IF EXISTS (SELECT * FROM sys.procedures WHERE Name = 'Test')
DROP PROC Test
CREATE PROCEDURE Test
However, with SQL Server 2016 SP1, now there is easy way of doing with one statement.
CREATE OR ALTER PROCEDURE Test
Obvious advantage is this is much cleaner now. This feature is available for Functions, Triggers and Views as well.
There is an another important benefits out of this.
If you check the stored procedure stats for the drop and create method by running the following query, you will end up with below results.
FROM sys.procedures WHERE Name = 'Test'
In this, both the create and the modify dates are same. However, for the new method, now it has a different modify date which means you can track your objects much better.