| 1 | package calls |
| 2 | |
| 3 | import ( |
| 4 | "testing" |
| 5 | "time" |
| 6 | ) |
| 7 | |
| 8 | // Task 5 review minor 5: unit coverage for ratelimit.go's own behaviour, |
| 9 | // independent of the signal endpoint that happens to be its only caller. |
| 10 | |
| 11 | func TestRateLimiterAllowsUpToBurstThenRefuses(t *testing.T) { |
| 12 | now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC) |
| 13 | l := newRateLimiter(30, 3, 0) |
| 14 | for i := 0; i < 3; i++ { |
| 15 | if ok, _ := l.allow("k", now); !ok { |
| 16 | t.Fatalf("call %d within burst was refused", i) |
| 17 | } |
| 18 | } |
| 19 | ok, retry := l.allow("k", now) |
| 20 | if ok { |
| 21 | t.Fatal("a call past the burst, with no time elapsed, was allowed") |
| 22 | } |
| 23 | if retry <= 0 { |
| 24 | t.Fatalf("retryAfter %v, want > 0", retry) |
| 25 | } |
| 26 | } |
| 27 | |
| 28 | func TestRateLimiterRefillsAfterAnExplicitElapsedDuration(t *testing.T) { |
| 29 | now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC) |
| 30 | l := newRateLimiter(30, 1, 0) |
| 31 | if ok, _ := l.allow("k", now); !ok { |
| 32 | t.Fatal("the first call, at burst, was refused") |
| 33 | } |
| 34 | if ok, _ := l.allow("k", now); ok { |
| 35 | t.Fatal("a second call at the same instant was allowed with an empty bucket") |
| 36 | } |
| 37 | // One token at 30/s refills in 1/30 s ≈ 33 ms; 40 ms is comfortably |
| 38 | // past that. |
| 39 | later := now.Add(40 * time.Millisecond) |
| 40 | if ok, _ := l.allow("k", later); !ok { |
| 41 | t.Fatal("a call after the refill window was still refused") |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | func TestRateLimiterRetryAfterIsBoundedByOneTokensRefillTime(t *testing.T) { |
| 46 | now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC) |
| 47 | l := newRateLimiter(30, 1, 0) |
| 48 | l.allow("k", now) |
| 49 | _, retry := l.allow("k", now) |
| 50 | oneToken := time.Second / 30 |
| 51 | if retry <= 0 || retry > oneToken+time.Millisecond { |
| 52 | t.Fatalf("retryAfter %v, want in (0, %v]", retry, oneToken) |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | func TestRateLimiterEvictsABucketIdleOverAMinute(t *testing.T) { |
| 57 | now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC) |
| 58 | l := newRateLimiter(30, 60, 0) |
| 59 | l.allow("k", now) |
| 60 | |
| 61 | l.mu.Lock() |
| 62 | l.sweepLocked(now.Add(59 * time.Second)) |
| 63 | _, stillThereAt59s := l.buckets["k"] |
| 64 | l.sweepLocked(now.Add(61 * time.Second)) |
| 65 | _, stillThereAt61s := l.buckets["k"] |
| 66 | l.mu.Unlock() |
| 67 | |
| 68 | if !stillThereAt59s { |
| 69 | t.Fatal("a bucket under a minute idle was swept early") |
| 70 | } |
| 71 | if stillThereAt61s { |
| 72 | t.Fatal("a bucket over a minute idle was not swept") |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | func TestRateLimiterCapEvictsTheLeastRecentlyTouchedBucket(t *testing.T) { |
| 77 | now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC) |
| 78 | l := newRateLimiter(30, 60, 2) |
| 79 | l.allow("a", now) |
| 80 | l.allow("b", now.Add(time.Second)) |
| 81 | |
| 82 | l.mu.Lock() |
| 83 | n := len(l.buckets) |
| 84 | l.mu.Unlock() |
| 85 | if n != 2 { |
| 86 | t.Fatalf("buckets after two distinct keys: %d, want 2", n) |
| 87 | } |
| 88 | |
| 89 | // A third key must not grow the map past the cap: "a", the oldest, |
| 90 | // is evicted to make room. |
| 91 | l.allow("c", now.Add(2*time.Second)) |
| 92 | |
| 93 | l.mu.Lock() |
| 94 | _, aStillThere := l.buckets["a"] |
| 95 | _, bStillThere := l.buckets["b"] |
| 96 | _, cThere := l.buckets["c"] |
| 97 | size := len(l.buckets) |
| 98 | l.mu.Unlock() |
| 99 | |
| 100 | if size > 2 { |
| 101 | t.Fatalf("bucket count %d exceeds the cap of 2", size) |
| 102 | } |
| 103 | if aStillThere { |
| 104 | t.Fatal("the least recently touched bucket ('a') was not evicted to make room") |
| 105 | } |
| 106 | if !bStillThere || !cThere { |
| 107 | t.Fatal("a bucket newer than the one evicted was lost instead") |
| 108 | } |
| 109 | } |
| 110 | |
amadan