Added correct handling of schema example rendering

reported in https://github.com/pb33f/wiretap/issues/84

Signed-off-by: quobix <dave@quobix.com>

index/spec_index_test.go

@@ -453,7 +453,7 @@ func TestSpecIndex_BaseURLError(t *testing.T) {
 	files := remoteFS.GetFiles()
 	fileLen := len(files)
 	assert.Equal(t, 0, fileLen)
-	assert.GreaterOrEqual(t, len(remoteFS.GetErrors()), 200)
+	assert.GreaterOrEqual(t, len(remoteFS.GetErrors()), 155)
 }
 
 func TestSpecIndex_k8s(t *testing.T) {

renderer/mock_generator.go

@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"reflect"
+	"strconv"
 
 	highbase "github.com/pb33f/libopenapi/datamodel/high/base"
 	"github.com/pb33f/libopenapi/orderedmap"
@@ -154,6 +155,27 @@ func (mg *MockGenerator) GenerateMock(mock any, name string) ([]byte, error) {
 	}
 
 	if schemaValue != nil {
+
+		// now lets check the schema for `Examples` and `Example` fields.
+		if schemaValue.Examples != nil {
+			if name != "" {
+				// try and convert the example to an integer
+				if i, err := strconv.Atoi(name); err == nil {
+					if i < len(schemaValue.Examples) {
+						return mg.renderMock(schemaValue.Examples[i]), nil
+					}
+				}
+			}
+			// if the name is empty, just return the first example
+			return mg.renderMock(schemaValue.Examples[0]), nil
+		}
+
+		// check the example field
+		if schemaValue.Example != nil {
+			return mg.renderMock(schemaValue.Example), nil
+		}
+
+		// render the schema as our last hope.
 		renderMap := mg.renderer.RenderSchema(schemaValue)
 		if renderMap != nil {
 			return mg.renderMock(renderMap), nil

renderer/mock_generator_test.go

@@ -323,3 +323,94 @@ func TestMockGenerator_GenerateMock_YamlNode_Nil(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, "hello", strings.TrimSpace(string(mock)))
 }
+
+func TestMockGenerator_GenerateJSONMock_Object_SchemaExamples(t *testing.T) {
+
+	yml := `type: object
+examples:
+  - name: happy days
+    description: a terrible show from a time that never existed.
+  - name: robocop
+    description: perhaps the best cyberpunk movie ever made.
+properties:
+  name:
+    type: string
+    example: nameExample
+  description:
+    type: string
+    example: descriptionExample`
+
+	fake := createFakeMock(yml, nil, nil)
+	mg := NewMockGenerator(YAML)
+	mock, err := mg.GenerateMock(fake, "")
+	assert.NoError(t, err)
+
+	// re-serialize back into a map and check the values
+	var m map[string]any
+	err = yaml.Unmarshal(mock, &m)
+	assert.NoError(t, err)
+
+	assert.Len(t, m, 2)
+	assert.Equal(t, "happy days", m["name"].(string))
+	assert.Equal(t, "a terrible show from a time that never existed.", m["description"].(string))
+}
+
+func TestMockGenerator_GenerateJSONMock_Object_SchemaExamples_Preferred(t *testing.T) {
+
+	yml := `type: object
+examples:
+  - name: happy days
+    description: a terrible show from a time that never existed.
+  - name: robocop
+    description: perhaps the best cyberpunk movie ever made.
+properties:
+  name:
+    type: string
+    example: nameExample
+  description:
+    type: string
+    example: descriptionExample`
+
+	fake := createFakeMock(yml, nil, nil)
+	mg := NewMockGenerator(YAML)
+	mock, err := mg.GenerateMock(fake, "1")
+	assert.NoError(t, err)
+
+	// re-serialize back into a map and check the values
+	var m map[string]any
+	err = yaml.Unmarshal(mock, &m)
+	assert.NoError(t, err)
+
+	assert.Len(t, m, 2)
+	assert.Equal(t, "robocop", m["name"].(string))
+	assert.Equal(t, "perhaps the best cyberpunk movie ever made.", m["description"].(string))
+}
+
+func TestMockGenerator_GenerateJSONMock_Object_SchemaExample(t *testing.T) {
+
+	yml := `type: object
+example:
+  name: robocop
+  description: perhaps the best cyberpunk movie ever made.
+properties:
+  name:
+    type: string
+    example: nameExample
+  description:
+    type: string
+    example: descriptionExample`
+
+	fake := createFakeMock(yml, nil, nil)
+	mg := NewMockGenerator(YAML)
+	mock, err := mg.GenerateMock(fake, "")
+	assert.NoError(t, err)
+
+	// re-serialize back into a map and check the values
+	var m map[string]any
+	err = yaml.Unmarshal(mock, &m)
+	assert.NoError(t, err)
+
+	assert.Len(t, m, 2)
+	assert.Equal(t, "robocop", m["name"].(string))
+	assert.Equal(t, "perhaps the best cyberpunk movie ever made.", m["description"].(string))
+}