carolynvs]

Note to self: If #952 is merged first, we should use the constructor dep.NewManifest.

[spenczar]

The race is on! 🏁

[carolynvs]

My apologies for not giving a heads up that this was incoming before you started... Another PR was just merged which switched the importers to table based tests. Below is an example of how the tests should look now. I hope it's not too much trouble to update the tests here to match, let me know if they don't line up well, I see you are testing slightly differently (using deep equal).

dep/cmd/dep/godep_importer_test.go

Lines 21 to 49 in 044c4ef

	func TestGodepConfig_Convert(t *testing.T) {
	testCases := map[string]struct {
	json godepJSON
	wantConvertErr bool
	matchPairedVersion bool
	projectRoot gps.ProjectRoot
	wantConstraint string
	wantRevision gps.Revision
	wantVersion string
	wantLockCount int
	}{
	"convert project": {
	json: godepJSON{
	Imports: []godepPackage{
	{
	ImportPath: "github.com/sdboyer/deptest",
	// This revision has 2 versions attached to it, v1.0.0 & v0.8.0.
	Rev: "ff2948a2ac8f538c4ecd55962e919d1e13e74baf",
	Comment: "v0.8.0",
	},
	},
	},
	matchPairedVersion: true,
	projectRoot: gps.ProjectRoot("github.com/sdboyer/deptest"),
	wantConstraint: "^0.8.0",
	wantRevision: gps.Revision("ff2948a2ac8f538c4ecd55962e919d1e13e74baf"),
	wantVersion: "v0.8.0",
	wantLockCount: 1,
	},

[spenczar]

No problem, this was pretty easy to do.

There's now a lot of repeated code between the three importers, though. I've got a sketch of how this could be resolved in spenczar/dep@vndr_importer...importer_test_refactor. It makes things a more abstract, which is bad, but it reduces the code duplication, which is good. If you think this is a net positive, let me know and I'll make an actual PR - up to you, I can see it either way.

[carolynvs]

@spenczar Oops! I missed this comment until just now. Want to take a look at #992? I think we both approached it about the same.

[carolynvs]

I know that moby uses short git hashes, which is a bit of a problem. I think it would be easiest to have that be a separate issue, so I created #987 to address that part.

[AlekSi]

Poke @LK4D4