fix APIError to always report errors

* add unit-test

Signed-off-by: elv-gilles <gilles.gaillard@eluv.io>

client_response.go

@@ -15,10 +15,9 @@
 package runtime
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
-
-	"encoding/json"
 )
 
 // A ClientResponse represents a client response
@@ -61,13 +60,18 @@ type APIError struct {
 	Code          int
 }
 
-func (a *APIError) Error() string {
-	resp, _ := json.Marshal(a.Response)
-	return fmt.Sprintf("%s (status %d): %s", a.OperationName, a.Code, resp)
+func (o *APIError) Error() string {
+	var resp []byte
+	if err, ok := o.Response.(error); ok {
+		resp = []byte("'" + err.Error() + "'")
+	} else {
+		resp, _ = json.Marshal(o.Response)
+	}
+	return fmt.Sprintf("%s (status %d): %s", o.OperationName, o.Code, resp)
 }
 
-func (a *APIError) String() string {
-	return a.Error()
+func (o *APIError) String() string {
+	return o.Error()
 }
 
 // IsSuccess returns true when this elapse o k response returns a 2xx status code

client_response_test.go

@@ -16,8 +16,11 @@ package runtime
 
 import (
 	"bytes"
+	"errors"
 	"io"
+	"io/fs"
 	"io/ioutil"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -61,3 +64,27 @@ func TestResponseReaderFunc(t *testing.T) {
 	assert.Equal(t, "the header", actual.Header)
 	assert.Equal(t, 490, actual.Code)
 }
+
+func TestResponseReaderFuncError(t *testing.T) {
+	reader := ClientResponseReaderFunc(func(r ClientResponse, _ Consumer) (interface{}, error) {
+		_, _ = ioutil.ReadAll(r.Body())
+		return nil, NewAPIError("fake", errors.New("writer closed"), 490)
+	})
+	_, err := reader.ReadResponse(response{}, nil)
+	assert.NotNil(t, err)
+	assert.True(t, strings.Contains(err.Error(), "writer closed"), err.Error())
+
+	reader = func(r ClientResponse, _ Consumer) (interface{}, error) {
+		_, _ = ioutil.ReadAll(r.Body())
+		err := &fs.PathError{
+			Op:   "write",
+			Path: "path/to/fake",
+			Err:  fs.ErrClosed,
+		}
+		return nil, NewAPIError("fake", err, 200)
+	}
+	_, err = reader.ReadResponse(response{}, nil)
+	assert.NotNil(t, err)
+	assert.True(t, strings.Contains(err.Error(), "file already closed"), err.Error())
+
+}