Add to Gribi Get() tests validation that the correct status is returned

[gggsmith]

The test verifies for Gribi Modify call that after receiving FIB_ACK programming status, Gribi Get calls return FIB_PROGRAMMED status for programmed entries. This is part of Gribi specification https://github.com/openconfig/gribi/blob/master/doc/specification.md#4133-life-cycle-of-an-aft-operation

[robshakir]

@gggsmith Happy to take a look at this PR -- can we make the build check pass?

Thanks,
r.

[robshakir]

Suggested change

	if ipv4, ok := ni.ipv4[v.Ipv4.GetPrefix()]; !ok {
	t.Fatalf("did not find entry, did not find ipv4: %s, got: %s\n", v.Ipv4, getres)
	} else {
	programmedStatusMatch(t, ipv4, wantProto)
	ipv4, ok := ni.ipv4[v.Ipv4.GetPrefix()]
	if !ok {
	t.Fatalf("did not find entry, did not find ipv4: %s, got: %s\n", v.Ipv4, getres)
	}
	programmedStatusMatch(t, ipv4, wantProto)

[robshakir]

Suggest this layout here and above to avoid the indentation of the other case -- since the !ok case will exit via Fatalf we don't really need the else.

[robshakir]

This will lead -- in some cases -- to having WithFIBProgrammed(RIB_PROGRAMMED) which seems erroneous right? i.e., we will never have a fib_status field return RIB_PROGRAMMED right?

Instead, should we either have WithProgrammedStatus() which could take arguments of FIB ACKed or RIB ACKed? Or alternatively, WithFIBProgrammedStatus which only allows for FIB ACK or failed?