1. OMEN: A Strategy for Testing Object-Oriented Software
Amie L. Souter
&
Lori L. Pollock
ISSTA 2000
Dept. of Computer and Information Sciences

2. Object-Oriented Programming
Features
Classes, Objects, and Inheritance
Polymorphism and Dynamic Binding
Programming Style
Modularity: many small methods
Objects
Code reuse through inheritance
Complex class interactions
Heavy use of libraries

3. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
intra-method
traditional du analysis Weyuker:85

4. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
intra-method
traditional du analysis Weyuker:85

5. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
inter-method
interprocedural du analysis Harrold:89

6. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
inter-method
interprocedural du analysis Harrold:89

7. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
inter-method
interprocedural du analysis Harrold:89

8. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
intra-class
Intra-class du analysis Harrold & Rothermel: 94

9. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
intra-class
Intra-class du analysis Harrold & Rothermel: 94

10. Illustrating Kinds of DEF-USE Pairs
Class Stack{
int myStack[];
int top;
1 public Stack(int s){ myStack = new int[s];
top = 0; }
3 public void push(int obj){ myStack[top++] = obj; }
4 public int pop(){
if(size() == 0) return error;
int temp = myStack[top-1];
top--;
return temp; }
9 public int size() { return top; }
10 public int top() { return myStack[top-1]; }
11 public boolean isEmpty() { return top == 0; }
12 public void example() { push(10);
if(size() == 5)
do_something++; }
intra-class
Intra-class du analysis Harrold & Rothermel: 94

11. DEF-USE Pairs Involving Inter-Class Interactions
Class genericStack{
Array myStack;
1 public genericStack() { myStack = new Array(); }
2 public Object top() { return myStack.back(); }
3 public void push(Obj o){ myStack.pushBack(o); }
4 public Object pop() { return myStack.popBack(); }
5 public bool isEmpty() { return myStack.isEmpty(); }
6 public int size() { return myStack.size(); } }
Class Array {
Object myStorage[];
int myLength;
1 public Array() { myStorage = new Object[SIZE];
myLength = 0; }
3 public Object back() { return myStorage[myLength-1];}
4 public Object popBack() { return myStorage[--myLength];}
5 public void pushBack(Obj o){ add(o); }
6 public Object front(Obj o) { return myStorage[0]; }
7 public bool isEmpty() { return (myLength == 0) }
8 public int size() { return myLength; }
9 public void add(Obj o){ myStorage[myLength++] = o; }
//Array has 46 other methods }
Inter-class du analysis Souter & Pollock:99

12. DEF-USE Pairs Involving Inter-Class Interactions
Class genericStack{
Array myStack;
1 public genericStack() { myStack = new Array(); }
2 public Object top() { return myStack.back(); }
3 public void push(Obj o){ myStack.pushBack(o); }
4 public Object pop() { return myStack.popBack(); }
5 public bool isEmpty() { return myStack.isEmpty(); }
6 public int size() { return myStack.size(); } }
Class Array {
Object myStorage[];
int myLength;
1 public Array() { myStorage = new Object[SIZE];
myLength = 0; }
3 public Object back() { return myStorage[myLength-1];}
4 public Object popBack() { return myStorage[--myLength];}
5 public void pushBack(Obj o){ add(o); }
6 public Object front(Obj o) { return myStorage[0]; }
7 public bool isEmpty() { return (myLength == 0) }
8 public int size() { return myLength; }
9 public void add(Obj o){ myStorage[myLength++] = o; }
//Array has 46 other methods }
Inter-class du analysis Souter & Pollock:99

13. DEF-USE Pairs Involving Inter-Class Interactions
Class genericStack{
Array myStack;
1 public genericStack() { myStack = new Array(); }
2 public Object top() { return myStack.back(); }
3 public void push(Obj o){ myStack.pushBack(o); }
4 public Object pop() { return myStack.popBack(); }
5 public bool isEmpty() { return myStack.isEmpty(); }
6 public int size() { return myStack.size(); } }
Class Array {
Object myStorage[];
int myLength;
1 public Array() { myStorage = new Object[SIZE];
myLength = 0; }
3 public Object back() { return myStorage[myLength-1];}
4 public Object popBack() { return myStorage[--myLength];}
5 public void pushBack(Obj o){ add(o); }
6 public Object front(Obj o) { return myStorage[0]; }
7 public bool isEmpty() { return (myLength == 0) }
8 public int size() { return myLength; }
9 public void add(Obj o){ myStorage[myLength++] = o; }
//Array has 46 other methods }
Inter-class du analysis Souter & Pollock:99

14. DEF-USE Pairs Involving Inter-Class Interactions
Class genericStack{
Array myStack;
1 public genericStack() { myStack = new Array(); }
2 public Object top() { return myStack.back(); }
3 public void push(Obj o){ myStack.pushBack(o); }
4 public Object pop() { return myStack.popBack(); }
5 public bool isEmpty() { return myStack.isEmpty(); }
6 public int size() { return myStack.size(); } }
Class Array {
Object myStorage[];
int myLength;
1 public Array() { myStorage = new Object[SIZE];
myLength = 0; }
3 public Object back() { return myStorage[myLength-1];}
4 public Object popBack() { return myStorage[--myLength];}
5 public void pushBack(Obj o){ add(o); }
6 public Object front(Obj o) { return myStorage[0]; }
7 public bool isEmpty() { return (myLength == 0) }
8 public int size() { return myLength; }
9 public void add(Obj o){ myStorage[myLength++] = o; }
//Array has 46 other methods }
Inter-class du analysis Souter & Pollock:99

15. DEF-USE Pairs Involving Inter-Class Interactions
Class genericStack{
Array myStack;
1 public genericStack() { myStack = new Array(); }
2 public Object top() { return myStack.back(); }
3 public void push(Obj o){ myStack.pushBack(o); }
4 public Object pop() { return myStack.popBack(); }
5 public bool isEmpty() { return myStack.isEmpty(); }
6 public int size() { return myStack.size(); } }
Class Array {
Object myStorage[];
int myLength;
1 public Array() { myStorage = new Object[SIZE];
myLength = 0; }
3 public Object back() { return myStorage[myLength-1];}
4 public Object popBack() { return myStorage[--myLength];}
5 public void pushBack(Obj o){ add(o); }
6 public Object front(Obj o) { return myStorage[0]; }
7 public bool isEmpty() { return (myLength == 0) }
8 public int size() { return myLength; }
9 public void add(Obj o){ myStorage[myLength++] = o; }
//Array has 46 other methods }
Inter-class du analysis Souter & Pollock:99

16. Research Goals
To develop a new approach to testing object-oriented software that:
Provides structural testing tailored to OO codes
association between objects and fields
include object creation site with def-use pair
handle complex class interactions
Program representation scales to large software systems
Provides feedback to the tester
Provides information on external influences of the testing results
Provides the tester with direction in how to test an incomplete program

17. Outline Object-Oriented Program Characteristics
Illustration of Def-Use Pairs
Research Goals
Our Solution
Basic Object Manipulations
Annotated Points-to Escape Graph
OMEN: Test Tuple Construction Algorithm
Work in Progress

18. Basic Object Manipulations

19. Basic Object Manipulations

20. Basic Object Manipulations

21. Points-to-Escape-Graph
Terminology
Nodes
inside
outside
load
return value
Edges
Node insert(Object e) {
Node temp = new Node (e,this);
return temp; } e
data
next
this
temp
Whaley & Rinard: OOPSLA99

22. Extensions to the Points-to-Escape Graph:APE Graph
1: public push( Object e){
2: if(top == null)
3: top = new Node(e, null);
4: else
5: top = top.insert(e); }
6: Node (Object e, Node n ){
7: data = e;
8: next = n;
this e

23. Extensions to the Points-to-Escape Graph:APE Graph
1: public push( Object e){
2: if(top == null)
3: top = new Node(e, null);
4: else
5: top = top.insert(e); }
6: Node (Object e, Node n ){
7: data = e;
8: next = n;
this e
top,2,load

24. Extensions to the Points-to-Escape Graph:APE Graph
1: public push( Object e){
2: if(top == null)
3: top = new Node(e, null);
4: else
5: top = top.insert(e); }
6: Node (Object e, Node n ){
7: data = e;
8: next = n;
this e
data,3-7,store 3
next,3-8,store T
top,3,store
top,2,load

25. OMEN - Test Tuple Construction Algorithm
Computes a set of testing tuples for the component under test,
based on object manipulations.
Input: set of call graphs for component under test
Output: set of testing tuples for component under test
Traverse call graph in topological order
Process each method’s APE graph
For each store annotation per unmarked APE graph edge
find the associated loads occurring after the store
find object creation site associated with the tuple
depends on the type of source node of the APE graph
report feedback
using the escape information of the APE graph

26. Traverse the Call Graph in Topological Order
main
push
pop
Stack
isempty
println
get
remove
Node
insert

27. Traverse the Call Graph in Topological Order
main: 1
push: 3
pop:7
Stack:2
isempty:6
println:10
get:8
remove:9
Node:4
insert:5

28. Processing a Method’s APE Graph
x,22
Integer 20 20
data:9
data:8
next:7
next:5
20-4
top:2
next:6
next:4
s,18 18
top:1
top:3

29. Processing a Method’s APE Graph
x,22
Integer 20 20
data:9
data:8
next:7
next:5
20-4
top:2
next:6
next:4
s,18 18
top:1
top:3

30. Processing a Method’s APE Graph
x,22
Integer 20 20
data:9
data:8
next:7
next:5
20-4
top:2
next:6
next:4
s,18 18
top:1
top:3

31. Avoiding Duplicate Tuples Through Marking
this e 1
data, , store
data,3-7,store 4 3 T
top,3,store
next,3-8,store
next,4-10-8,store
top,2,load 2
Marked edge
Non-marked edge
top,4,store
Edges are marked during interprocedural merges of ape graph construction.

32. Processing Incomplete Components
x,22
top:1
s,18 18
top:2
top:4
top:3
Feedback: value loaded is potentially
changed by method outside CUT.

33. Processing Incomplete Components
x,22
top:1
s,18
top:2
top:4
top:3
Feedback: value loaded is potentially
changed by method outside CUT.

34. Processing Incomplete Components
x,22
top:1
s,18
top:2
top:4
top:3
Feedback: value loaded is potentially
changed by method outside CUT.

35. Work in Progress APE Graph Test Tuple Construction Algorithm
Implementation of the APE graph
Empirical study of the space and time requirements
Empirical characterization study of the object manipulations in real object-oriented codes
Test Tuple Construction Algorithm
Algorithm extensions to include coverage for object manipulations based on references only
Algorithm modifications - more sophisticated techniques to eliminate infeasible paths
Evaluation of the algorithm