Developers use unit testing to improve the quality of software systems. Current development tools for unit testing help with automating test execution, with reporting results, and with generating test stubs. However, they offer no aid for designing tests aimed specifically at exercising the effects of changes to a program. This demo presents a unit testing tool that leverages a change model to assist developers in the creation of new unit tests. The tool provides developers with quantitative feedback and detailed information about change effects, which not only facilitate the writing of more effective tests, but also motivate developers with an achievable coverage goal.

1. JUNITMX
A Change-aware Unit Testing Tool
Jan Wloka
PROLANGS
Rutgers University
Barbara G. Ryder Frank Tip
Virginia Tech IBM Research
© Jan Wloka 2009 All Rights reserved.

2. Change-aware Tools
Concept: Compare different versions of a program
Decompose edit into 19 distinct atomic changes
Reflecting language semantics
Potential change in dispatch behavior
Inter-dependences between changes
Syntactic, structural requirements
Cause – effect mapping
© Jan Wloka 2009 All Rights reserved.

3. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original
P
I C
M M
AST :: edited
P
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

4. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original
P
I C
C
M M
M M
AST :: edited
P
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

5. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original
P
I C
AC
C
M M
AM AM
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

6. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
P
LC
I C
AC
C
M M
LC
AM AM
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

7. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
call graph :: test1
P
LC
I C
AC
C
M M
LC
AM AM call graph :: test2
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

8. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
call graph :: test1
P
LC
I C
AC
C
M M
LC
AM AM call graph :: test2
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

9. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
call graph :: test1
P
LC
I C
AC
C
M M
LC
AM AM call graph :: test2
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

10. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
call graph :: test1
P
LC
I C
AC
C
M M
LC
AM AM call graph :: test2
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

11. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
call graph :: test1
P
LC
I C
AC
C
M M
LC
AM AM call graph :: test2
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

12. Computing Change Coverage
Program Source Code Atomic Change Model Program Behavior
AST :: original LC
call graph :: test1
P
LC
I C
AC
C
M M
LC
AM AM call graph :: test2
M M
AST :: edited
P CM CM
I C C
M M M M
© Jan Wloka 2009 All Rights reserved.

13. The Tool JUNITMX
CHIANTI :: JDT Plug-in
Setup versions for
comparison
Build change model
JUNITMX :: JUnit Extension
Capture tested program
behavior
Compute change
coverage for each test
© Jan Wloka 2009 All Rights reserved. 4

14. DEMO: Change-centric Testing
The test-first Way!
Goal: Extend Counter to a Multi-Counter application
Add new tests for increment a MultiCounter
Define the feature MultiCounter increment
Explore untested change effects and write new tests
© Jan Wloka 2009 All Rights reserved. 5

15. DEMO: Change-centric Testing
The test-first Way!
Goal: Extend Counter to a Multi-Counter application
Add new tests for increment a MultiCounter
Define the feature MultiCounter increment
Explore untested change effects and write new tests
Support by JUNITMX:
Yellow bar may indicate weak design
Untested Changes assist in design specifications
© Jan Wloka 2009 All Rights reserved. 5

16. DEMO: Change-centric Testing
In test-last manner!
Goal: Add a decrement feature
Add an implementation for decrementing counters
Explore untested changes
Add a new tests exercising the added features
© Jan Wloka 2009 All Rights reserved. 6

17. DEMO: Change-centric Testing
In test-last manner!
Goal: Add a decrement feature
Add an implementation for decrementing counters
Explore untested changes
Add a new tests exercising the added features
Support by JUNITMX:
Yellow bar indicate untested change effects
Changes count motivates test development
Untested Changes assist in writing effective tests
© Jan Wloka 2009 All Rights reserved. 6

18. JUNITMX Infrastructure Overview
JUNITMX
Atomic
Original CHIANTI Changes
Program
Test Run
Call Change
DILA Graphs
Post-
Classification
processing
Edited
Program Test
w/ JUNIT Outcomes
TestSuite
© Jan Wloka 2009 All Rights reserved. 7

19. Under the Hood
Eclipse Workbench Launch Configuration Instrumenting
JVM ClassLoader JVM ClassLoader ClassLoader
Change org.junit.*
IAnalysis
Impact
Processor
Analysis IData runTests()
Collector org.eclipse.jdt.
junit.*
[1]:createChanges() processData(IExecutionData[]) org.eclipse.jdt.
IExecutionData[] internal.junit.*
[3] junitmx.
Instrumenting
Test eclipse.jdt.junit.*
JUnitLaunch
[2] : launch() Runner
Configuration
Wrapper
JUnitMX
Delegate Target
Launch Application
Compute
JUnitMX Add JUnitMX to
Add JUnitMX to
classpath classpath and
classpath
classloader targets
© Jan Wloka 2009 All Rights reserved. 8

20. Research Track:!Friday, 4 -5:30
Grand Ballroom Salon B
Wrapping up “Safe-Commit Analysis to Facilitate
Team Software Development”
JUNITMX provides test coverage of change effects
Test-first: Guide for better design specifications
Test-last: Guide for development of effective tests
Note: Absence of missing changes is not shown!
Other Change-aware tools
Fault finding, Version Control, Refactoring
Follow-ups:
Project: [www.prolangs.rutgers.edu/projects/chianti/]
Updates: [www.wlokas.de/jan/]
© Jan Wloka 2009 All Rights reserved. 9