The source code of a software artifact may be scanned, and a call tree model with leaf nodes may be generated based on the scan. A set of test cases can be executed against the software artifact and log data from the execution can be collected. A set of untested leaf nodes can be detected and a new set of test cases can be generated to test the untested nodes. The new set of test cases are executed and a subset of the test cases which cover the previously untested nodes are added to the existing set of test cases.