diff --git a/plugin/plugin_test.go b/plugin/plugin_test.go
new file mode 100644
index 000000000..b79e054be
--- /dev/null
+++ b/plugin/plugin_test.go
@@ -0,0 +1,385 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package plugin
+
+import (
+	"testing"
+
+	"github.com/containerd/containerd/services"
+)
+
+func registerClear() {
+	register.Lock()
+	defer register.Unlock()
+	register.r = nil
+}
+
+func mockPluginFilter(*Registration) bool {
+	return false
+}
+
+var tasksServiceRequires = []Type{
+	RuntimePlugin,
+	RuntimePluginV2,
+	MetadataPlugin,
+	TaskMonitorPlugin,
+}
+
+// TestContainerdPlugin tests the logic of Graph, use the containerd's plugin
+func TestContainerdPlugin(t *testing.T) {
+	registerClear()
+	Register(&Registration{
+		Type: TaskMonitorPlugin,
+		ID:   "cgroups",
+	})
+	Register(&Registration{
+		Type:     ServicePlugin,
+		ID:       services.TasksService,
+		Requires: tasksServiceRequires,
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.IntrospectionService,
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.NamespacesService,
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "namespaces",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "content",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "containers",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.ContainersService,
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "events",
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "leases",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.LeasesService,
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "diff",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.DiffService,
+		Requires: []Type{
+			DiffPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.SnapshotsService,
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "snapshots",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "version",
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "images",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GCPlugin,
+		ID:   "scheduler",
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: RuntimePluginV2,
+		ID:   "task",
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "tasks",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type:     GRPCPlugin,
+		ID:       "introspection",
+		Requires: []Type{"*"},
+	})
+	Register(&Registration{
+		Type: ServicePlugin,
+		ID:   services.ContentService,
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "healthcheck",
+	})
+	Register(&Registration{
+		Type: InternalPlugin,
+		ID:   "opt",
+	})
+	Register(&Registration{
+		Type: GRPCPlugin,
+		ID:   "cri",
+		Requires: []Type{
+			ServicePlugin,
+		},
+	})
+	Register(&Registration{
+		Type: RuntimePlugin,
+		ID:   "linux",
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: InternalPlugin,
+		Requires: []Type{
+			ServicePlugin,
+		},
+		ID: "restart",
+	})
+	Register(&Registration{
+		Type: DiffPlugin,
+		ID:   "walking",
+		Requires: []Type{
+			MetadataPlugin,
+		},
+	})
+	Register(&Registration{
+		Type: SnapshotPlugin,
+		ID:   "native",
+	})
+	Register(&Registration{
+		Type: SnapshotPlugin,
+		ID:   "overlayfs",
+	})
+	Register(&Registration{
+		Type: ContentPlugin,
+		ID:   "content",
+	})
+	Register(&Registration{
+		Type: MetadataPlugin,
+		ID:   "bolt",
+		Requires: []Type{
+			ContentPlugin,
+			SnapshotPlugin,
+		},
+	})
+
+	ordered := Graph(mockPluginFilter)
+	expectedURI := []string{
+		"io.containerd.monitor.v1.cgroups",
+		"io.containerd.content.v1.content",
+		"io.containerd.snapshotter.v1.native",
+		"io.containerd.snapshotter.v1.overlayfs",
+		"io.containerd.metadata.v1.bolt",
+		"io.containerd.runtime.v1.linux",
+		"io.containerd.runtime.v2.task",
+		"io.containerd.service.v1.tasks-service",
+		"io.containerd.service.v1.introspection-service",
+		"io.containerd.service.v1.namespaces-service",
+		"io.containerd.service.v1.containers-service",
+		"io.containerd.service.v1.leases-service",
+		"io.containerd.differ.v1.walking",
+		"io.containerd.service.v1.diff-service",
+		"io.containerd.service.v1.snapshots-service",
+		"io.containerd.service.v1.content-service",
+		"io.containerd.grpc.v1.namespaces",
+		"io.containerd.grpc.v1.content",
+		"io.containerd.grpc.v1.containers",
+		"io.containerd.grpc.v1.events",
+		"io.containerd.grpc.v1.leases",
+		"io.containerd.grpc.v1.diff",
+		"io.containerd.grpc.v1.snapshots",
+		"io.containerd.grpc.v1.version",
+		"io.containerd.grpc.v1.images",
+		"io.containerd.gc.v1.scheduler",
+		"io.containerd.grpc.v1.tasks",
+		"io.containerd.grpc.v1.healthcheck",
+		"io.containerd.internal.v1.opt",
+		"io.containerd.grpc.v1.cri",
+		"io.containerd.internal.v1.restart",
+		"io.containerd.grpc.v1.introspection",
+	}
+	cmpOrdered(t, ordered, expectedURI)
+}
+
+func cmpOrdered(t *testing.T, ordered []*Registration, expectedURI []string) {
+	if len(ordered) != len(expectedURI) {
+		t.Fatalf("ordered compare failed, %d != %d", len(ordered), len(expectedURI))
+	}
+	for i := range ordered {
+		if ordered[i].URI() != expectedURI[i] {
+			t.Fatalf("graph failed, expected: %s, but return: %s", expectedURI[i], ordered[i].URI())
+		}
+	}
+}
+
+// TestPluginGraph tests the logic of Graph
+func TestPluginGraph(t *testing.T) {
+	for _, testcase := range []struct {
+		input       []*Registration
+		expectedURI []string
+	}{
+		// test requires *
+		{
+			input: []*Registration{
+				{
+					Type: "grpc",
+					ID:   "introspection",
+					Requires: []Type{
+						"*",
+					},
+				},
+				{
+					Type: "service",
+					ID:   "container",
+				},
+			},
+			expectedURI: []string{
+				"service.container",
+				"grpc.introspection",
+			},
+		},
+		// test requires
+		{
+			input: []*Registration{
+				{
+					Type: "service",
+					ID:   "container",
+					Requires: []Type{
+						"metadata",
+					},
+				},
+				{
+					Type: "metadata",
+					ID:   "bolt",
+				},
+			},
+			expectedURI: []string{
+				"metadata.bolt",
+				"service.container",
+			},
+		},
+		{
+			input: []*Registration{
+				{
+					Type: "metadata",
+					ID:   "bolt",
+					Requires: []Type{
+						"content",
+						"snapshotter",
+					},
+				},
+				{
+					Type: "snapshotter",
+					ID:   "overlayfs",
+				},
+				{
+					Type: "content",
+					ID:   "content",
+				},
+			},
+			expectedURI: []string{
+				"content.content",
+				"snapshotter.overlayfs",
+				"metadata.bolt",
+			},
+		},
+		// test disable
+		{
+			input: []*Registration{
+				{
+					Type: "content",
+					ID:   "content",
+				},
+				{
+					Type:    "disable",
+					ID:      "disable",
+					Disable: true,
+				},
+			},
+			expectedURI: []string{
+				"content.content",
+			},
+		},
+	} {
+		registerClear()
+		for _, in := range testcase.input {
+			Register(in)
+		}
+		ordered := Graph(mockPluginFilter)
+		cmpOrdered(t, ordered, testcase.expectedURI)
+	}
+}