(t *testing.T)
| 124 | } |
| 125 | |
| 126 | func TestTokenForIDCollision(t *testing.T) { |
| 127 | // Estimate the hash collision rate of tokenForID. |
| 128 | |
| 129 | n := 1_000_000 |
| 130 | h := util.NewTokenHasher() |
| 131 | buf := make([]byte, 4) |
| 132 | |
| 133 | tokens := map[token]struct{}{} |
| 134 | IDs := [][]byte{} |
| 135 | |
| 136 | spanID := make([]byte, 8) |
| 137 | for i := 0; i < n; i++ { |
| 138 | _, err := crand.Read(spanID) |
| 139 | require.NoError(t, err) |
| 140 | |
| 141 | cpy := append([]byte(nil), spanID...) |
| 142 | IDs = append(IDs, cpy) |
| 143 | |
| 144 | tokens[token(util.TokenForID(h, buf, 0, spanID))] = struct{}{} |
| 145 | } |
| 146 | |
| 147 | // Ensure no duplicate span IDs accidentally generated |
| 148 | sort.Slice(IDs, func(i, j int) bool { |
| 149 | return bytes.Compare(IDs[i], IDs[j]) == -1 |
| 150 | }) |
| 151 | for i := 1; i < len(IDs); i++ { |
| 152 | if bytes.Equal(IDs[i-1], IDs[i]) { |
| 153 | panic("same span ID was generated, oops") |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | missing := n - len(tokens) |
| 158 | if missing > 0 { |
| 159 | fmt.Printf("missing 1 out of every %.2f spans", float32(n)/float32(missing)) |
| 160 | } |
| 161 | |
| 162 | // There shouldn't be any collisions. |
| 163 | require.Equal(t, n, len(tokens)) |
| 164 | } |
| 165 | |
| 166 | func BenchmarkCombine(b *testing.B) { |
| 167 | parts := []int{2, 3, 4, 8} |
nothing calls this directly
no test coverage detected