Add tests for normalize method (go-mysql-org#226)

Author: lnx

mysql/mysql_gtid.go

@@ -97,7 +97,11 @@ func (s IntervalSlice) Normalize() IntervalSlice {
 n = append(n, s[i])
 continue
 } else {
-n[len(n)-1] = Interval{last.Start, s[i].Stop}
+stop := s[i].Stop
+if last.Stop > stop {
+stop = last.Stop
+}
+n[len(n)-1] = Interval{last.Start, stop}
 }
 }
 

mysql/mysql_test.go

@@ -60,6 +60,12 @@ func (t *mysqlTestSuite) TestMysqlGTIDIntervalSlice(c *check.C) {
 n = i.Normalize()
 c.Assert(n, check.DeepEquals, IntervalSlice{Interval{1, 3}, Interval{4, 5}})
 
+i = IntervalSlice{Interval{1, 4}, Interval{2, 3}}
+i.Sort()
+c.Assert(i, check.DeepEquals, IntervalSlice{Interval{1, 4}, Interval{2, 3}})
+n = i.Normalize()
+c.Assert(n, check.DeepEquals, IntervalSlice{Interval{1, 4}})
+
 n1 := IntervalSlice{Interval{1, 3}, Interval{4, 5}}
 n2 := IntervalSlice{Interval{1, 2}}