Install Microsoft SQL Management Studio, which you can download for free from Microsoft’s website:
Version 2008
Microsoft SQL Management Studio 2008 is part of SQL Server 2008 Express with Advanced Services
Version 2012
Click download button and check ENUx64SQLManagementStudio_x64_ENU.exe
Version 2014
Click download button and check MgmtStudio 64BITSQLManagementStudio_x64_ENU.exe
Open Microsoft SQL Management Studio.
Backup original database to .BAK file (db -> Task -> Backup).
Create empty database with new name (clone). Note comments below as this is optional.
Click to clone database and open restore dialog (see image)
Select Device and add the backup file from step 3.
Change destination to test database
Change location of database files, it must be different from the original. You can type directly into text box, just add postfix. (NOTE: Order is important. Select checkbox, then change the filenames.)
Check WITH REPLACE and WITH KEEP_REPLICATION
Right-click the database to clone, click Tasks, click Copy Database…. Follow the wizard and you’re done.