Add package grumble/sessionpool for improved session ID reuse.

pkg/sessionpool/sessionpool_test.go

@@ -0,0 +1,51 @@
+package sessionpool
+
+import (
+	"math"
+	"testing"
+)
+
+func TestReclaim(t *testing.T) {
+	pool := New()
+	id := pool.Get()
+	if id != 0 {
+		t.Errorf("Got %v, expected 0 (first time)", id)
+	}
+
+	pool.Reclaim(0)
+
+	id = pool.Get()
+	if id != 0 {
+		t.Errorf("Got %v, expected 0 (second time)", id)
+	}
+
+	id = pool.Get()
+	if id != 1 {
+		t.Errorf("Got %v, expected 1", id)
+	}
+}
+
+func TestDepletion(t *testing.T) {
+	defer func() {
+		r := recover()
+		if r != "SessionPool depleted" {
+			t.Errorf("Expected depletion panic")
+		}
+	}()
+	pool := New()
+	pool.next = math.MaxUint32
+	pool.Get()
+}
+
+func TestUseTracking(t *testing.T) {
+	defer func() {
+		r := recover()
+		if r != "Attempt to reclaim invalid session ID" {
+			t.Errorf("Expected reclamation panic")
+		}
+	}()
+
+	pool := New()
+	pool.EnableUseTracking()
+	pool.Reclaim(42)
+}