Examples validation (#592)

Co-authored-by: Pierre Fenoll <pierrefenoll@gmail.com>

Author: danicc097

openapi3/components.go

@@ -99,7 +99,7 @@ func (components *Components) Validate(ctx context.Context) (err error) {
 			return
 		}
 		if err = v.Validate(ctx); err != nil {
-			return
+			return fmt.Errorf("%s: %s", k, err)
 		}
 	}
 

openapi3/example.go

@@ -2,6 +2,7 @@ package openapi3
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"github.com/go-openapi/jsonpointer"
@@ -55,5 +56,12 @@ func (example *Example) UnmarshalJSON(data []byte) error {
 
 // Validate returns an error if Example does not comply with the OpenAPI spec.
 func (example *Example) Validate(ctx context.Context) error {
-	return nil // TODO
+	if example.Value != nil && example.ExternalValue != "" {
+		return errors.New("value and externalValue are mutually exclusive")
+	}
+	if example.Value == nil && example.ExternalValue == "" {
+		return errors.New("example has no value or externalValue field")
+	}
+
+	return nil
 }

openapi3/example_validation.go

@@ -0,0 +1,5 @@
+package openapi3
+
+func validateExampleValue(input interface{}, schema *Schema) error {
+	return schema.VisitJSON(input, MultiErrors())
+}