Best Practices, Introduction to Testing, Junit Framework

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Best Practices, Introduction to Testing, J-unit
Framework

• CS2335
• Summer 2002

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Agenda

• Lab 5 Help after class
• Lab 6-9 Teams to me today
• Exam 2 July 8
• Lecture
• Best Practices
• Test Intro
• JUnit

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Miniature Milestones

• Problem Im 90 done.
• Technique
• Developers create their own estimate.
• Keep mini (no more than 1-2 days (hours))
• Milestones are 0/1
• Cover all tasks
• Use to cover short-term
• Assess and re-estimate frequently.
• Phase Project Management

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Change Board

• Problem Uncontrolled changes, lack of
  prioritization on bug fixes, Code/Fix cycle
• Technique
• Create a board of representatives
• Board has authority to accept/reject changes
• Changes are considered before they are made
• Side Effects are considered
• Phase Configuration Management

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Daily Smoke and Build Test

• Problem Unsuccessful Integration, low quality,
  poor progress visibility
• Technique
• All code modules turned in frequently.
• Developers keep code in buildable form.
• All interfaces are stubbed out.
• Smoke tests run automatically.
• Dummy code used where necessary.
• Breaking the build usually earns a prize.
• Phase Implementation, Code Integration

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Incremental Integration

• Problem Code integration fails. Big-bang
  approach frequently used. Excessive schedule
  spent in integration phase.
• Technique
• Use proven integration technique
• Top-down
• Bottom-up
• Hybrid
• Phase Integration

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Software Quality Assurance

• Process (Analysis, Design, Code, Test)
• Reviews/Inspections
• Multi-tiered Testing Strategy
• Configuration Control (Code/Docs)
• Standards Compliance
• Measurement/Reporting

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Software Quality Factors
Portability Reusability Interoperabilty
Maintainability Flexibility Testability
Correctness, Reliablity, Efficiency,
Integrity Usability
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Two Key Concepts

• Validation Are we building the right thing?
  Conformance to customer requirements and quality
  attributes.
• Verification Are we building the thing right?
  Process conformance, quality activities.

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Where does testing fit in?
PHASE O Testing Debugging
PHASE 1 Testing shows the software works
PHASE 2 Testing shows the software doesnt work
PHASE 3 Testing doesnt prove anything, it
reduces risk of unacceptable
software delivery.
PHASE 4 Testing is not an act, a mental
discipline of quality.
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The Testing Quote
Testing cannot show the absence of defects, it
can only show that software defects are present.
We cannot test quality into a product, we have to
design it in.
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Test Objectives

• Tests intended to find errors
• Good test cases have high p for finding a yet
  undiscovered error
• Successful tests cause program failure, i.e. find
  an undiscovered error.
• Minimal set of test cases needs to be developed
  because exhaustive testing not possible

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What we have here

• Developers do everything they can to make the
  software work.
• Testers do everything they can to make the
  software fail.

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Testing Paradox
Every method you use to prevent or find bugs
leaves a residue of subtler bugs against which
those methods are ineffective.
Cost
Defects Found
Time
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Testing Phases

• Unit
• Integration
• Component
• System
• Usability
• Regression
• Validation
• Alpha/Beta (FUT/OT)

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Vocabulary

• Test Case a set of data/events provided for a
  specific test.
• Test Suite a set of test cases.
• Test Driver a program written to test a unit
  module
• Test Stub a module written to test a higher
  level component
• Test Harness a test environment to run the stubs
  and drivers and check the results.

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Types of testing

• Structural (Whitebox)
• Functional (Blackbox)
• Statistical (Random)
• Mutation
• Object Oriented (State-based)
• Insert latest PhD thesis topic here

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Return of the Vocabulary

• Coverage a measure of the amount of testing to
  be achieved. Normally spoken of in standard
  criteria based upon test technique for a subset
  of test cases.
• Adequacy a measure of the overall efficiency and
  effectiveness of the test suite.

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Writing a test plan

• Introduction
• Purpose
• Program Description
• Test Environment
• Test Case Descriptions
• Coverage Criteria
• Details

4. Summary
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Stubbing Functions
int main (int argc, char argv) if (argclt4)
usage() double x f(argv1,argv2)
void usage() return double f(char
arg1, char arg2) return 3.0
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Writing Drivers
int main( int argc, char argv) int i
for (i0 ilt10i) printf(SQRT of i is
i, i, sqrt(i))
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Why does testing go bad?

• Schedule compression/ Waterfall
• Writing harnesses, suites,stubs and drivers
  doesnt relate directly to LOC.
• Different philosophys
• Overconfidence in silver bullets

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What is xUnit?

• An automated unit test framework
• Provides the Driver for unit(s)
• Provides automatic test runs
• Provides automatic result checks
• Available for multiple languages
• cppUnit
• sUnit
• Junit

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Junit Terms

• Failure Expected
• Error Unexpected
• TestCase Collection of method tests
• Test Fixture Object Reuse
• TestSuite Collection of Test Cases
• TestRunner Interface
• awt, swing,text

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Using Junit (Create Fixture)

• public class ComplexTest extends TestCase
• Complex c1
• Complex c2
• protected void setUp()
• c1 new Complex(7,3)
• c2 new Complex(12,6)
• protected void tearDown()

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Using Junit (Add Test Cases)

• public void testAdd()
• Complex result c1.Add(new Complex(5,3))
• assertEquals(result.get_r(),c2.get_r())
• assertEquals(result.get_i(),c2.get_i())
• public void testEqual()
• assertTrue(!c2.Equal(c1))
• assertTrue(c1.Equal(new Complex(7,3)))

assertNull, assertNotNull, assertSame
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Using Junit (Make Suite)

• public static Test suite()
• TestSuite suite new TestSuite()
• suite.addTest(new ComplexTest(testAdd))
• suite.addTest(new ComplexTest(testEqual))
• return suite

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Using Junit (Invoke)

• public static void main(String args)
• junit.textui.TestRunner.run(suite())
• public ComplexTest(String s)
• super(s)

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The Graphical UI
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UI on Failure
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What Junit does not do

• Figure out your tests for you
• Calculate any coverage criteria
• Test GUIs
• Except extensions
• JFCUnit
• Jemmy
• Pounder
• Abbot

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Administrative

• Download latest version (3.7) from
• www.junit.org
• Setup classpath to junit.jar
• Include appropriate ui in main
• Import junit.framework.

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Next Time

• Extreme Programming