Add reference to ygnmi in README and go:generate for gogen's integr…

…ation test (#963)

* Add reference to ygnmi in README

* add reference to example code

* add another test to clarify that module prefix not needed during unmarshal of identities

README.md

@@ -186,6 +186,24 @@ if err := oc.Unmarshal([]byte(json), loadd); err != nil {
 
 Currently, only the `RFC7951` format of JSON is supported for unmarshalling, the `Internal` format supported by ygot is not yet supported.
 
+### Interacting with gNMI Server(s) via ygot GoStructs
+
+While ygot provides Go types for structuring YANG data, the process of
+interacting with a gNMI server is often cumbersome:
+
+1. Marshalling a GoStruct to JSON.
+2. Creating a gNMI `SetRequest` or `SubscribeRequest` object.
+3. Processing the `SubscribeResponse` stream and accumulating per-path errors.
+4. Unmarshalling the response from scalar protobufs or JSON to a GoStruct.
+
+If this applies to you, refer to [ygnmi](https://github.com/openconfig/ygnmi)
+for a ygot-based tool that generates not only the same ygot GoStructs, but also
+helpers for each GoStruct and leaf [example
+code](https://github.com/openconfig/ygnmi/blob/3863fe4d5757372579da234636b064f933205ab8/ygnmi/example_test.go#L266).
+ygnmi is used by [Ondatra](https://github.com/openconfig/ondatra) to create its
+[gNMI test library](https://github.com/openconfig/ondatra/tree/main/gnmi) used
+in [featureprofiles](This too://github.com/openconfig/featureprofiles).
+
 ## For Developers
  * [Contributing](CONTRIBUTING.md) - how to contribute to ygot.
  * [Contributors](docs/CONTRIBUTORS.md) - Folks who have contributed to ygot, thanks very much!

gogen/codegen_test.go

@@ -28,6 +28,8 @@ const (
 
 var updateGolden = flag.Bool("update_golden", false, "Update golden files")
 
+//go:generate go test -run TestSimpleStructs -args -update_golden
+
 // yangTestCase describs a test case for which code generation is performed
 // through Goyang's API, it provides the input set of parameters in a way that
 // can be reused across tests.
@@ -1183,6 +1185,12 @@ func TestSimpleStructs(t *testing.T) {
 			}
 
 			if tt.wantSchemaFile != "" {
+				if *updateGolden {
+					if err := os.WriteFile(tt.wantSchemaFile, []byte(string(gotGeneratedCode.RawJSONSchema)), 0644); err != nil {
+						panic(err)
+					}
+				}
+
 				wantSchema, rferr := os.ReadFile(tt.wantSchemaFile)
 				if rferr != nil {
 					t.Fatalf("%s: os.ReadFile(%q) error: %v", tt.name, tt.wantSchemaFile, rferr)
@@ -1199,6 +1207,12 @@ func TestSimpleStructs(t *testing.T) {
 				}
 			}
 
+			if *updateGolden {
+				if err := os.WriteFile(tt.wantStructsCodeFile, []byte(gotCode), 0644); err != nil {
+					t.Fatal(err)
+				}
+			}
+
 			wantCodeBytes, rferr := os.ReadFile(tt.wantStructsCodeFile)
 			if rferr != nil {
 				t.Fatalf("%s: os.ReadFile(%q) error: %v", tt.name, tt.wantStructsCodeFile, rferr)
@@ -1207,11 +1221,6 @@ func TestSimpleStructs(t *testing.T) {
 			wantCode := string(wantCodeBytes)
 
 			if gotCode != wantCode {
-				if *updateGolden {
-					if err := os.WriteFile(tt.wantStructsCodeFile, []byte(gotCode), 0644); err != nil {
-						t.Fatal(err)
-					}
-				}
 				// Use difflib to generate a unified diff between the
 				// two code snippets such that this is simpler to debug
 				// in the test output.

gogen/testdata/schema/openconfig-options-compress-fakeroot-schema.json

@@ -363,4 +363,4 @@
         "schemapath": "/",
         "structname": "Device"
     }
-}
+}

gogen/testdata/schema/openconfig-options-compress-schema.json

@@ -361,4 +361,4 @@
         "isCompressedSchema": true,
         "isFakeRoot": true
     }
-}
+}

gogen/testdata/schema/openconfig-options-nocompress-fakeroot-schema.json

@@ -359,4 +359,4 @@
         "schemapath": "/",
         "structname": "Device"
     }
-}
+}

gogen/testdata/schema/openconfig-options-nocompress-schema.json

@@ -357,4 +357,4 @@
     "Annotation": {
         "isFakeRoot": true
     }
-}
+}

ytypes/schema_tests/set_test.go

@@ -131,6 +131,84 @@ func TestSet(t *testing.T) {
 			},
 			Data: []exampleoc.RoutingPolicy_PolicyDefinition_Statement_Actions_BgpActions_SetCommunity_Inline_Communities_Union{exampleoc.BgpTypes_BGP_WELL_KNOWN_STD_COMMUNITY_NO_ADVERTISE},
 		},
+	}, {
+		desc:     "set-on-union-with-invalid-string-but-valid-enum-no-module",
+		inSchema: mustSchema(exampleoc.Schema),
+		inPath: &gpb.Path{
+			Elem: []*gpb.PathElem{{
+				Name: "routing-policy",
+			}, {
+				Name: "policy-definitions",
+			}, {
+				Name: "policy-definition",
+				Key: map[string]string{
+					"name": "test",
+				},
+			}, {
+				Name: "statements",
+			}, {
+				Name: "statement",
+				Key: map[string]string{
+					"name": "test-stmt",
+				},
+			}, {
+				Name: "actions",
+			}, {
+				Name: "bgp-actions",
+			}, {
+				Name: "set-community",
+			}, {
+				Name: "inline",
+			}, {
+				Name: "config",
+			}, {
+				Name: "communities",
+			}},
+		},
+		inValue: &gpb.TypedValue{
+			Value: &gpb.TypedValue_LeaflistVal{
+				LeaflistVal: &gpb.ScalarArray{
+					Element: []*gpb.TypedValue{{
+						Value: &gpb.TypedValue_StringVal{StringVal: "NO_ADVERTISE"},
+					}},
+				},
+			},
+		},
+		inOpts: []ytypes.SetNodeOpt{&ytypes.InitMissingElements{}},
+		wantNode: &ytypes.TreeNode{
+			Path: &gpb.Path{
+				Elem: []*gpb.PathElem{{
+					Name: "routing-policy",
+				}, {
+					Name: "policy-definitions",
+				}, {
+					Name: "policy-definition",
+					Key: map[string]string{
+						"name": "test",
+					},
+				}, {
+					Name: "statements",
+				}, {
+					Name: "statement",
+					Key: map[string]string{
+						"name": "test-stmt",
+					},
+				}, {
+					Name: "actions",
+				}, {
+					Name: "bgp-actions",
+				}, {
+					Name: "set-community",
+				}, {
+					Name: "inline",
+				}, {
+					Name: "config",
+				}, {
+					Name: "communities",
+				}},
+			},
+			Data: []exampleoc.RoutingPolicy_PolicyDefinition_Statement_Actions_BgpActions_SetCommunity_Inline_Communities_Union{exampleoc.BgpTypes_BGP_WELL_KNOWN_STD_COMMUNITY_NO_ADVERTISE},
+		},
 	}, {
 		desc:     "set-on-union-with-invalid-string-but-valid-enum-json-container",
 		inSchema: mustSchema(opstateoc.Schema),