title: GoogleTest force #undef on particular test
body: <p>I use GoogleTest, and I want to test some functions with #ifndef inside.</p>
  
  <p>file a.c</p>
  
  <pre><code>bool myFunction() {
  #ifndef FOO
     return true;
  #else   
     return false;
  #endif
  }
  </code></pre>
  
  <p>Is it possible to force an #undef during a particular test ? Like that I can test the function in the 2 stats (with the define and without).</p>