Add back error cases tests.

[bwplotka]

Some tests were removed in #122 - we need to get them back.

See commented code in

bingo/get_e2e_test.go

Line 241 in f2324ff

func TestGet_Errors(t *testing.T) {

and

bingo/get_e2e_test.go

Line 490 in f2324ff

func TestGet_ModuleCases(t *testing.T) {