Add an Assertion to a Test Step using Java API

I want to be able to add an assertion to a test step using the Java API.

We work with a multiserver environment whereby we deploy services to multiple production servers during a deployment cycle. We want to be able to certify one of the servers in the cluster by eyeballing the results and then run a regression suite against that one server. The results of the test suite ran against that one server should become the assertsion of the test suite. Using those assertions we can certify the rest of the servers in the cluster during the deployment cycle.

We would much prefer to add the assertions to the test steps using Java as opposed to groovy - a Java implementation would fit better with our overall architecture.

However, if Groovy is the only solution we'll work around it.

Hopefully you understand what I am trying to achieve.

In short, does anyone have a code snippet in Java that takes the results of a test Step and adds those results to the test Step as an assertion?

Any help sure appreciated!
Conor