*: refine comment

Signed-off-by: Rustin-Liu <rustin.liu@gmail.com>

Author: 0xPoe

ddl/sequence_test.go

@@ -153,7 +153,7 @@ func (s *testSequenceSuite) TestDropSequence(c *C) {
 	c.Assert(err, NotNil)
 	c.Assert(err.Error(), Equals, "[planner:1142]DROP command denied to user 'localhost'@'myuser' for table 'my_seq'")
 
-	// test for if exists.
+	// Test for `drop sequence if exists`.
 	s.tk.MustExec("drop sequence if exists seq_if_exists")
 	s.tk.MustQuery("show warnings;").Check(testkit.Rows("Note 4139 Unknown SEQUENCE: 'test.seq_if_exists'"))
 }

executor/ddl_test.go

@@ -174,7 +174,7 @@ func (s *testSuite6) TestCreateTable(c *C) {
 	r = tk.MustQuery("select * from create_auto_increment_test;")
 	r.Check(testkit.Rows("1000 aa"))
 
-	// test for drop if exists.
+	// Test for `drop table if exists`.
 	tk.MustExec("drop table if exists t_if_exists;")
 	tk.MustQuery("show warnings;").Check(testkit.Rows("Note 1051 Unknown table 'test.t_if_exists'"))
 	tk.MustExec("create table if not exists t1_if_exists(c int)")
@@ -261,7 +261,7 @@ func (s *testSuite6) TestCreateView(c *C) {
 	tk.MustExec("create view v as (select * from t1 union select * from t2)")
 	tk.MustExec("drop view v")
 
-	// test for drop if exists.
+	// Test for `drop view if exists`.
 	tk.MustExec("drop view if exists v_if_exists;")
 	tk.MustQuery("show warnings;").Check(testkit.Rows("Note 1051 Unknown table 'test.v_if_exists'"))
 	tk.MustExec("create view v1_if_exists as (select * from t1)")