From e3d88d2d7964e5f6a98bf27267f34c2e9f1737d2 Mon Sep 17 00:00:00 2001
From: Jae Kwon <jae@tendermint.com>
Date: Mon, 30 Nov 2015 12:59:05 -0800
Subject: [PATCH] Add ScanRightDeleteRandom test; Add GCRandom test

---
 clist_test.go | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

diff --git a/clist_test.go b/clist_test.go
index 98f94d59a..d5a3f8ed7 100644
--- a/clist_test.go
+++ b/clist_test.go
@@ -1,6 +1,8 @@
 package clist
 
 import (
+	"fmt"
+	"math/rand"
 	"runtime"
 	"testing"
 	"time"
@@ -90,3 +92,122 @@ func TestGCFifo(t *testing.T) {
 			gcCount)
 	}
 }
+
+/*
+This test is quite hacky because it relies on SetFinalizer
+which isn't guaranteed to run at all.
+*/
+func TestGCRandom(t *testing.T) {
+
+	const numElements = 1000000
+	l := New()
+	gcCount := 0
+
+	// SetFinalizer doesn't work well with circular structures,
+	// so we construct a trivial non-circular structure to
+	// track.
+	type value struct {
+		Int int
+	}
+
+	for i := 0; i < numElements; i++ {
+		v := new(value)
+		v.Int = i
+		l.PushBack(v)
+		runtime.SetFinalizer(v, func(v *value) {
+			gcCount += 1
+		})
+	}
+
+	els := make([]*CElement, 0, numElements)
+	for el := l.Front(); el != nil; el = el.Next() {
+		els = append(els, el)
+	}
+
+	for _, i := range rand.Perm(numElements) {
+		el := els[i]
+		l.Remove(el)
+		el = el.Next()
+	}
+
+	runtime.GC()
+	time.Sleep(time.Second * 3)
+
+	if gcCount != numElements {
+		t.Errorf("Expected gcCount to be %v, got %v", numElements,
+			gcCount)
+	}
+}
+
+func TestScanRightDeleteRandom(t *testing.T) {
+
+	const numElements = 10000
+	const numTimes = 10000000
+	const numScanners = 10
+
+	l := New()
+	stop := make(chan struct{})
+
+	els := make([]*CElement, numElements, numElements)
+	for i := 0; i < numElements; i++ {
+		el := l.PushBack(i)
+		els[i] = el
+	}
+
+	// Launch scanner routines that will rapidly iterate over elements.
+	for i := 0; i < numScanners; i++ {
+		go func(scannerID int) {
+			var el *CElement
+			restartCounter := 0
+			counter := 0
+		FOR_LOOP:
+			for {
+				select {
+				case <-stop:
+					fmt.Println("stopped")
+					break FOR_LOOP
+				default:
+				}
+				if el == nil {
+					el = l.FrontWait()
+					restartCounter += 1
+				}
+				el = el.Next()
+				counter += 1
+			}
+			fmt.Printf("Scanner %v restartCounter: %v counter: %v\n", scannerID, restartCounter, counter)
+		}(i)
+	}
+
+	// Remove an element, push back an element.
+	for i := 0; i < numTimes; i++ {
+		// Pick an element to remove
+		rmElIdx := rand.Intn(len(els))
+		rmEl := els[rmElIdx]
+
+		// Remove it
+		l.Remove(rmEl)
+		//fmt.Print(".")
+
+		// Insert a new element
+		newEl := l.PushBack(-1*i - 1)
+		els[rmElIdx] = newEl
+
+		if i%100000 == 0 {
+			fmt.Printf("Pushed %vK elements so far...\n", i/1000)
+		}
+
+	}
+
+	// Stop scanners
+	close(stop)
+	time.Sleep(time.Second * 1)
+
+	// And remove all the elements.
+	for el := l.Front(); el != nil; el = el.Next() {
+		l.Remove(el)
+	}
+	if l.Len() != 0 {
+		t.Fatal("Failed to remove all elements from CList")
+	}
+}