1 files changed, 58 insertions, 0 deletions
diff --git a/src/internal/fuzz/queue_test.go b/src/internal/fuzz/queue_test.go
new file mode 100644
index 00000000000..3b179afb573
--- /dev/null
+++ b/src/internal/fuzz/queue_test.go
@@ -0,0 +1,58 @@
+// Copyright 2021 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 fuzz
+
+import "testing"
+
+func TestQueue(t *testing.T) {
+	// Zero valued queue should have 0 length and capacity.
+	var q queue
+	if n := q.len; n != 0 {
+		t.Fatalf("empty queue has len %d; want 0", n)
+	}
+	if n := q.cap(); n != 0 {
+		t.Fatalf("empty queue has cap %d; want 0", n)
+	}
+
+	// As we add elements, len should grow.
+	N := 32
+	for i := 0; i < N; i++ {
+		q.enqueue(i)
+		if n := q.len; n != i+1 {
+			t.Fatalf("after adding %d elements, queue has len %d", i, n)
+		}
+		if v, ok := q.peek(); !ok {
+			t.Fatalf("couldn't peek after adding %d elements", i)
+		} else if v.(int) != 0 {
+			t.Fatalf("after adding %d elements, peek is %d; want 0", i, v)
+		}
+	}
+
+	// As we remove and add elements, len should shrink and grow.
+	// We should also remove elements in the same order they were added.
+	want := 0
+	for _, r := range []int{1, 2, 3, 5, 8, 13, 21} {
+		s := make([]int, 0, r)
+		for i := 0; i < r; i++ {
+			if got, ok := q.dequeue(); !ok {
+				t.Fatalf("after removing %d of %d elements, could not dequeue", i+1, r)
+			} else if got != want {
+				t.Fatalf("after removing %d of %d elements, got %d; want %d", i+1, r, got, want)
+			} else {
+				s = append(s, got.(int))
+			}
+			want = (want + 1) % N
+			if n := q.len; n != N-i-1 {
+				t.Fatalf("after removing %d of %d elements, len is %d; want %d", i+1, r, n, N-i-1)
+			}
+		}
+		for i, v := range s {
+			q.enqueue(v)
+			if n := q.len; n != N-r+i+1 {
+				t.Fatalf("after adding back %d of %d elements, len is %d; want %d", i+1, r, n, n-r+i+1)
+			}
+		}
+	}
+}