title: TDD approach issue with test
body: <p>I'm new to TDD practice and i was wondering if my approach is good from a special case.</p>
  
  <p>I want to program a little software that takes a group of array strings in parameter and split all string in that group.</p>
  
  <p>Example : </p>
  
  <p>{"C - 3 - 3", "M - 5 - 5"} should return { {"C", "3", "3"}, {"M", "5", "5"} }</p>
  
  <p>By cutting out the problem, i started with a StringSplitter and StringSplitterTest with TDD in order to split just one string to an array of string.</p>
  
  <p>After, i programmed a StringGroupSplitter and StringGroupSplitterTest (always with the TDD approach) doing the same thing but with a array of strings (knowing that StringGroupSplitter has a StringSplitter dependency).</p>
  
  <p>So, i remembered the "FIRST" principles of unit tests and in particular the principle of independence saying that a test should not depend on the result of another test.</p>
  
  <p>In my case, the problem is that due to the dependency of StringGroupSplitter and StringSplitter, if only ont test fails in StringSplitterTest, tests in StringGroupSplitterTest will also fail.</p>
  
  <p>So my question is the following : Is my approach to TDD the right one ?</p>
  
  <p>Thanks in advance.</p>