VS2008 Unit Tests: Order of Execution

Question

Folks,

My apologies for the novice question. It's probably obvious, please don't laugh :-)

I have unit tests defined for my Visual Studio 2008 solution. These tests are defined in multiple methods, in multiple classes across several files.

I've read in a blog article that depending on the order of execution of tests is wrong; that said, I have to have a pre-execution step before any of these tests gets to run. I.e. I actually want to define an order of execution somehow - i.e. first I create the database; then I test that it's created; then the remaining 50 tests can run in arbitrary order.

Any ideas on how I can do that?

Answer 1

I wouldn't test that the database is successfully created; I will assume that all subsequent tests will fail if it is not, and it feels in a way that you would be testing the test code.

Regarding a pre-test step to set up the database, you can do that by creating a method and decorating it with the ClassInitialize attribute. That will make the test framework execute that method prior to any other method within the test class:

[ClassInitialize()]
public static void InitializeClass(TestContext testContext) 
{ 
    // your init code here
}

Answer 2

Unit tests should all work standalone, and should not have dependencies on each other, otherwise you can't run a single test in isolation.

Every test that needs the database should then just create it on demand (if it's not already been created - you can use a singleton/static class to ensure that if multiple tests are executed in a batch, the database is only actually created once).

Then it won't matter which test executes first; it'll just be created the first time a test needs a database to use.