Merge pull request #245 from manisharma/panic-fix

method.IsNil() panics and the actual error is never returned

CHANGELOG.md

@@ -11,6 +11,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+## [1.0.1] - 2023-11-24
+
+### Changed
+
+- Fixed a bug where page iterator would panic if it couldn't find the GetValue method on the collection.
+
 ## [1.0.0] - 2023-05-04
 
 ### Changed

page_iterator.go

@@ -216,7 +216,7 @@ func convertToPage[T interface{}](response interface{}) (PageResult[T], error) {
 	}
 
 	method := reflect.ValueOf(response).MethodByName("GetValue")
-	if method.IsNil() {
+	if method.Kind() == reflect.Invalid {
 		return page, errors.New("value property missing in response object")
 	}
 	value := method.Call(nil)[0]

page_iterator_test.go

@@ -261,3 +261,132 @@ func buildGraphResponse() *internal.UsersResponse {
 
 	return res
 }
+
+func Test_convertToPage(t *testing.T) {
+	type args struct {
+		response interface{}
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    PageResult[validTestStruct]
+		wantErr bool
+	}{
+		{
+			name: "should pass",
+			args: args{
+				response: &validTestStruct{
+					obj: []validTestStruct{
+						{
+							obj: []validTestStruct{
+								{
+									obj: []validTestStruct{},
+								},
+							},
+						},
+					}},
+			},
+			want: PageResult[validTestStruct]{
+				oDataNextLink:  nil,
+				oDataDeltaLink: nil,
+				value: []validTestStruct{
+					{
+						obj: []validTestStruct{
+							{
+								obj: []validTestStruct{},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "should return error 'saying response cannot be nil' for nil response",
+			args: args{
+				response: nil,
+			},
+			want: PageResult[validTestStruct]{
+				oDataNextLink:  nil,
+				oDataDeltaLink: nil,
+				value:          nil,
+			},
+			wantErr: true,
+		},
+		{
+			name: "should return error 'value property missing in response object' for missing 'GetValue' method",
+			args: args{
+				response: &invalidTestStruct{
+					obj: []invalidTestStruct{
+						{
+							obj: []invalidTestStruct{
+								{
+									obj: []invalidTestStruct{},
+								},
+							},
+						},
+					}},
+			},
+			want: PageResult[validTestStruct]{
+				oDataNextLink:  nil,
+				oDataDeltaLink: nil,
+			},
+			wantErr: true,
+		},
+		{
+			name: "should return error 'response does not have next link accessor' for missing 'GetOdataNextLink() *string' method",
+			args: args{
+				response: &invalidTestStruct{
+					obj: []invalidTestStruct{
+						{
+							obj: []invalidTestStruct{
+								{
+									obj: []invalidTestStruct{},
+								},
+							},
+						},
+					}},
+			},
+			want: PageResult[validTestStruct]{
+				oDataNextLink:  nil,
+				oDataDeltaLink: nil,
+			},
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := convertToPage[validTestStruct](tt.args.response)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("convertToPage() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			assert.Equal(t, tt.want.oDataDeltaLink, got.oDataDeltaLink, "got %v, want %v", got.oDataNextLink, tt.want.oDataNextLink)
+			assert.Equal(t, tt.want.oDataNextLink, got.oDataNextLink, "got %v, want %v", got.oDataDeltaLink, tt.want.oDataDeltaLink)
+			assert.Equal(t, tt.want.value, got.value, "got %v, want %v", got.value, tt.want.value)
+		})
+	}
+}
+
+type validTestStruct struct {
+	obj []validTestStruct
+}
+
+func (t *validTestStruct) GetValue() []validTestStruct {
+	return t.obj
+}
+
+func (t *validTestStruct) GetOdataNextLink() *string {
+	return nil
+}
+
+func (t *validTestStruct) GetOdataDeltaLink() *string {
+	return nil
+}
+
+type invalidTestStruct struct {
+	obj []invalidTestStruct
+}
+
+func (t *invalidTestStruct) GetOdataDeltaLink() *string {
+	return nil
+}