| 1 | package analytics |
| 2 | |
| 3 | import "testing" |
| 4 | |
| 5 | func TestTopKExactBelowCapAndBoundedAbove(t *testing.T) { |
| 6 | k := NewTopK() |
| 7 | for i := 0; i < 100; i++ { |
| 8 | k.Add("/p"+itoa(i), int64(i+1)) |
| 9 | } |
| 10 | f := k.Fold() |
| 11 | if len(f) != 100 || f["/p99"] != 100 || k.Approximate() { |
| 12 | t.Fatalf("below cap must be exact: len=%d p99=%d approx=%v", len(f), f["/p99"], k.Approximate()) |
| 13 | } |
| 14 | for i := 0; i < 2000; i++ { |
| 15 | k.Add("/q"+itoa(i), 1) |
| 16 | } |
| 17 | f = k.Fold() |
| 18 | if len(f) > TopKSize+1 || !k.Approximate() || f[OtherKey] == 0 { |
| 19 | t.Fatalf("above cap: len=%d approx=%v other=%d", len(f), k.Approximate(), f[OtherKey]) |
| 20 | } |
| 21 | // Total mass is conserved between counters and _other. |
| 22 | var total int64 |
| 23 | for _, v := range f { |
| 24 | total += v |
| 25 | } |
| 26 | if total != 100*101/2+2000 { |
| 27 | t.Fatalf("mass %d", total) |
| 28 | } |
| 29 | // A heavy hitter survives. |
| 30 | if f["/p99"] < 100-2000/TopKSize { |
| 31 | t.Fatalf("heavy hitter undercounted: %d", f["/p99"]) |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | func TestTopKMergeRefolds(t *testing.T) { |
| 36 | a, b := NewTopK(), NewTopK() |
| 37 | for i := 0; i < 400; i++ { |
| 38 | a.Add("/a"+itoa(i), 2) |
| 39 | b.Add("/b"+itoa(i), 3) |
| 40 | } |
| 41 | a.Merge(b) |
| 42 | f := a.Fold() |
| 43 | if len(f) > TopKSize+1 || f[OtherKey] == 0 { |
| 44 | t.Fatalf("merged 800 keys must fold to ≤501: %d", len(f)) |
| 45 | } |
| 46 | r := TopKFrom(f) |
| 47 | if r.other != f[OtherKey] || len(r.counts) != len(f)-1 { |
| 48 | t.Fatal("TopKFrom must invert Fold") |
| 49 | } |
| 50 | long := NewTopK() |
| 51 | long.Add(string(make([]byte, 300)), 1) |
| 52 | for key := range long.Fold() { |
| 53 | if len(key) > MaxKeyLen { |
| 54 | t.Fatal("keys must be capped at 256 bytes") |
| 55 | } |
| 56 | } |
| 57 | } |
| 58 | |
amadan