def test_varchar_raise(self):
        for type_ in (
            String,
            VARCHAR,
            String(),
            VARCHAR(),
            NVARCHAR(),
            Unicode,
            Unicode(),
        ):
            type_ = sqltypes.to_instance(type_)
            assert_raises_message(
                exc.CompileError,
                "VARCHAR requires a length on dialect mysql",
                type_.compile,
                dialect=mysql.dialect()
            )

            t1 = Table('sometable', MetaData(),
                Column('somecolumn', type_)
            )
            assert_raises_message(
                exc.CompileError,
                r"\(in table 'sometable', column 'somecolumn'\)\: "
                r"(?:N)?VARCHAR requires a length on dialect mysql",
                schema.CreateTable(t1).compile,
                dialect=mysql.dialect()
            )

 def test_cast_grouped_expression_pre_4(self):
     dialect = mysql.dialect()
     dialect.server_version_info = (3, 2, 3)
     self.assert_compile(
         cast(sql.column('x') + sql.column('y'), Integer),
         "(x + y)",
         dialect=dialect
     )

 def test_cast_grouped_expression_pre_4(self):
     dialect = mysql.dialect()
     dialect.server_version_info = (3, 2, 3)
     with expect_warnings("Current MySQL version does not support CAST;"):
         self.assert_compile(
             cast(sql.column('x') + sql.column('y'), Integer),
             "(x + y)",
             dialect=dialect
         )

 def test_no_cast_pre_4(self):
     self.assert_compile(
         cast(Column("foo", Integer), String), "CAST(foo AS CHAR)"
     )
     dialect = mysql.dialect()
     dialect.server_version_info = (3, 2, 3)
     with expect_warnings("Current MySQL version does not support CAST;"):
         self.assert_compile(
             cast(Column("foo", Integer), String), "foo", dialect=dialect
         )

 def test_no_cast_pre_4(self):
     self.assert_compile(
                 cast(Column('foo', Integer), String),
                 "CAST(foo AS CHAR)",
         )
     dialect = mysql.dialect()
     dialect.server_version_info = (3, 2, 3)
     self.assert_compile(
                 cast(Column('foo', Integer), String),
                 "foo",
                 dialect=dialect
         )

    def test_match_kw_raises(self):
        m = MetaData()
        Table("t1", m, Column("id", Integer, primary_key=True))
        t2 = Table("t2", m, Column("id", Integer, ForeignKey("t1.id", match="XYZ"), primary_key=True))

        assert_raises_message(
            exc.CompileError,
            "MySQL ignores the 'MATCH' keyword while at the same time causes "
            "ON UPDATE/ON DELETE clauses to be ignored.",
            schema.CreateTable(t2).compile,
            dialect=mysql.dialect(),
        )

    def test_backslash_escaping(self):
        self.assert_compile(
            sql.column('foo').like('bar', escape='\\'),
            "foo LIKE %s ESCAPE '\\\\'"
        )

        dialect = mysql.dialect()
        dialect._backslash_escapes=False
        self.assert_compile(
            sql.column('foo').like('bar', escape='\\'),
            "foo LIKE %s ESCAPE '\\'",
            dialect=dialect
        )

    def test_backslash_escaping(self):
        self.assert_compile(
            sql.column("foo").like("bar", escape="\\"),
            "foo LIKE %s ESCAPE '\\\\'",
        )

        dialect = mysql.dialect()
        dialect._backslash_escapes = False
        self.assert_compile(
            sql.column("foo").like("bar", escape="\\"),
            "foo LIKE %s ESCAPE '\\'",
            dialect=dialect,
        )

 def test_drop_constraint_mysql(self):
     m = MetaData()
     table_name = "testtbl"
     constraint_name = "constraint"
     constraint = CheckConstraint("data IS NOT NULL", name=constraint_name)
     tbl = Table(table_name, m, Column("data", String(255)), constraint)
     dialect = mysql.dialect()
     self.assert_compile(
         schema.DropConstraint(constraint),
         "ALTER TABLE %s DROP CHECK `%s`"
         % (table_name, constraint_name),
         dialect=dialect
     )

 def test_drop_constraint_mariadb(self):
     m = MetaData()
     table_name = "testtbl"
     constraint_name = "constraint"
     constraint = CheckConstraint("data IS NOT NULL", name=constraint_name)
     tbl = Table(table_name, m, Column("data", String(255)), constraint)
     dialect = mysql.dialect()
     dialect.server_version_info = (10, 1, 1, "MariaDB")
     self.assert_compile(
         schema.DropConstraint(constraint),
         "ALTER TABLE %s DROP CONSTRAINT `%s`"
         % (table_name, constraint_name),
         dialect=dialect
     )

 def setup(self):
     dialect = mysql.dialect()
     self.parser = mysql.MySQLTableDefinitionParser(dialect, dialect.identifier_preparer)