Shrink a large log file for a "Throw Away" database
You have two options:

1) Run a LOG backup of the database:

BACKUP LOG foo TO DISK='X:\BackupLocation';


2) Set the recovery model to SIMPLE and checkpoint it.

ALTER DATABASE foo SET RECOVERY SIMPLE;
CHECKPOINT;


This is all part of SQL Server's different recovery models.  Based on you working on this in DEV, I'd probably go the second option since it sounds like you don't need to worry about point in time recovery.

Note, this will simply clear out the active transactions, not reduce the actual file size.  Once this is complete, you can then shrink the log file.