automatic extraction of abstract-object-state machines from unit-test executions
An automatic test-generation tool can produce a large number of test inputs to exercise the class under test. However, without specifications, developers cannot inspect the execution of each automatically generated test input practically. To address the problem, we have developed an automatic test abstraction tool, called Abstra, to extract high level object-state-transition information from unit-test executions, without requiring a priori specifications. Given a class and a set of its generated test inputs, our tool extracts object state machines (OSM): a state in an OSM represents an object state of the class and a transition in an OSM represents method calls of the class. When an object state in an OSM is concrete (being represented by the values of all fields reachable from the object), the size of the OSM could be too large to be useful for inspection. To address this issue, we have developed techniques in the tool to abstract object states based on returns of observer methods, branch coverage of methods, and individual object fields, respectively. The tool provides useful object-state-transition information for programmers to inspect unit-test executions effectively. In particular, the tool helps facilitate correctness inspection, program understanding, fault isolation, and test characterization.
extraction abstraction object test automatic test tool input exercise class developer inspection addressing transit informal state machine method values size observability coverage programmer correctness program understanding understandability fault isolates characterization unit test software testing debugging automatic test generation