Simulate a SQL deadlock (Source: https://stackoverflow.com/questions/11569964/how-to-simulate-a-deadlock-in-sql-server-in-a-single-process)

sp_simulatedeadlock.sql

/*
This script helps simulate deadlocks.  Run the entire script in a SQL query window.  It will continue running until stopped.
In the target script, insert a call to sp_simulatedeadlock where you want the deadlock to occur.
This stored procedure, also created below, causes the deadlock.
When you are done, stop the execution of this window and run the code in the cleanup section at the bottom.
*/
SET NOCOUNT ON

IF OBJECT_ID('DeadlockTest') IS NOT NULL
    DROP TABLE DeadlockTest

CREATE TABLE DeadlockTest
    (
        Deadlock_Key INT PRIMARY KEY CLUSTERED ,
        Deadlock_Count INT
    )
GO

IF EXISTS (   SELECT *
              FROM   sys.sysobjects
              WHERE  id = OBJECT_ID(N'sp_simulatedeadlock')
                     AND OBJECTPROPERTY(id, N'IsProcedure') = 1
          )
    DROP PROCEDURE sp_simulatedeadlock
GO

CREATE PROCEDURE sp_simulatedeadlock
    (
        @MaxDeadlocks INT = -1 -- specify the number of deadlocks you want; -1 = constant deadlocking
    )
AS
    BEGIN

        SET NOCOUNT ON

        IF OBJECT_ID('DeadlockTest') IS NULL
            RETURN

        -- Volunteer to be a deadlock victim.
        SET DEADLOCK_PRIORITY LOW

        DECLARE @DeadlockCount INT

        SELECT @DeadlockCount = Deadlock_Count -- this starts at 0
        FROM   DeadlockTest
        WHERE  Deadlock_Key = 2

        -- Trace the start of each deadlock event.
        -- To listen to the trace event, setup a SQL Server Profiler trace with event class "UserConfigurable:0".
        -- Note that the user running this proc must have ALTER TRACE permission.
        -- Also note that there are only 128 characters allowed in the trace text.
        DECLARE @trace NVARCHAR(128)

        IF @MaxDeadlocks > 0
           AND @DeadlockCount > @MaxDeadlocks
            BEGIN

                SET @trace = N'Deadlock Test @MaxDeadlocks: '
                             + CAST(@MaxDeadlocks AS NVARCHAR)
                             + N' @DeadlockCount: '
                             + CAST(@DeadlockCount AS NVARCHAR)
                             + N' Resetting deadlock count.  Will not cause deadlock.'
                EXEC sys.sp_trace_generateevent @eventid = 82 , -- 82 = UserConfigurable:0 through 91 = UserConfigurable:9
                                                @userinfo = @trace

                -- Reset the number of deadlocks.
                -- Hopefully if there is an outer transaction, it will complete and persist this change.
                UPDATE DeadlockTest
                SET    Deadlock_Count = 0
                WHERE  Deadlock_Key = 2
                RETURN
            END

        SET @trace = N'Deadlock Test @MaxDeadlocks: '
                     + CAST(@MaxDeadlocks AS NVARCHAR) + N' @DeadlockCount: '
                     + CAST(@DeadlockCount AS NVARCHAR)
                     + N' Simulating deadlock.'
        EXEC sys.sp_trace_generateevent @eventid = 82 , -- 82 = UserConfigurable:0 through 91 = UserConfigurable:9
                                        @userinfo = @trace

        DECLARE @StartedTransaction BIT
        SET @StartedTransaction = 0
        IF @@trancount = 0
            BEGIN
                SET @StartedTransaction = 1
                BEGIN TRANSACTION
            END

        -- lock 2nd record
        UPDATE DeadlockTest
        SET    Deadlock_Count = Deadlock_Count
        FROM   DeadlockTest
        WHERE  Deadlock_Key = 2

        -- lock 1st record to cause deadlock
        UPDATE DeadlockTest
        SET    Deadlock_Count = Deadlock_Count
        FROM   DeadlockTest
        WHERE  Deadlock_Key = 1

        IF @StartedTransaction = 1
            ROLLBACK
    END
GO

INSERT INTO DeadlockTest (   Deadlock_Key ,
                             Deadlock_Count
                         )
            SELECT 1 ,
                   0
            UNION
            SELECT 2 ,
                   0

-- Force other processes to be the deadlock victim.
SET DEADLOCK_PRIORITY HIGH

BEGIN TRANSACTION

WHILE 1 = 1
    BEGIN

        BEGIN TRY

            BEGIN TRANSACTION

            -- lock 1st record
            UPDATE DeadlockTest
            SET    Deadlock_Count = Deadlock_Count
            FROM   DeadlockTest
            WHERE  Deadlock_Key = 1

            WAITFOR DELAY '00:00:10'

            -- lock 2nd record (which will be locked when the target proc calls sp_simulatedeadlock)
            UPDATE DeadlockTest
            SET    Deadlock_Count = Deadlock_Count
            FROM   DeadlockTest
            WHERE  Deadlock_Key = 2

            ROLLBACK

        END TRY
        BEGIN CATCH
            PRINT 'Error ' + CONVERT(VARCHAR(20), ERROR_NUMBER()) + ': '
                  + ERROR_MESSAGE()
            GOTO cleanup
        END CATCH

    END

cleanup:

IF @@trancount > 0
    ROLLBACK

DROP PROCEDURE sp_simulatedeadlock
DROP TABLE DeadlockTest