Tao Xie ( taoxie@cs.washington.edu ) Advisor: David Notkin Department of Computer Science & Engineering, Universit

1. Automatic Identification of Common and Special Object-Oriented Unit Tests Commontests Common oruniversal properties Specialtests Abstractiontemplates Problem Solution Testidentification Method-call composition Test generation Statisticalinference References Related Work Tao Xie (taoxie@cs.washington.edu) Advisor: David Notkin Department of Computer Science & Engineering, University of Washington, Seattle Results for java.util.LinkedList • g(f(S, args1).state, args2).retval == const • g(f(S, args1).state, args2).state == f(g(S, args1).state, args2).state • … S1 • Programmers often overlook some special or even commontests • Automatic test generation tools produce a large number of tests • How to automatically identify special tests and common tests from them? • 79 common tests and 29 special tests (8 tests are both common and special) identified out of 6777 automatically generated tests. • 43 universal properties and 45 common properties. • Generate representative method arguments • Iteratively invoke different arguments on each non-equivalent receiver-object(e.g. five iterations) • [Xie et al. 04] clear … S2 == S3 size … Some Examples of Common/Special Tests S4 *. Common prop: remove(removeLast(S).state, m0_2).state == removeLast(remove(S, m0_2).state).state Satisfying count: 318 (common test) LinkedList m = new LinkedList( ); m.add (0, new Integer(-1)); m.removeLast( ); m.remove(new Integer(-1)); Violating count: 42 (special test) LinkedList m = new LinkedList( ); m.add (0, new Integer(-1)); m.add (0, new Integer(0)); m.removeLast( ); m.remove(new Integer(-1)); *. Common prop: remove(removeFirst(S).state, m0_2).retval == remove(S, m0_2).retval Satisfying count: 315 (common test) LinkedList m = new LinkedList( ); m.add (0, new Integer(-1)); m.removeFirst ( ); m.remove(new Integer(1)); Violating count: 45 (special test) LinkedList m = new LinkedList( ); m.add (0, new Integer(-1)); m.removeFirst ( ); m.remove(new Integer(-1)); Java class bytecode • Automatically identify common and special tests without requiring specifications • Based on dynamically inferred Statistical Algebraic Abstractions class bytecode *. Common prop: removeLast(addFirst(S, m0_1).state).state == addFirst(removeLast(S).state, m0_1).state Satisfying count: 117 (common test) LinkedList m = new LinkedList( ); m.add(0, new Integer(-1)); m.addFirst(new Integer(0)); m.removeLast ( ); Violating count: 3 (special test) LinkedList m = new LinkedList( ); m.addFirst(new Integer(0)); m.removeLast ( ); *. Conditional universal prop: lastIndexOf(addFirst(S, m0_1).state, m0_2).retval == (lastIndexOf(S, m0_2).retval + 1) [where (m0_1==m0_2)] Satisfying count: 120 (special test) LinkedList m = new LinkedList( ); m.addFirst(new Integer(-1)); m.lastIndexOf(new Integer(-1)); • Syntactically identical to axioms in algebraic specifications • Associated with counts of satisfying and violating instances • Universal property: all instances are satisfying instances. • Common property: instances are mostly (e.g. 80%)satisfying instances • Common testa satisfying instance of a universal property or common property • Special testa violating instance of a common property size(clear(S).state).retval == 0 Satisfying count: 121 Violating count: 0 remove(add(S, m0_1).state, m0_2).state == add(remove(S, m0_2).state, m0_1).state Satisfying count: 315 Violating count: 45 • Ernst et al., Dynamically Discovering Likely Program Invariants to Support Program Evolution, IEEE Trans. Softw. Eng, 01. • Henkel & Diwan, Discovering Algebraic Specifications from Java Classes, ECOOP 03. • Xie et al., Rostra: A Framework for Detecting Redundant Object-Oriented Unit Tests, ASE 04. • Statistical algebraic abstractions are not required to be universally true during test executions, different from properties inferred by previous approaches • [Ernst et al. 01, Henkel & Diwan 03]. java.util.LinkedList as the illustrative example 25 pub methods and more than 300 LOC http://www.cs.washington.edu/homes/taoxie/sabicu/