Function TestReferenceHashBalancer

balancer_test.go:66–123

(t *testing.T)

}

func TestReferenceHashBalancer(t *testing.T) {
	testCases := map[string]struct {
		Key               []byte
		Hasher            hash.Hash32
		Partitions        []int
		Partition         int
		RndBalancerResult int
	}{
		"nil": {
			Key:               nil, // nil key means random partition
			Partitions:        []int{0, 1, 2},
			Partition:         123,
			RndBalancerResult: 123,
		},
		"partition-0": {
			Key:        []byte("blah"),
			Partitions: []int{0, 1},
			Partition:  0,
		},
		"partition-1": {
			Key:        []byte("blah"),
			Partitions: []int{0, 1, 2},
			Partition:  1,
		},
		"partition-2": {
			Key:        []byte("castle"),
			Partitions: []int{0, 1, 2},
			Partition:  2,
		},
		"custom hash": {
			Key:        []byte("boop"),
			Hasher:     crc32.NewIEEE(),
			Partitions: []int{0, 1, 2},
			Partition:  1,
		},
		"hash code with MSB set": {
			Key:        []byte("20"),
			Partitions: []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
			Partition:  15,
		},
	}

	for label, test := range testCases {
		t.Run(label, func(t *testing.T) {
			var rr randomBalancer
			if test.Key == nil {
				rr.mock = test.RndBalancerResult
			}

			msg := Message{Key: test.Key}
			h := ReferenceHash{Hasher: test.Hasher, rr: rr}
			partition := h.Balance(msg, test.Partitions...)
			if partition != test.Partition {
				t.Errorf("expected %v; got %v", test.Partition, partition)
			}
		})
	}
}