title: how to config and run objective C test cases in Xcode--XCTest
body: <p>I was reading the document of XCTest(and personally i think the documentation for this part is not that enough) and I thought I should give it a try for a new project(a MAC command-line project, not and iOS project). and then I faced complaints about linking issues--the test case building failed because the conresponsding class .o(if I am not wrong) files are not found. (the error mes here was not recorded by me, sorry)</p>
  
  <p>Then I wanted to delete the test project and in the end I did not even manage to remove the test project. So seriously, how to remove an exsiting project from the solution if the notion in VS applies here?</p>
  
  <p>After failing at that, I removed the auto-generated test file and created my own test case file and strangely, although Xcode detects the existence of the new test case and test method, the build failed and it failed with no issues--no linking issue, no syntax or whatever issue but it just failed. Now I do not know how to move on now as I do not even get a complaint or an error.</p>