1 files changed, 213 insertions, 0 deletions
diff --git a/src/container/heap/heap_test.go b/src/container/heap/heap_test.go
new file mode 100644
index 000000000..b3d054c5f
--- /dev/null
+++ b/src/container/heap/heap_test.go
@@ -0,0 +1,213 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package heap
+
+import (
+	"math/rand"
+	"testing"
+)
+
+type myHeap []int
+
+func (h *myHeap) Less(i, j int) bool {
+	return (*h)[i] < (*h)[j]
+}
+
+func (h *myHeap) Swap(i, j int) {
+	(*h)[i], (*h)[j] = (*h)[j], (*h)[i]
+}
+
+func (h *myHeap) Len() int {
+	return len(*h)
+}
+
+func (h *myHeap) Pop() (v interface{}) {
+	*h, v = (*h)[:h.Len()-1], (*h)[h.Len()-1]
+	return
+}
+
+func (h *myHeap) Push(v interface{}) {
+	*h = append(*h, v.(int))
+}
+
+func (h myHeap) verify(t *testing.T, i int) {
+	n := h.Len()
+	j1 := 2*i + 1
+	j2 := 2*i + 2
+	if j1 < n {
+		if h.Less(j1, i) {
+			t.Errorf("heap invariant invalidated [%d] = %d > [%d] = %d", i, h[i], j1, h[j1])
+			return
+		}
+		h.verify(t, j1)
+	}
+	if j2 < n {
+		if h.Less(j2, i) {
+			t.Errorf("heap invariant invalidated [%d] = %d > [%d] = %d", i, h[i], j1, h[j2])
+			return
+		}
+		h.verify(t, j2)
+	}
+}
+
+func TestInit0(t *testing.T) {
+	h := new(myHeap)
+	for i := 20; i > 0; i-- {
+		h.Push(0) // all elements are the same
+	}
+	Init(h)
+	h.verify(t, 0)
+
+	for i := 1; h.Len() > 0; i++ {
+		x := Pop(h).(int)
+		h.verify(t, 0)
+		if x != 0 {
+			t.Errorf("%d.th pop got %d; want %d", i, x, 0)
+		}
+	}
+}
+
+func TestInit1(t *testing.T) {
+	h := new(myHeap)
+	for i := 20; i > 0; i-- {
+		h.Push(i) // all elements are different
+	}
+	Init(h)
+	h.verify(t, 0)
+
+	for i := 1; h.Len() > 0; i++ {
+		x := Pop(h).(int)
+		h.verify(t, 0)
+		if x != i {
+			t.Errorf("%d.th pop got %d; want %d", i, x, i)
+		}
+	}
+}
+
+func Test(t *testing.T) {
+	h := new(myHeap)
+	h.verify(t, 0)
+
+	for i := 20; i > 10; i-- {
+		h.Push(i)
+	}
+	Init(h)
+	h.verify(t, 0)
+
+	for i := 10; i > 0; i-- {
+		Push(h, i)
+		h.verify(t, 0)
+	}
+
+	for i := 1; h.Len() > 0; i++ {
+		x := Pop(h).(int)
+		if i < 20 {
+			Push(h, 20+i)
+		}
+		h.verify(t, 0)
+		if x != i {
+			t.Errorf("%d.th pop got %d; want %d", i, x, i)
+		}
+	}
+}
+
+func TestRemove0(t *testing.T) {
+	h := new(myHeap)
+	for i := 0; i < 10; i++ {
+		h.Push(i)
+	}
+	h.verify(t, 0)
+
+	for h.Len() > 0 {
+		i := h.Len() - 1
+		x := Remove(h, i).(int)
+		if x != i {
+			t.Errorf("Remove(%d) got %d; want %d", i, x, i)
+		}
+		h.verify(t, 0)
+	}
+}
+
+func TestRemove1(t *testing.T) {
+	h := new(myHeap)
+	for i := 0; i < 10; i++ {
+		h.Push(i)
+	}
+	h.verify(t, 0)
+
+	for i := 0; h.Len() > 0; i++ {
+		x := Remove(h, 0).(int)
+		if x != i {
+			t.Errorf("Remove(0) got %d; want %d", x, i)
+		}
+		h.verify(t, 0)
+	}
+}
+
+func TestRemove2(t *testing.T) {
+	N := 10
+
+	h := new(myHeap)
+	for i := 0; i < N; i++ {
+		h.Push(i)
+	}
+	h.verify(t, 0)
+
+	m := make(map[int]bool)
+	for h.Len() > 0 {
+		m[Remove(h, (h.Len()-1)/2).(int)] = true
+		h.verify(t, 0)
+	}
+
+	if len(m) != N {
+		t.Errorf("len(m) = %d; want %d", len(m), N)
+	}
+	for i := 0; i < len(m); i++ {
+		if !m[i] {
+			t.Errorf("m[%d] doesn't exist", i)
+		}
+	}
+}
+
+func BenchmarkDup(b *testing.B) {
+	const n = 10000
+	h := make(myHeap, n)
+	for i := 0; i < b.N; i++ {
+		for j := 0; j < n; j++ {
+			Push(&h, 0) // all elements are the same
+		}
+		for h.Len() > 0 {
+			Pop(&h)
+		}
+	}
+}
+
+func TestFix(t *testing.T) {
+	h := new(myHeap)
+	h.verify(t, 0)
+
+	for i := 200; i > 0; i -= 10 {
+		Push(h, i)
+	}
+	h.verify(t, 0)
+
+	if (*h)[0] != 10 {
+		t.Fatalf("Expected head to be 10, was %d", (*h)[0])
+	}
+	(*h)[0] = 210
+	Fix(h, 0)
+	h.verify(t, 0)
+
+	for i := 100; i > 0; i-- {
+		elem := rand.Intn(h.Len())
+		if i&1 == 0 {
+			(*h)[elem] *= 2
+		} else {
+			(*h)[elem] /= 2
+		}
+		Fix(h, elem)
+		h.verify(t, 0)
+	}
+}