In ICSE’08 we demonstrated the Java UML Lightweight Enumerator (JULE) tool, which supports compliance test generation from modeling standards specifications. When employed in our framework for software tool certification, JULE provides a powerful technology to enumerate a set of test cases that exhaustively test a modeling tool. JULE avoids combinatorial explosion by generating test cases only up to non-isomorphism. In this paper, a case study presented is an experiment on the use of a test suite generated from JULE to assess the compliance of an open source software tool - ArgoUML. This case study illustrates how ArgoUML is tested and reveals some previously unknown non-compliance issues. The case study highlights how software modeling tools can be tested for standards compliance and how test results can be analyzed to diagnose the causes of noncompliance in a software tool.