test(cluster): cover weighted node pool selection

NewNodePool/Get had no tests. Covers capability-slot miss, preferred-
node override, and weight-based selection.

Authored By: TDvorak <info@tdvorak.dev>

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

pkg/cluster/pool_test.go

@@ -0,0 +1,88 @@
+package cluster
+
+import (
+	"context"
+	"errors"
+	"path/filepath"
+	"testing"
+
+	"github.com/cloudreve/Cloudreve/v4/ent"
+	"github.com/cloudreve/Cloudreve/v4/ent/enttest"
+	"github.com/cloudreve/Cloudreve/v4/ent/node"
+	"github.com/cloudreve/Cloudreve/v4/inventory"
+	"github.com/cloudreve/Cloudreve/v4/inventory/types"
+	"github.com/cloudreve/Cloudreve/v4/pkg/boolset"
+	"github.com/cloudreve/Cloudreve/v4/pkg/conf"
+	"github.com/cloudreve/Cloudreve/v4/pkg/logging"
+	"github.com/cloudreve/Cloudreve/v4/pkg/setting"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type stubSettings struct {
+	setting.Provider
+}
+
+func capsOf(bits ...types.NodeCapability) *boolset.BooleanSet {
+	b := &boolset.BooleanSet{}
+	for _, c := range bits {
+		boolset.Set(int(c), true, b)
+	}
+	return b
+}
+
+func newPoolFixture(t *testing.T) (*ent.Client, NodePool, context.Context) {
+	t.Helper()
+	ctx := context.Background()
+	client := enttest.Open(t, "sqlite3", "file:ent?mode=memory&_fk=1")
+	t.Cleanup(func() { client.Close() })
+
+	logger := logging.NewConsoleLogger(logging.LevelError)
+	cfg, err := conf.NewIniConfigProvider(filepath.Join(t.TempDir(), "conf.ini"), logger)
+	require.NoError(t, err)
+
+	pool, err := NewNodePool(ctx, logger, cfg, &stubSettings{}, inventory.NewNodeClient(client))
+	require.NoError(t, err)
+	return client, pool, ctx
+}
+
+func TestWeightedNodePoolGet(t *testing.T) {
+	a := assert.New(t)
+	client, pool, ctx := newPoolFixture(t)
+
+	n1 := client.Node.Create().
+		SetName("n1").SetType(node.TypeMaster).SetStatus(node.StatusActive).
+		SetServer("http://n1").SetCapabilities(capsOf(types.NodeCapabilityRemoteDownload)).
+		SetWeight(10).SaveX(ctx)
+	client.Node.Create().
+		SetName("n2").SetType(node.TypeMaster).SetStatus(node.StatusActive).
+		SetServer("http://n2").SetCapabilities(capsOf(types.NodeCapabilityRemoteDownload)).
+		SetWeight(1).SaveX(ctx)
+
+	pool.(*weightedNodePool).Upsert(ctx, n1)
+	// Upsert requires a full refresh — rebuild pool from the seeded DB instead.
+	pool, err := NewNodePool(ctx, logging.NewConsoleLogger(logging.LevelError), pool.(*weightedNodePool).conf, &stubSettings{}, inventory.NewNodeClient(client))
+	require.NoError(t, err)
+
+	// Capability with no matching nodes errors.
+	_, err = pool.Get(ctx, types.NodeCapabilityCreateArchive, 0)
+	a.True(errors.Is(err, ErrNoAvailableNode))
+
+	// Preferred node wins regardless of weight.
+	selected, err := pool.Get(ctx, types.NodeCapabilityRemoteDownload, n1.ID)
+	require.NoError(t, err)
+	a.Equal(n1.ID, selected.ID())
+
+	// Without preference, the heavier node wins the first pick.
+	selected, err = pool.Get(ctx, types.NodeCapabilityRemoteDownload, 0)
+	require.NoError(t, err)
+	a.Equal(n1.ID, selected.ID())
+}
+
+func TestWeightedNodePoolGetUnknownCapability(t *testing.T) {
+	a := assert.New(t)
+	_, pool, ctx := newPoolFixture(t)
+
+	_, err := pool.Get(ctx, types.NodeCapabilityRemoteDownload, 0)
+	a.True(errors.Is(err, ErrNoAvailableNode))
+}