Improve worker task handling and add pool tests

- Changed the worker task channel to be buffered to prevent blocking when submitting tasks.
- Added a new test file, pool_test.go, to test the Submit function of the pool.
- The test ensures that all tasks are executed and that there are no running workers left after all tasks are done.

Signed-off-by: Daniel Hu <tao.hu@merico.dev>

pool.go

@@ -14,7 +14,7 @@ type Pool struct {
 	// lock represents a mutex to protect the workers slice
 	lock sync.Mutex
 	// cond represents a condition variable to manage the pool
-	cond     *sync.Cond
+	cond *sync.Cond
 }
 
 func NewPool(capacity int) *Pool {
@@ -38,7 +38,7 @@ func (p *Pool) Submit(task Task) {
 	if worker == nil {
 		worker = &Worker{
 			pool: p,
-			task: make(chan Task),
+			task: make(chan Task, 1),
 		}
 	}
 	worker.task <- task

pool_test.go

@@ -0,0 +1,27 @@
+package gopool
+
+import (
+	"sync"
+	"testing"
+)
+
+func TestSubmit(t *testing.T) {
+	var wg sync.WaitGroup
+	p := NewPool(10)
+
+	for i := 0; i < 20; i++ {
+		wg.Add(1)
+		taskNum := i // Capture the task number
+		task := func() {
+			t.Logf("Executing task %d\n", taskNum)
+			defer wg.Done()
+		}
+		p.Submit(task)
+	}
+
+	wg.Wait()
+
+	if p.Running() != 0 {
+		t.Errorf("Expected running workers to be 0, but got %d", p.Running())
+	}
+}