1. Using UML, Patterns, and Java Object-Oriented Software Engineering Chapter 11: Testing

2. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 2 Outline  Terminology  Types of errors  Dealing with errors  Quality assurance vs Testing  Component Testing  Unit testing  Integration testing  Testing Strategy  Design Patterns & Testing  System testing  Function testing  Structure Testing  Performance testing  Acceptance testing  Installation testing

3. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 3 Terminology  Reliability: The measure of success with which the observed behavior of a system confirms to some specification of its behavior.  Failure: Any deviation of the observed behavior from the specified behavior.  Erroneous State: The system is in a state such that further processing by the system will lead to a failure.  Fault (Bug): The mechanical or algorithmic cause of an error. There are many different types of errors and different ways how we can deal with them.

4. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 4 Examples of Faults and Errors  Faults in the Interface specification  Mismatch between what the client needs and what the server offers  Mismatch between requirements and implementation  Algorithmic Faults  Missing initialization  Branching errors (too soon, too late)  Missing test for nil  Faults in the Interface specification  Mismatch between what the client needs and what the server offers  Mismatch between requirements and implementation  Algorithmic Faults  Missing initialization  Branching errors (too soon, too late)  Missing test for nil  Mechanical Faults (very hard to find)  Documentation does not match actual conditions or operating procedures  Errors  Stress or overload errors  Capacity or boundary errors  Timing errors  Throughput or performance errors  Mechanical Faults (very hard to find)  Documentation does not match actual conditions or operating procedures  Errors  Stress or overload errors  Capacity or boundary errors  Timing errors  Throughput or performance errors

5. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 5 Dealing with Faults  Fault avoidance (without execution):  Use good programming methodology  Use version control to prevent inconsistent system  Perform inspections and verification to catch algorithmic bugs  Fault detection (through system execution):  Testing: Create failures in a planned way  Debugging: Start with an unplanned failures  Monitoring: Deliver information about state. Find performance bugs  Fault tolerance (recover from failure once the system is released):  Data base systems (atomic transactions)  Modular redundancy  Recovery blocks

6. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 6 Testing  Testing is NOT the process of demonstrating that faults are not present.  Testing is the systematic method of detecting faults by creating failures and erroneous states in a planned way.  It is impossible to completely test any nontrivial module or any system  Testing can only show the presence of bugs, not their absence (Dijkstra)  Other validation methods:  Inspections and reviews detect faults by using a structured approach to reading the code and design artifacts.  Formal verification detects faults through mathematical proofs of correctness.

7. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 7 Testing takes creativity  Testing often viewed as dirty work.  To develop an effective test, one must have:  Detailed understanding of the system  Knowledge of the testing techniques  Skill to apply these techniques in an effective and efficient manner  Testing is done best by independent testers  We often develop a certain mental attitude that the program should in a certain way when in fact it does not.  Programmer often stick to the data set that makes the program work  "Don’t mess up my code!"  A program often does not work when tried by somebody else.  Don't let this be the end-user.

8. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 8 Testing Activities Tested Subsystem Code Functional Integration Unit Tested Subsystem Requirements Analysis Document System Design Document Tested Subsystem Test Test Unit Test Unit Test User Manual Requirements Analysis Document Subsystem Code Subsystem Code All tests by developer Functioning System Integrated Subsystems

9. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 9 Global Requirements Testing Activities continued User’s understanding Tests by developer PerformanceAcceptance Client’s Understanding of Requirements Test Functioning System Test Installation User Environment Test System in Use Usable System Validated System Accepted System Tests (?) by user Tests by client

10. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 10 Fault Handling Techniques Testing Fault Handling Fault Avoidance Fault Tolerance Fault Detection Debugging Unit Testing Integration Testing System Testing Verification Configuration Management Atomic Transactions Modular Redundancy Correctness Debugging Performance Debugging Reviews Design Methodology

11. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 11 Quality Assurance encompasses Testing Usability Testing Quality Assurance Testing Prototype Testing Scenario Testing Product Testing Fault AvoidanceFault Tolerance Fault Detection Debugging Unit Testing Integration Testing System Testing Verification Configuration Management Atomic Transactions Modular Redundancy Correctness Debugging Performance Debugging Reviews WalkthroughInspection

12. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 12 Design and Code Review or Inspection  A formalized procedure for reading design and code artifacts with the purpose of detecting faults.  Involves a team of developers in the role of reviewers.  Traditional steps:  Preparation – reviewers become familiar with the design or code and record any issues found in the process  Meeting – a reader paraphrases the design or code and the reviewers raise issues as the reader proceeds at a measured reading rate; a moderator controls the pace of the meeting and keeps discussions focused  Rework – the author resolves the issues and repairs the faults  Follow-up – the moderator checks the rework and determines the disposition of the inspection (accept, accept with fixes, re-review)  Inspections are usually done at the unit or component level  Inspections complement unit testing as they tend to find different types of faults

13. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 13 Types of Testing  Unit Testing:  Individual subsystem  Carried out by developers  Goal: Confirm that subsystems is correctly coded and carries out the intended functionality  Integration Testing:  Groups of subsystems (collection of classes) and eventually the entire system  Carried out by developers  Goal: Test the interface among the subsystem

14. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 14 System Testing  System Testing:  The entire system  Carried out by developers  Goal: Determine if the system meets the requirements (functional and global)  Acceptance Testing:  Evaluates the system delivered by developers  Carried out by the client. May involve executing typical transactions on site on a trial basis  Goal: Demonstrate that the system meets customer requirements and is ready to use  Implementation (Coding) and testing go hand in hand

15. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 15 Unit Testing  Informal:  Incremental coding  Static Analysis:  Hand execution: Reading the source code  Walk-Through (informal presentation to others)  Code Inspection (formal presentation to others)  Automated Tools checking for  syntactic and semantic errors  departure from coding standards  Dynamic Analysis:  Black-box testing (Test the input/output behavior)  White-box testing (Test the internal logic of the subsystem or object)  Data-structure based testing (Data types determine test cases)

16. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 16 Black-box Testing  Focus: I/O behavior. If for any given input, we can predict the output, then the module passes the test.  Almost always impossible to generate all possible inputs ("test cases")  Goal: Reduce number of test cases by equivalence partitioning:  Divide input conditions into equivalence classes  Choose test cases for each equivalence class. (Example: If an object is supposed to accept a negative number, testing one negative number is enough)

17. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 17 Black-box Testing (Continued)  Selection of equivalence classes (No rules, only guidelines):  Input is valid across range of values. Select test cases from 3 equivalence classes:  Below the range  Within the range  Above the range  Input is valid if it is from a discrete set. Select test cases from 2 equivalence classes:  Valid discrete value  Invalid discrete value  Another solution to select only a limited amount of test cases:  Get knowledge about the inner workings of the unit being tested => white-box testing

18. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 18 White-box Testing  Focus: Thoroughness (Coverage). Every statement in the component is executed at least once.  Types of white-box testing  Statement Testing  Loop Testing  Path Testing  Branch Testing  State-based Testing

19. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 19 if ( i =TRUE) printf("YES\n");else printf("NO\n"); Test cases: 1) i = TRUE; 2) i = FALSE White-box Testing (Continued)  Statement Testing (Algebraic Testing): Test single statements (Choice of operators in polynomials, etc)  Loop Testing:  Cause execution of the loop to be skipped completely. (Exception: Repeat loops)  Loop to be executed exactly once  Loop to be executed more than once  Path testing:  Make sure all paths in the program are executed  Branch Testing (Conditional Testing): Make sure that each possible outcome from a condition is tested at least once

20. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 20 /*Read in and sum the scores*/ White-box Testing Example FindMean(float Mean, FILE ScoreFile) { SumOfScores = 0.0; NumberOfScores = 0; Mean = 0; Read(ScoreFile, Score); while (! EOF(ScoreFile) { if ( Score > 0.0 ) { SumOfScores = SumOfScores + Score; NumberOfScores++; } Read(ScoreFile, Score); } /* Compute the mean and print the result */ if (NumberOfScores > 0 ) { Mean = SumOfScores/NumberOfScores; printf("The mean score is %f \n", Mean); } else printf("No scores found in file\n"); }

21. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 21 White-box Testing Example: Determining the Paths FindMean (FILE ScoreFile) { float SumOfScores = 0.0; int NumberOfScores = 0; float Mean=0.0; float Score; Read(ScoreFile, Score); while (! EOF(ScoreFile) { if (Score > 0.0 ) { SumOfScores = SumOfScores + Score; NumberOfScores++; } Read(ScoreFile, Score); } /* Compute the mean and print the result */ if (NumberOfScores > 0) { Mean = SumOfScores / NumberOfScores; printf(“ The mean score is %f\n”, Mean); } else printf (“No scores found in file\n”); } 1 2 3 4 5 7 6 8 9

22. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 22 Constructing the Logic Flow Diagram

23. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 23 Finding the Test Cases Start 2 3 4 5 6 7 8 9 Exit 1 b d e g f i j h c kl a (Covered by any data) (Data set must (Data set must contain at least one value) be empty) (Total score > 0.0) (Total score < 0.0) (Positive score) (Negative score) (Reached if either f or e is reached)

24. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 24 Test Cases  Test case 1 : ? (To execute loop exactly once)  Test case 2 : ? (To skip loop body)  Test case 3: ?,? (to execute loop more than once)  These 3 test cases cover all control flow paths

25. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 25 Dealing with Polymorphism  Polymorphism enables invocations to be bound to different methods based on the class of the target  Leads to compact code and increased reuse  Introduces many new cases to test  Strategy  Consider all possible dynamic bindings and convert the invocation into an if-then-else statement for each potential dynamic binding  Perform path testing

26. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 26 State-Based Testing  Instead of comparing actual and expected outputs, state-based testing compares resulting state with expected state  Each test case consists of starting state, stimuli, expected next state  Useful for classes with complex state transition diagrams  Steps  Derive test cases from the statechart model  For each state, derive equivalence classes of stimuli to activate each transition  Instrument each attribute of the class in order to compute the new state of the class

27. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 27 Example Statechart Diagram MeasureTime SetTime 3.pressButtonsLAndR 5.pressButtonsLAndR/beep 4.after 2 min. DeadBattery 8.after 20 years7.after 20 years 1. pressButtonL pressButtonR 2. pressButtonL pressButtonR 6.

28. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 28 Comparison of White & Black-box Testing  White-box Testing:  Potentially infinite number of paths have to be tested  White-box testing often tests what is done, instead of what should be done  Cannot detect missing use cases  Black-box Testing:  Potential combinatorical explosion of test cases (valid & invalid data)  Often not clear whether the selected test cases uncover a particular error  Does not discover extraneous use cases ("features")  Both types of testing are needed  White-box testing and black box testing are the extreme ends of a testing continuum.  Any choice of test case lies in between and depends on the following:  Number of possible logical paths  Nature of input data  Amount of computation  Complexity of algorithms and data structures

29. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 29 The 4 Testing Steps 1. Select what has to be measured  Analysis: Completeness of requirements  Design: tested for cohesion  Implementation: Code tests 2. Decide how the testing is done  Code inspection  Proofs (Design by Contract)  Black-box, white box,  Select integration testing strategy (big bang, bottom up, top down, sandwich) 1. Select what has to be measured  Analysis: Completeness of requirements  Design: tested for cohesion  Implementation: Code tests 2. Decide how the testing is done  Code inspection  Proofs (Design by Contract)  Black-box, white box,  Select integration testing strategy (big bang, bottom up, top down, sandwich) 3. Develop test cases  A test case is a set of test data or situations that will be used to exercise the unit (code, module, system) being tested or about the attribute being measured 4. Create the test oracle  An oracle contains of the predicted results for a set of test cases  The test oracle has to be written down before the actual testing takes place 3. Develop test cases  A test case is a set of test data or situations that will be used to exercise the unit (code, module, system) being tested or about the attribute being measured 4. Create the test oracle  An oracle contains of the predicted results for a set of test cases  The test oracle has to be written down before the actual testing takes place

30. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 30 Guidance for Test Case Selection  Use analysis knowledge about functional requirements (black-box testing):  Use cases  Expected input data  Invalid input data  Use design knowledge about system structure, algorithms, data structures (white-box testing):  Control structures  Test branches, loops,...  Data structures  Test records fields, arrays,...  Use analysis knowledge about functional requirements (black-box testing):  Use cases  Expected input data  Invalid input data  Use design knowledge about system structure, algorithms, data structures (white-box testing):  Control structures  Test branches, loops,...  Data structures  Test records fields, arrays,...  Use implementation knowledge about algorithms:  Examples:  Force division by zero  Use sequence of test cases for interrupt handler  Use implementation knowledge about algorithms:  Examples:  Force division by zero  Use sequence of test cases for interrupt handler

31. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 31 Unit-testing Heuristics 1. Create unit tests as soon as object design is completed:  Black-box test: Test the use cases & functional model  White-box test: Test the dynamic model  Data-structure test: Test the object model 2. Develop the test cases  Goal: Find the minimal number of test cases to cover as many paths as possible 3. Cross-check the test cases to eliminate duplicates  Don't waste your time! 1. Create unit tests as soon as object design is completed:  Black-box test: Test the use cases & functional model  White-box test: Test the dynamic model  Data-structure test: Test the object model 2. Develop the test cases  Goal: Find the minimal number of test cases to cover as many paths as possible 3. Cross-check the test cases to eliminate duplicates  Don't waste your time! 4. Desk check your source code  Reduces testing time 5. Create a test harness  Test drivers and test stubs are needed for integration testing 6. Describe the test oracle  Often the result of the first successfully executed test 7. Execute the test cases  Don’t forget regression testing  Re-execute test cases every time a change is made. 8. Compare the results of the test with the test oracle  Automate as much as possible 4. Desk check your source code  Reduces testing time 5. Create a test harness  Test drivers and test stubs are needed for integration testing 6. Describe the test oracle  Often the result of the first successfully executed test 7. Execute the test cases  Don’t forget regression testing  Re-execute test cases every time a change is made. 8. Compare the results of the test with the test oracle  Automate as much as possible

32. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 32 Integration Testing Strategy  The entire system is viewed as a collection of subsystems (sets of classes) determined during the system and object design.  The order in which the subsystems are selected for testing and integration determines the testing strategy  Big bang integration (Nonincremental)  Bottom up integration  Top down integration  Sandwich testing  Variations of the above  For the selection use the system decomposition from the System Design

33. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 33 Using the Bridge Pattern to enable early Integration Testing  Use the bridge pattern to provide multiple implementations under the same interface.  Interface to a component that is incomplete, not yet known or unavailable during testing VIP Seat Interface (in Vehicle Subsystem) Seat Implementation Stub Code Real Seat Simulated Seat (SA/RT)

34. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 34 Example: Three Layer Call Hierarchy A B C D G F E Layer I Layer II Layer III

35. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 35 Integration Testing: Big-Bang Approach Unit Test F Unit Test E Unit Test D Unit Test C Unit Test B Unit Test A System Test Don’t try this!

36. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 36 Bottom-up Testing Strategy  The subsystem in the lowest layer of the call hierarchy are tested individually  Then the next subsystems are tested that call the previously tested subsystems  This is done repeatedly until all subsystems are included in the testing  Special program needed to do the testing, Test Driver:  A routine that calls a subsystem and passes a test case to it

37. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 37 Bottom-up Integration A B C D G F E Layer I Layer II Layer III Test F Test E Test G Test C Test D,G Test B, E, F Test A, B, C, D, E, F, G

38. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 38 Pros and Cons of bottom up integration testing  Tests some important subsystems (user interface) last  Useful for integrating the following systems  Object-oriented systems  real-time systems  systems with strict performance requirements

39. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 39 Top-down Testing Strategy  Test the top layer or the controlling subsystem first  Then combine all the subsystems that are called by the tested subsystems and test the resulting collection of subsystems  Do this until all subsystems are incorporated into the test  Special program is needed to do the testing, Test stub :  A program or a method that simulates the activity of a missing subsystem by answering to the calling sequence of the calling subsystem and returning back fake data. SeatDriver (simulates VIP) Seat Interface (in Vehicle Subsystem) Seat Implementation Stub Code Real Seat Simulated Seat (SA/RT)

40. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 40 Top-down Integration Testing A B C D G F E Layer I Layer II Layer III Test A Layer I Test A, B, C, D Layer I + II Test A, B, C, D, E, F, G All Layers

41. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 41 Pros and Cons of top-down integration testing  Test cases can be defined in terms of the functionality of the system (functional requirements)  Writing stubs can be difficult: Stubs must allow all possible conditions to be tested.  Possibly a very large number of stubs may be required, especially if the lowest level of the system contains many methods.  One solution to avoid too many stubs: Modified top-down testing strategy  Test each layer of the system decomposition individually before merging the layers  Disadvantage of modified top-down testing: Both, stubs and drivers are needed

42. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 42 Sandwich Testing Strategy  Combines top-down strategy with bottom-up strategy  The system is view as having three layers  A target layer in the middle  A layer above the target  A layer below the target  Write drivers and stubs for target layer  Testing converges at the target layer  How do you select the target layer if there are more than 3 layers?  Heuristic: Try to minimize the number of stubs and drivers

43. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 43 Sandwich Testing Strategy A B C D G F E Layer I Layer II Layer III Test E Test D,G Test B, E, F Test A, B, C, D, E, F, G Test F Test G Test A Bottom Layer Tests Top Layer Tests Test A,B,C, D

44. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 44 Pros and Cons of Sandwich Testing  Top and Bottom Layer Tests can be done in parallel  Does not test the individual subsystems thoroughly before integration  Solution: Modified sandwich testing strategy

45. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 45 Modified Sandwich Testing Strategy  Test in parallel:  Middle layer with drivers and stubs  Top layer with stubs  Bottom layer with drivers  Test in parallel:  Top layer accessing middle layer (top layer replaces drivers)  Bottom accessed by middle layer (bottom layer replaces stubs)

46. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 46 Modified Sandwich Testing Strategy A B C D G F E Layer I Layer II Layer III Test F Test E Test B Test G Test DTest A Test C Test B, E, F Triple Test I Triple Test I Triple Test I Triple Test I Test D,G Double Test II Double Test II Double Test II Double Test II Double Test I Double Test I Double Test I Double Test I Test A,C Test A, B, C, D, E, F, G

47. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 47 Scheduling Sandwich Tests: Example of a Dependency Chart Unit Tests Double Tests Triple Tests SystemTests

48. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 48 Steps in Integration-Testing. 1. Based on the integration strategy, select a component to be tested. Unit test all the classes in the component. 2. Put selected component together; do any preliminary fix-up necessary to make the integration test operational (drivers, stubs) 3. Do functional testing: Define test cases that exercise all uses cases with the selected component 1. Based on the integration strategy, select a component to be tested. Unit test all the classes in the component. 2. Put selected component together; do any preliminary fix-up necessary to make the integration test operational (drivers, stubs) 3. Do functional testing: Define test cases that exercise all uses cases with the selected component 4. Do structural testing: Define test cases that exercise the selected component 5. Execute performance tests 6. Keep records of the test cases and testing activities. 7. Repeat steps 1 to 7 until the full system is tested. The primary goal of integration testing is to identify errors in the (current) component configuration. 4. Do structural testing: Define test cases that exercise the selected component 5. Execute performance tests 6. Keep records of the test cases and testing activities. 7. Repeat steps 1 to 7 until the full system is tested. The primary goal of integration testing is to identify errors in the (current) component configuration.

49. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 49 Which Integration Strategy should you use?  Factors to consider  Amount of test harness (stubs &drivers)  Location of critical parts in the system  Availability of hardware  Availability of components  Scheduling concerns  Bottom up approach  good for object oriented design methodologies  Test driver interfaces must match component interfaces ...  Factors to consider  Amount of test harness (stubs &drivers)  Location of critical parts in the system  Availability of hardware  Availability of components  Scheduling concerns  Bottom up approach  good for object oriented design methodologies  Test driver interfaces must match component interfaces ... ...Top-level components are usually important and cannot be neglected up to the end of testing  Detection of design errors postponed until end of testing  Top down approach  Test cases can be defined in terms of functions examined  Need to maintain correctness of test stubs  Writing stubs can be difficult ...Top-level components are usually important and cannot be neglected up to the end of testing  Detection of design errors postponed until end of testing  Top down approach  Test cases can be defined in terms of functions examined  Need to maintain correctness of test stubs  Writing stubs can be difficult

50. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 50 System Testing  Functional Testing  Structure Testing  Performance Testing  Acceptance Testing  Installation Testing Impact of requirements on system testing:  The more explicit the requirements, the easier they are to test.  Quality of use cases determines the ease of functional testing  Quality of subsystem decomposition determines the ease of structure testing  Quality of nonfunctional requirements and constraints determines the ease of performance tests:

51. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 51 Structure Testing  Essentially the same as white box testing.  Goal: Cover all paths in the system design  Exercise all input and output parameters of each component.  Exercise all components and all calls (each component is called at least once and every component is called by all possible callers.)  Use conditional and iteration testing as in unit testing.

52. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 52 Functional Testing.. Essentially the same as black box testing  Goal: Test functionality of system  Test cases are designed from the requirements analysis document (better: user manual) and centered around requirements and key functions (use cases)  The system is treated as black box.  Unit test cases can be reused, but user-oriented test cases have to be developed as well.

53. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 53 Performance Testing  Stress Testing  Stress limits of system (maximum # of users, peak demands, extended operation )  Volume testing  Test what happens if large amounts of data are handled  Configuration testing  Test the various software and hardware configurations  Compatibility test  Test backward compatibility with existing systems  Security testing  Try to violate security requirements  Timing testing  Evaluate response times and time to perform a function  Environmental test  Test tolerances for heat, humidity, motion, portability  Quality testing  Test reliability, maintain- ability & availability of the system  Recovery testing  Tests system’s response to presence of errors or loss of data.  Human factors testing  Tests user interface with user

54. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 54 Test Cases for Performance Testing  Push the (integrated) system to its limits.  Goal: Try to break the subsystem  Test how the system behaves when overloaded.  Can bottlenecks be identified? (First candidates for redesign in the next iteration  Try unusual orders of execution  Call a receive() before send()  Check the system’s response to large volumes of data  If the system is supposed to handle 1000 items, try it with 1001 items.  What is the amount of time spent in different use cases?  Are typical cases executed in a timely fashion?

55. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 55 Acceptance Testing  Goal: Demonstrate system is ready for operational use  Choice of tests is made by client/sponsor  Many tests can be taken from integration testing  Acceptance test is performed by the client, not by the developer.  Majority of all bugs in software is typically found by the client after the system is in use, not by the developers or testers. Therefore two kinds of additional tests:  Goal: Demonstrate system is ready for operational use  Choice of tests is made by client/sponsor  Many tests can be taken from integration testing  Acceptance test is performed by the client, not by the developer.  Majority of all bugs in software is typically found by the client after the system is in use, not by the developers or testers. Therefore two kinds of additional tests:  Alpha test:  Sponsor uses the software at the developer’s site.  Software used in a controlled setting, with the developer always ready to fix bugs.  Beta test:  Conducted at sponsor’s site (developer is not present)  Software gets a realistic workout in target environ- ment  Potential customer might get discouraged  Alpha test:  Sponsor uses the software at the developer’s site.  Software used in a controlled setting, with the developer always ready to fix bugs.  Beta test:  Conducted at sponsor’s site (developer is not present)  Software gets a realistic workout in target environ- ment  Potential customer might get discouraged

56. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 56 Testing has its own Life Cycle Establish the test objectives Design the test cases Write the test cases Test the test cases Execute the tests Evaluate the test results Change the system Do regression testing

57. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 57 Test Team Test Analyst Team User Programmer too familiar with code Professional Tester Configuration Management Specialist System Designer

58. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 58 Test Plan  Introduction  Relationship to other documents  System overview (overview of components, esp. for unit test)  Test coverage (features to be tested/not to be tested)  Pass/Fail criteria  Approach  Suspension and resumption  Testing materials (hardware/software requirements)  Test cases  Testing schedule

59. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 59 Test Case Specification  Test case specification identifier  Test items  Input specifications  Output specifications  Environmental needs  Special procedural requirements  Intercase dependencies

60. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 60 Test Automation  Regression testing – re-running system and integration tests to verify that changes to the system do not lead to new failures and erroneous states.  In practice, many tests need to be repeatedly run as part of regression testing.  Test automation can save a significant amount of testing effort and staff needs.  Test cases – specified in terms of sequence of inputs and their expected outputs  Test harness – automatically executes the test cases and compares actual output with expected output  This requires an investment to develop.

61. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 61 Automated Test Infrastructure Example: JUnit Test TestCaseTestSuite TestResult run(TestResult) setUp() tearDown() testName:String run(TestResult) runTest() run(TestResult) addTest() ConcreteTestCase setUp() tearDown() runTest()

62. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 62 Automated Test Infrastructure Example: JUnit

63. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 63 Using JUnit  Write new test case by subclassing from TestCase  Implement setUp() and tearDown() methods to initialize and clean up  Implement runTest() method to run the test harness and compare actual with expected values  Test results are recorded in TestResult  A collection of tests can be stored in TestSuite.

64. Modified from Bruegge & Dutoit’s originals Object-Oriented Software Engineering: Using UML, Patterns, and Java 64 Summary  Testing is still a black art, but many rules and heuristics are available  Testing consists of component-testing ( unit testing, integration testing) and system testing  Design Patterns can be used for integration testing  Testing has its own lifecycle  Testing is still a black art, but many rules and heuristics are available  Testing consists of component-testing ( unit testing, integration testing) and system testing  Design Patterns can be used for integration testing  Testing has its own lifecycle