1. CS427: Software Engineering I
Grigore Rosu

2. Today’s goals Quick Logistics Testing 1 Quiz 1 discussion
jUnit – basic notions, demo by Tao Mo
Selenium – very basic notions, demo by Yi Zhang

3. Course Logistics
Wiki: (videos!)
Piazza:
Compass:
All class-wide announcements through compass or my.cs
MP1 due today, 23:59; MP2 due Monday, 23:59
Follow the rules and the format specified on Wiki!
Office hours by request (Piazza)
Qing Ye also offers regular office hours on Tu/Th 3-4pm, SC4105
Used also for makeup quizzes: Mon quiz ~> Tu; Wed quiz ~> Th
Reminder
MPs (30%), final exam (25%), project (40%), quizzes (5%)
Bonus up to 3% for active participation (lectures, Piazza, …)
Lots of “broad but shallow” reading
Read, read, read everything we list on the wiki
Book chapters and papers will be on EXAM

4. Quiz 1 Discussion - General -
Regular office hours?
Yes, we have those too, now
Makeup quizzes?
Yes: take makeup quiz next day at regular office hour
Make announcements clear, both on Piazza and Compass
Will do

5. Quiz 1 Discussion - Lectures -
Speak louder; make sure microphone is working
Will do; you should also tell me during class
Too dry/boring/theoretical sometimes, not interesting / useful, feels like a business class
Will try to add more pictures, more real-life examples and experiences; do more interactive activities; trends in industry, transformative/disruptive products
Some contradictory messages:
More general concepts!
More specific concepts!
Lectures and MPs should be more related
Will discuss the MPs more in class, demos

6. Quiz 1 Discussion - MPs -
Excellent, love them, useful! Clear, easy to understand!
Confusing, not clear what is required; too antique, need to be modernized; feel random, unrelated 
Will do our best to make things clearer
Note that we inherited them
Related to project
Rounds of autograding?
Probably not feasible this semester; will do in the future

7. Testing 1 jUnit Selenium

8. Goals Why test and what are major terminologies in testing?
How to use JUnit to write unit tests?

9. Why test? Improve quality – find faults (or defects, or bugs)
Measure quality
Prove there are no faults? (Is it possible?)
Determine if software is ready to be released
Determine what to work on
See if you made a mistake
Learn the software

10. What is a test?
Run program with known inputs (test inputs/data), check results (with test oracles)
Tests pass (green) or fail (red)
Tests can document faults
Tests can document code
Important terminology to remember:
Mistake, fault (or defect, or bug), failure, error
Oracle

11. Recall Terminology: Mistake, Fault/Bug, Failure, Error
Programmer makes a mistake
Fault (defect, bug) appears in the program
Fault remains undetected during testing
Program failure occurs during execution
(program behaves unexpectedly)
Error: difference between computed, observed, or measured value or condition and true, specified, or theoretically correct value or condition

12. Terminology: Mistake, Fault/Bug, Failure, Error
Running the test inputs …
Programmer makes a mistake
Fault (defect, bug) appears in the program
Fault remains undetected during testing
Program failure occurs during execution
(program behaves unexpectedly)
Error: difference between computed, observed, or measured value or condition and true, specified, or theoretically correct value or condition

13. Terminology: Mistake, Fault/Bug, Failure, Error
Based on
test oracles …
Programmer makes a mistake
Fault (defect, bug) appears in the program
Fault remains undetected during testing
Program failure occurs during execution
(program behaves unexpectedly)
Error: difference between computed, observed, or measured value or condition and true, specified, or theoretically correct value or condition

14. Terminology: Mistake, Fault/Bug, Failure, Error
What does bug mean in “bug report”?
Programmer makes a mistake
Fault (defect, bug) appears in the program
Fault remains undetected during testing
Program failure occurs during execution
(program behaves unexpectedly)
Error: difference between computed, observed, or measured value or condition and true, specified, or theoretically correct value or condition

15. Where is fault, error, or failure?
Objective: double the balance and then add 10
int calAmount () {
int ret = balance * 3;
ret = ret + 10;
return ret; }
Where is test input?
Where is test oracle?
void testCalAmount() { Account account = new Account();
account.setBalance(0);
int amount = account.calAmount();
assertTrue(amount == 10); }

16. Where is fault, error, or failure?
Objective: double the balance and then add 10
int calAmount () {
int ret = balance * 3;
ret = ret + 10;
return ret; }
Where is test input?
Where is test oracle?
Is this a good test?
void testCalAmount() { Account account = new Account();
account.setBalance(0);
int amount = account.calAmount();
assertTrue(amount == 10); }

17. Where is fault, error, or failure?
Objective: double the balance and then add 10
int calAmount () {
int ret = balance * 3;
ret = ret + 10;
return ret; }
Try some input different from 0?
void testCalAmount() { Account account = new Account();
account.setBalance(1);
int amount = account.calAmount();
assertTrue(amount == 12); }

18. Where is fault, error, or failure?
Objective: disallow withdrawal when balance is 100 or less
boolean doWithdraw(int amount) { if (balance < 100) return false; else return withDraw(amount); }
void testWithDraw() { Account account = new Account();
account.setBalance(100);
boolean success = account.doWithdraw(10);
assertTrue(!success); }

19. Who should test? Developer / programmer?
Separate “quality assurance” group?
User?
Someone with a degree in “testing”?

20. What kind of tests? Programmer tests / non-programmer tests
Developer / Tester
Unit tests / Integration tests / Functional tests / System tests
Automated tests / Manual tests
Regression tests
Exploratory testing

21. What kind of tests? Manual Automatic Good for exploratory
Good for testing GUI
Manual regression testing is BORING
Automatic
Test is a program
Test is created by a tool that records user actions

22. Test automation Tests are code or scripts (which is code)
Real projects can often have more test code than production code
Test code is boring
Build some complex data values
Run a function
Check the result

23. xUnit testing tools Programmer’s testing tools Automated testing!
Unit testing, but also integration testing and functional testing
Regression testing
Test-first design
Each code unit requires several tests

24. What is JUnit?
Open source (junit.org) Java testing framework used to write and run repeatable automated tests
A structure for writing test drivers
JUnit features include:
Assertions for testing expected results
Sharing common test data among tests
Test suites for easily organizing and running tests
Test runners, both graphical and textual
JUnit is widely used in industry
Can be used as stand alone Java programs (from command line) or from an IDE such as IntelliJ or Eclipse
Introduction to Software Testing (Ch 1)
© Ammann & Offutt

25. JUnit Tests JUnit can be used to test …
… an entire object
… part of an object – method or interacting methods
… interaction between several objects
Primarily unit & integration testing, not system testing
Each test is embedded into one test method
A test class contains one or more test methods
Test classes include:
A test runner to run the tests - main()
A collection of test methods
Methods to set up the state before and update the state after each test and before and after all tests
Get started at junit.org
Introduction to Software Testing (Ch 1)
© Ammann & Offutt

26. Writing Tests for JUnit
Need to use methods of junit.framework.assert class
javadoc gives a complete description of its capabilities
Each test method checks a condition (assertion) and reports to the test runner whether the test succeeded or failed
The test runner uses the result to report to the user (in command line mode) or update the display (in an IDE)
All of the methods return void
A few representative methods (of junit.framework.assert):
assertTrue(boolean)
assertTrue(String, boolean)
assertEquals(Object, Object)
assertNull(Object)
Fail(String)
Introduction to Software Testing (Ch 1)
© Ammann & Offutt

27. Example JUnit Test Expected result The test public class Calc {
public long add (int a, int b)
return a + b; }
Expected result
import org.junit.Test;
import static org.junit.Assert.*;
public class calcTest {
private Calc calc;
@Test public void testAdd()
calc = new Calc ();
assertEquals((long) 5, calc.add(2,3)); }
The test
Introduction to Software Testing (Ch 1)
© Ammann & Offutt

28. Sample Assertions For a complete list, see
static void assertEquals(boolean expected, boolean actual)           Asserts that two booleans are equal
static void assertEquals(byte expected, byte actual)           Asserts that two bytes are equal
static void assertEquals(char expected, char actual)           Asserts that two chars are equal
static void assertEquals(int expected, int actual)           Asserts that two ints are equal
static void assertEquals(double expected, double actual, double delta)           Asserts that two doubles are equal, within a delta
static void assertEquals(float expected, float actual, float delta)           Asserts that two floats are equal, within a delta
For a complete list, see
Introduction to Software Testing (Ch 1)
© Ammann & Offutt

29. Junit DEMO (Tao Mo)

30. MP1 and MP2 Who to talk to about
Daejun Park: MP1 - Exercise 1 & 2 (Maven, JSP)
Tao Mo: MP1 - Exercise 3 (JDBC)
Yi Zhang: MP2

31. Selenium How do we test web applications?
Challenges: heterogeneity, dynamicity, security
Selenium
Tool set that automates web app testing across platforms
Can simulate user interactions in browser
Two components
Selenium IDE (has some limitations)
Selenium WebDriver (aka. Selenium 2)

32. Selenium DEMO (Yi Zhang)

33. MP1 and MP2 Who to talk to about
Daejun Park: MP1 - Exercise 1 & 2 (Maven, JSP)
Tao Mo: MP1 - Exercise 3 (JDBC)
Yi Zhang: MP2