problem in nunit testcases

i m writing unit testcases for a class,

I want to create a db file in setup mak开发者_如何学Ce the testcase to use it and delete the file in teardown

the problem is the time taken to copy is not predicted and sometimes the teardown cannot able to delete the file

help me please..

code in setup has File.Copy to copy the file

in teardown it has File.Delete to delete the file

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What sort of DB are you creating? Can it not be created in memory?