✨ Add JSON marshalling

errorf_test.go

@@ -2,6 +2,7 @@ package errors
 
 import (
 	"errors"
+	"encoding/json"
 	"net/http"
 	"testing"
 
@@ -102,3 +103,24 @@ func (s *ErrorfTestSuite) TestSetStatusOutsideRange() {
 	err.SetStatus(600)
 	s.Assert().Equal(http.StatusPaymentRequired, err.Status())
 }
+
+func (s *ErrorfTestSuite) TestJSON() {
+	var err SettableError = Errorf(http.StatusPaymentRequired, "Hello")
+	s.Assert().NotNil(err)
+
+	m := err.JSON()
+	ma, _ := m.(map[string]any)
+	s.Assert().Equal("Hello", ma["error"])
+	s.Assert().Nil(ma["number"])
+
+	j, _ := json.Marshal(err)
+	s.Assert().Equal(`{"error":"Hello"}`, string(j))
+
+	err.SetField("number",42)
+	m = err.JSON()
+	ma, _ = m.(map[string]any)
+	s.Assert().Equal(42, ma["number"])
+
+	j, _ = json.Marshal(err)
+	s.Assert().Equal(`{"error":"Hello","number":42}`, string(j))
+}