CREATE OR ALTER PROCEDURE [test abc].[test abc1]
AS
BEGIN
    -- Arrange
    EXEC tSQLt.FakeTable 'dbo', 'table1';
    -- Here the NOT NULL constraint should be put back on table1 column col1
    EXEC [tSQLt].[ExpectNoException]
    -- Act + Assert
    INSERT INTO .....
END
GO

UPDATE MYTABLE
SET MyColumn = 'Default Value'
WHERE MyColumn IS NULL

ALTER TABLE MYTABLE
AlTER COLUMN MyColumn DATATYPE NOT NULL