update tests to match expected value

when multiple labels selected, only issues with all the selected labels will be shown

Author: erjiaqing

models/fixtures/issue_label.yml

@@ -12,3 +12,8 @@
   id: 3
   issue_id: 2
   label_id: 1
+
+-
+  id: 4
+  issue_id: 1
+  label_id: 2

models/issue_test.go

@@ -191,13 +191,21 @@ func TestIssues(t *testing.T) {
 			},
 			[]int64{1, 2, 3, 5},
 		},
+		{
+			IssuesOptions{
+				Labels:   "1",
+				Page:     1,
+				PageSize: 4,
+			},
+			[]int64{2, 1},
+		},
 		{
 			IssuesOptions{
 				Labels:   "1,2",
 				Page:     1,
 				PageSize: 4,
 			},
-			[]int64{5, 2, 1},
+			[]int64{1},
 		},
 	} {
 		issues, err := Issues(&test.Opts)