From bb20704c3451fd2e9669ececabcda159fbce69fd Mon Sep 17 00:00:00 2001
From: Spencer Reeves <spencer@apt304.io>
Date: Sat, 14 May 2022 14:05:40 -0700
Subject: [PATCH] test for thread.pool

---
 thread/pool.go      | 19 ++++++++++++-------
 thread/pool_test.go | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 7 deletions(-)

diff --git a/thread/pool.go b/thread/pool.go
index 0c5f01c..9d0cfa6 100644
--- a/thread/pool.go
+++ b/thread/pool.go
@@ -10,6 +10,7 @@ type Pool[K any] struct {
 	Consume         func(elem *K) error
 	OnError         func(elem *K, e error)
 	Closed          bool
+	closeCh         chan struct{}
 	waitGroup       sync.WaitGroup
 	workers         []*Thread
 }
@@ -21,31 +22,35 @@ func NewPool[K any](count int, consumerChan chan K, consumerFn func(elem *K) err
 		Consume:         consumerFn,
 		OnError:         onError,
 		Closed:          false,
+		closeCh:         make(chan struct{}),
 	}
 
-	p.waitGroup.Add(count)
 	for i := 0; i < count; i++ {
-		p.workers = append(p.workers, Consumer[K](&p.waitGroup, consumerChan, consumerFn, onError))
+		p.workers = append(p.workers, Consumer[K](&p.waitGroup, p.closeCh, consumerChan, consumerFn, onError))
 	}
 
 	return &p
 }
 
-// Close Has side effects! Closes the channel and optionally waits for threads to indicate they have closed.
 func (p *Pool[K]) Close(block bool) error {
-	if !p.Closed {
-		close(p.ConsumerChannel)
+	if p.Closed {
+		return nil
+	} else {
+		for i := 0; i < p.Count; i++ {
+			p.closeCh <- struct{}{}
+		}
 	}
 
-	p.Closed = true
 	if block {
 		p.waitGroup.Wait()
+		close(p.closeCh)
 	}
 
+	p.Closed = true
 	return nil
 }
 
-func (p *Pool[K]) Metrics(aggregated bool) []*Metric {
+func (p *Pool[K]) Metrics() []*Metric {
 	var metrics []*Metric
 	for _, w := range p.workers {
 		metrics = append(metrics, w.Metrics)
diff --git a/thread/pool_test.go b/thread/pool_test.go
index e69de29..3de67a5 100644
--- a/thread/pool_test.go
+++ b/thread/pool_test.go
@@ -0,0 +1,44 @@
+package thread_test
+
+import (
+	"github.com/spencerreeves/snippets/thread"
+	"testing"
+	"time"
+)
+
+func TestNewPool(t *testing.T) {
+	cnt, errs, ch := 0, 0, make(chan int, 1)
+
+	// Verify we can create a pool
+	p := thread.NewPool[int](2, ch, incFn(&cnt), errCntFn(&errs))
+
+	// Verify pool consumes data
+	ch <- 1
+	ch <- 1
+	time.Sleep(time.Millisecond)
+	if cnt != 2 {
+		t.Error("invalid count")
+	}
+
+	// Verify all threads are closed when we close a pool
+	if err := p.Close(true); err != nil || !p.Closed {
+		t.Error("pool failed to close")
+	}
+
+	ch <- 1
+	if cnt != 2 {
+		t.Error("pool failed to close, consuming channel")
+		t.Fail()
+	}
+
+	// Verify the metrics
+	processedCount, processedErrs := 0, 0
+	for _, m := range p.Metrics() {
+		processedCount += m.ProcessedCount
+		processedErrs += m.ErrorCount
+	}
+	if processedCount != cnt || processedErrs != errs {
+		t.Error("consume and error callbacks failed")
+		t.Fail()
+	}
+}