Add plugin worker integration tests for erasure coding (#8450)

* test: add plugin worker integration harness

* test: add erasure coding detection integration tests

* test: add erasure coding execution integration tests

* ci: add plugin worker integration workflow

* test: extend fake volume server for vacuum and balance

* test: expand erasure coding detection topologies

* test: add large erasure coding detection topology

* test: add vacuum plugin worker integration tests

* test: add volume balance plugin worker integration tests

* ci: run plugin worker tests per worker

* fixes

* erasure coding: stop after placement failures

* erasure coding: record hasMore when early stopping

* erasure coding: relax large topology expectations

test/plugin_workers/fake_master.go

@@ -0,0 +1,90 @@
+package pluginworkers
+
+import (
+	"context"
+	"net"
+	"sync"
+
+	"github.com/seaweedfs/seaweedfs/weed/pb"
+	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
+	"google.golang.org/grpc"
+	"google.golang.org/protobuf/proto"
+	"testing"
+)
+
+// MasterServer provides a stub master gRPC service for topology responses.
+type MasterServer struct {
+	master_pb.UnimplementedSeaweedServer
+
+	t *testing.T
+
+	server   *grpc.Server
+	listener net.Listener
+	address  string
+
+	mu       sync.RWMutex
+	response *master_pb.VolumeListResponse
+}
+
+// NewMasterServer starts a stub master server that serves the provided response.
+func NewMasterServer(t *testing.T, response *master_pb.VolumeListResponse) *MasterServer {
+	t.Helper()
+
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("listen master: %v", err)
+	}
+
+	server := pb.NewGrpcServer()
+	ms := &MasterServer{
+		t:        t,
+		server:   server,
+		listener: listener,
+		address:  listener.Addr().String(),
+		response: response,
+	}
+
+	master_pb.RegisterSeaweedServer(server, ms)
+	go func() {
+		_ = server.Serve(listener)
+	}()
+
+	t.Cleanup(func() {
+		ms.Shutdown()
+	})
+
+	return ms
+}
+
+// Address returns the gRPC address of the master server.
+func (m *MasterServer) Address() string {
+	return m.address
+}
+
+// SetVolumeListResponse updates the response served by VolumeList.
+func (m *MasterServer) SetVolumeListResponse(response *master_pb.VolumeListResponse) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.response = response
+}
+
+// VolumeList returns the configured topology response.
+func (m *MasterServer) VolumeList(ctx context.Context, req *master_pb.VolumeListRequest) (*master_pb.VolumeListResponse, error) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	if m.response == nil {
+		return &master_pb.VolumeListResponse{}, nil
+	}
+	return proto.Clone(m.response).(*master_pb.VolumeListResponse), nil
+}
+
+// Shutdown stops the master gRPC server.
+func (m *MasterServer) Shutdown() {
+	if m.server != nil {
+		m.server.GracefulStop()
+	}
+	if m.listener != nil {
+		_ = m.listener.Close()
+	}
+}