1// Copyright 2021 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package fuzz
6
7import "testing"
8
9func TestQueue(t *testing.T) {
10	// Zero valued queue should have 0 length and capacity.
11	var q queue
12	if n := q.len; n != 0 {
13		t.Fatalf("empty queue has len %d; want 0", n)
14	}
15	if n := q.cap(); n != 0 {
16		t.Fatalf("empty queue has cap %d; want 0", n)
17	}
18
19	// As we add elements, len should grow.
20	N := 32
21	for i := 0; i < N; i++ {
22		q.enqueue(i)
23		if n := q.len; n != i+1 {
24			t.Fatalf("after adding %d elements, queue has len %d", i, n)
25		}
26		if v, ok := q.peek(); !ok {
27			t.Fatalf("couldn't peek after adding %d elements", i)
28		} else if v.(int) != 0 {
29			t.Fatalf("after adding %d elements, peek is %d; want 0", i, v)
30		}
31	}
32
33	// As we remove and add elements, len should shrink and grow.
34	// We should also remove elements in the same order they were added.
35	want := 0
36	for _, r := range []int{1, 2, 3, 5, 8, 13, 21} {
37		s := make([]int, 0, r)
38		for i := 0; i < r; i++ {
39			if got, ok := q.dequeue(); !ok {
40				t.Fatalf("after removing %d of %d elements, could not dequeue", i+1, r)
41			} else if got != want {
42				t.Fatalf("after removing %d of %d elements, got %d; want %d", i+1, r, got, want)
43			} else {
44				s = append(s, got.(int))
45			}
46			want = (want + 1) % N
47			if n := q.len; n != N-i-1 {
48				t.Fatalf("after removing %d of %d elements, len is %d; want %d", i+1, r, n, N-i-1)
49			}
50		}
51		for i, v := range s {
52			q.enqueue(v)
53			if n := q.len; n != N-r+i+1 {
54				t.Fatalf("after adding back %d of %d elements, len is %d; want %d", i+1, r, n, n-r+i+1)
55			}
56		}
57	}
58}
59