1 package lb
2
3 import (
4 "context"
5 "math"
6 "testing"
7
8 "github.com/go-kit/kit/endpoint"
9 "github.com/go-kit/kit/sd"
10 )
11
12 func TestRandom(t *testing.T) {
13 var (
14 n = 7
15 endpoints = make([]endpoint.Endpoint, n)
16 counts = make([]int, n)
17 seed = int64(12345)
18 iterations = 1000000
19 want = iterations / n
20 tolerance = want / 100
21 )
22
23 for i := 0; i < n; i++ {
24 i0 := i
25 endpoints[i] = func(context.Context, interface{}) (interface{}, error) { counts[i0]++; return struct{}{}, nil }
26 }
27
28 endpointer := sd.FixedEndpointer(endpoints)
29 balancer := NewRandom(endpointer, seed)
30
31 for i := 0; i < iterations; i++ {
32 endpoint, _ := balancer.Endpoint()
33 endpoint(context.Background(), struct{}{})
34 }
35
36 for i, have := range counts {
37 delta := int(math.Abs(float64(want - have)))
38 if delta > tolerance {
39 t.Errorf("%d: want %d, have %d, delta %d > %d tolerance", i, want, have, delta, tolerance)
40 }
41 }
42 }
43
44 func TestRandomNoEndpoints(t *testing.T) {
45 endpointer := sd.FixedEndpointer{}
46 balancer := NewRandom(endpointer, 1415926)
47 _, err := balancer.Endpoint()
48 if want, have := ErrNoEndpoints, err; want != have {
49 t.Errorf("want %v, have %v", want, have)
50 }
51
52 }
53
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