public void SetUp()
 {
     _dependencies = new Dependencies();
     _dependencies.AddDirect("A", new[] { "B", "C" });
     _dependencies.AddDirect("B", new[] { "C", "E" });
     _dependencies.AddDirect("C", new[] { "G" });
     _dependencies.AddDirect("D", new[] { "A", "F" });
     _dependencies.AddDirect("E", new[] { "F" });
     _dependencies.AddDirect("F", new[] { "H" });
 }