Acid
137 lines
2.8 KiB
Go
137 lines
2.8 KiB
Go
package tests
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import (
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"math/rand"
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"slices"
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"testing"
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"datastructures/trees/heap"
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)
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func TestPQPopEmpty(t *testing.T) {
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q := heap.NewPriorityQueue[int]()
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if v, ok := q.Pop(); ok {
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t.Fatalf("Pop on empty queue = (%d, true), want (0, false)", v)
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}
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}
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func TestPQPeekEmpty(t *testing.T) {
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q := heap.NewPriorityQueue[int]()
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if v, ok := q.Peek(); ok {
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t.Fatalf("Peek on empty queue = (%d, true), want (0, false)", v)
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}
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}
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func TestPQSizeTracksPushPop(t *testing.T) {
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q := heap.NewPriorityQueue[int]()
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if q.Size() != 0 {
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t.Fatalf("new queue Size = %d, want 0", q.Size())
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}
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for i, v := range []int{9, 4, 7, 1} {
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q.Push(v)
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if q.Size() != i+1 {
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t.Fatalf("after %d pushes Size = %d, want %d", i+1, q.Size(), i+1)
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}
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}
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for want := 3; want >= 0; want-- {
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q.Pop()
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if q.Size() != want {
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t.Fatalf("Size = %d, want %d", q.Size(), want)
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}
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}
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}
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func TestPQPeekReturnsMinWithoutRemoving(t *testing.T) {
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q := heap.NewPriorityQueue[int]()
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for _, v := range []int{8, 3, 5, 1, 9} {
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q.Push(v)
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}
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v, ok := q.Peek()
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if !ok || v != 1 {
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t.Fatalf("Peek = (%d, %v), want (1, true)", v, ok)
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}
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// Peek must not mutate the queue.
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if q.Size() != 5 {
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t.Fatalf("Size after Peek = %d, want 5", q.Size())
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}
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v2, _ := q.Peek()
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if v2 != v {
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t.Fatalf("second Peek = %d, want same %d", v2, v)
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}
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}
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func TestPQPopsInPriorityOrder(t *testing.T) {
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in := []int{5, 3, 8, 1, 9, 2, 7, 0, 4, 6}
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q := heap.NewPriorityQueue[int]()
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for _, v := range in {
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q.Push(v)
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}
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got := []int{}
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for q.Size() > 0 {
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// Peek must always agree with the next Pop.
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p, ok := q.Peek()
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if !ok {
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t.Fatal("Peek returned ok=false while Size > 0")
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}
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v, ok := q.Pop()
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if !ok {
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t.Fatal("Pop returned ok=false while Size > 0")
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}
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if p != v {
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t.Fatalf("Peek returned %d but Pop returned %d", p, v)
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}
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got = append(got, v)
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}
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want := slices.Clone(in)
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slices.Sort(want)
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if !slices.Equal(got, want) {
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t.Fatalf("pop order = %v, want ascending %v", got, want)
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}
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}
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func TestPQStrings(t *testing.T) {
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q := heap.NewPriorityQueue[string]()
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for _, s := range []string{"pear", "apple", "cherry", "banana"} {
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q.Push(s)
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}
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got := []string{}
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for q.Size() > 0 {
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v, _ := q.Pop()
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got = append(got, v)
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}
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want := []string{"apple", "banana", "cherry", "pear"}
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if !slices.Equal(got, want) {
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t.Fatalf("pop order = %v, want %v", got, want)
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}
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}
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func TestPQFuzzAgainstSort(t *testing.T) {
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rng := rand.New(rand.NewSource(7))
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for trial := 0; trial < 200; trial++ {
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n := rng.Intn(50)
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in := make([]int, n)
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for i := range in {
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in[i] = rng.Intn(100)
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}
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q := heap.NewPriorityQueue[int]()
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for _, v := range in {
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q.Push(v)
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}
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got := []int{}
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for q.Size() > 0 {
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v, _ := q.Pop()
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got = append(got, v)
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}
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want := slices.Clone(in)
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slices.Sort(want)
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if !slices.Equal(got, want) {
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t.Fatalf("trial %d: got %v, want %v (input %v)", trial, got, want, in)
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}
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}
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}
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