Merge pull request #129 from AArnott/stableTesting

Allow more collisions in random testing input generation

src/Xunit.Combinatorial/CombinatorialRandomDataAttribute.cs

@@ -85,7 +85,7 @@ private object[] GenerateValues()
                 collisionCount++;
             }
 
-            if (collisionCount > collisionChecker.Count * 5)
+            if (collisionCount > collisionChecker.Count * 5 && collisionCount > 1000)
             {
                 // We have collided in random values far more than we have successfully generated values.
                 // Rather than spin in this loop, throw.