You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: enum_test.go
    path of file: ./repos/cockroach/pkg/sql/tests
    
    the code of the file until where you have to start completion: // Copyright 2021 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/
    
func TestEnumDropValueCheckConstraint(t *testing.T) {
	defer leaktest.AfterTest(t)()
	defer log.Scope(t).Close(t)

	ctx := context.Background()
	s, conn, _ := serverutils.StartServer(t, base.TestServerArgs{})
	defer s.Stopper().Stop(ctx)

	db := sqlutils.MakeSQLRunner(conn)
	db.Exec(t, "CREATE TYPE typ AS ENUM ('a', 'b', 'c')")

	// Check that an enum value cannot be dropped if it is referenced in a table's
	// check constraint.
	db.Exec(t, "CREATE TABLE t1 (k typ CHECK (k::typ = 'a'))")
	db.ExpectErr(t, "^pq: could not remove enum value \"a\" as it is being used in a check constraint of \"t1\"$",
		"ALTER TYPE typ DROP VALUE 'a'")

	db.Exec(t, "DROP TABLE t1")
	db.Exec(t, "ALTER TYPE typ DROP VALUE 'a'")

	// Check that the enum value cannot be dropped even if it is referenced only
	// in a table's check constraint.
	db.Exec(t, "CREATE TABLE t2 (k STRING CHECK (k::typ = 'b'))")
	db.ExpectErr(t, "^pq: could not remove enum value \"b\" as it is being used in a check constraint of \"t2\"$",
		"ALTER TYPE typ DROP VALUE 'b'")

	db.Exec(t, "DROP TABLE t2")
	db.Exec(t, "ALTER TYPE typ DROP VALUE 'b'")
}