Add unit test

Signed-off-by: Matt Lord <[email protected]>

go/cmd/vtctldclient/cli/json.go

@@ -82,7 +82,8 @@ func MarshalJSONPretty(obj any) ([]byte, error) {
 }
 
 // ConvertToSnakeCase converts a string to snake_case or the keys of a
-// map to snake_case.
+// map to snake_case. This is useful when converting generic JSON data
+// marshalled to a map[string]interface{} for printing.
 func ConvertToSnakeCase(val any) (any, error) {
 	switch val := val.(type) {
 	case string:
@@ -101,16 +102,45 @@ func ConvertToSnakeCase(val any) (any, error) {
 			val[sk] = sv
 		}
 		return val, nil
+	case map[any]interface{}:
+		for k, v := range val {
+			// We need to recurse into the key to support more complex
+			// key types.
+			sk, err := ConvertToSnakeCase(k)
+			if err != nil {
+				return nil, err
+			}
+			// We need to recurse into the map to convert nested maps
+			// to snake_case.
+			sv, err := ConvertToSnakeCase(v)
+			if err != nil {
+				return nil, err
+			}
+			delete(val, k)
+			val[sk] = sv
+		}
+		return val, nil
 	case []interface{}:
 		for i, v := range val {
+			// We need to recurse into the slice to convert nested maps
+			// to snake_case.
 			sv, err := ConvertToSnakeCase(v)
 			if err != nil {
 				return nil, err
 			}
 			val[i] = sv
 		}
 		return val, nil
+	case []string:
+		for i, v := range val {
+			// We need to recurse into the slice to convert nested maps
+			// to snake_case.
+			sk := stats.GetSnakeName(v)
+			val[i] = sk
+		}
+		return val, nil
 	default:
-		return nil, fmt.Errorf("unsupported type %T", val)
+		// No need to do any conversion for things like bool.
+		return val, nil
 	}
 }

go/cmd/vtctldclient/cli/json_test.go

@@ -0,0 +1,128 @@
+/*
+Copyright 2024 The Vitess 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 cli
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestConvertToSnakeCase(t *testing.T) {
+	tests := []struct {
+		name    string
+		val     any
+		want    any
+		wantErr bool
+	}{
+		{
+			name: "string",
+			val:  "MyValIsNotCool",
+			want: "my_val_is_not_cool",
+		},
+		{
+			name: "string slice",
+			val: []string{
+				"MyValIsNotCool",
+				"NeitherIsYours",
+			},
+			want: []string{
+				"my_val_is_not_cool",
+				"neither_is_yours",
+			},
+		},
+		{
+			name: "string map",
+			val: map[string]any{
+				"MyValIsNotCool": "val1",
+				"NeitherIsYours": "val2",
+			},
+			want: map[string]any{
+				"my_val_is_not_cool": "val1",
+				"neither_is_yours":   "val2",
+			},
+		},
+		{
+			name: "string map of slices",
+			val: map[string]any{
+				"MyValIsNotCool": []string{"val1", "val2"},
+				"NeitherIsYours": []string{"val3", "val4"},
+			},
+			want: map[string]any{
+				"my_val_is_not_cool": []string{"val1", "val2"},
+				"neither_is_yours":   []string{"val3", "val4"},
+			},
+		},
+		{
+			name: "string map of slices of string maps",
+			val: map[any]any{
+				"MyValIsNotCool": []any{
+					0: map[any]any{
+						"SubKey1": "val1",
+						"SubKey2": "val2",
+					},
+					1: map[any]any{
+						"SubKey3": "val3",
+						"SubKey4": "val4",
+					},
+				},
+				"NeitherIsYours": []any{
+					0: map[any]any{
+						"SubKey5": "val5",
+						"SubKey6": "val6",
+					},
+					1: map[any]any{
+						"SubKey7": "val7",
+						"SubKey8": "val8",
+					},
+				},
+			},
+			want: map[any]any{
+				"my_val_is_not_cool": []any{
+					0: map[any]any{
+						"sub_key1": "val1",
+						"sub_key2": "val2",
+					},
+					1: map[any]any{
+						"sub_key3": "val3",
+						"sub_key4": "val4",
+					},
+				},
+				"neither_is_yours": []any{
+					0: map[any]any{
+						"sub_key5": "val5",
+						"sub_key6": "val6",
+					},
+					1: map[any]any{
+						"sub_key7": "val7",
+						"sub_key8": "val8",
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ConvertToSnakeCase(tt.val)
+			if (err != nil) != tt.wantErr {
+				require.Fail(t, "unexpted error value", "ConvertToSnakeCase() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			require.EqualValues(t, tt.want, got, "ConvertToSnakeCase() = %v, want %v", got, tt.want)
+		})
+	}
+}