fix generalize types tests

Author: angelamayxie

sql/types/conversion_test.go

@@ -198,15 +198,16 @@ func TestGeneralizeTypes(t *testing.T) {
 		{Int8, Int8, Int8},
 		{Boolean, Int64, Int64},
 		{Boolean, Boolean, Boolean},
-		{Text, Text, LongText},
+		{Text, Text, Text},
+		{Text, LongText, LongText},
 		{Text, Float64, LongText},
 		{Int64, Text, LongText},
 		{Int8, Null, Int8},
 		{Time, Time, Time},
 		{Time, Date, DatetimeMaxPrecision},
 		{Date, Date, Date},
 		{Date, Timestamp, DatetimeMaxPrecision},
-		{Timestamp, Timestamp, TimestampMaxPrecision},
+		{Timestamp, Timestamp, Timestamp},
 		{Timestamp, Datetime, DatetimeMaxPrecision},
 		{Null, Int64, Int64},
 		{Null, Null, Null},