How-to organize integration tests and unit tests

Is it ok to have integration tests and unit tests in one assembly 开发者_运维知识库(project) ? Or rather have them separate ?

Personally I prefer to put them into separate assemblies. During continuous integration builds it is easier to distinguish between them because tools can be configured to execute all tests in a given assembly and you could for example want to run only unit tests or only integration tests which might take more time.