fix(test): fix malformed test

The child was not being assigned a new parent, causing GetComponentsInChildrenOnly to return empty array and the subsequent line:

Assert.That(components, Has.Length.EqualTo(1));

was resulting in a test fail.

X10D.Unity.Tests/Assets/Tests/ComponentTests.cs

@@ -17,6 +17,7 @@ namespace X10D.Unity.Tests
             var rigidbody = parent.AddComponent<Rigidbody>();
 
             var child = new GameObject();
+            child.transform.SetParent(parent.transform);
             child.AddComponent<Rigidbody>();
 
             Rigidbody[] components = rigidbody.GetComponentsInChildrenOnly<Rigidbody>();