New_2_strategies.ppt

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  • By black-box testing we mean testing which is driven by the specification. This type of testing is typically done without using information from the internals of the software, focusing on inputs and expected outputs, it treats the software as a black-box, hence the name black-box testing. We list a few of the common black-box test design techniques.
  • New_2_strategies.ppt

    1. 1. Software Testing Testing Strategies
    2. 2. Software Testing Strategies <ul><li>First software quality assurance tools applied to control the software product's quality before its shipment </li></ul><ul><li>November 1994 survey by Perry </li></ul><ul><ul><li>24 % of project development budget was for testing </li></ul></ul><ul><ul><li>32 % of project management budget was for testing </li></ul></ul><ul><ul><li>27 % of project time was schedule for testing </li></ul></ul><ul><ul><li>(actually they allocate 45 % of their schedule time for testing) </li></ul></ul>
    3. 3. Outlines <ul><li>2.1 Introduction </li></ul><ul><ul><li>Testing Objectives </li></ul></ul><ul><li>2.2 Software Testing Strategies </li></ul><ul><li>2.3 Software Test Classifications </li></ul><ul><li>2.4 White Box Testing </li></ul><ul><li>2.5 Black Box Testing </li></ul>
    4. 4. Objective <ul><li>Explain testing objectives </li></ul><ul><li>Discuss the difference between the various testing strategies </li></ul><ul><li>Describe the concept of black box and white box testing </li></ul>
    5. 5. Outlines <ul><li>2.1 Introduction </li></ul><ul><ul><li>Testing Objectives </li></ul></ul><ul><li>2.2 Software Testing Strategies </li></ul><ul><li>2.3 Software Test Classifications </li></ul><ul><li>2.4 White Box Testing </li></ul><ul><li>2.5 Black Box Testing </li></ul>
    6. 6. Definition Revisited <ul><li>Myers </li></ul><ul><ul><li>Testing is the process of executing a program with intention of finding errors </li></ul></ul><ul><li>Paul Jorgensen </li></ul><ul><ul><li>Testing is obviously concerned with errors, faults, failures and incidents . A test is the act of exercising software with test cases with an objective of Finding failure and Demonstrate correct execution </li></ul></ul><ul><li>ISO </li></ul><ul><ul><li>Technical operation that consist of the determination of one or more characteristics of a given product, process or service according to a specified procedure </li></ul></ul>
    7. 7. What is the objectives of Software Testing?
    8. 8. Direct Objectives <ul><li>To identify and reveal as many errors as possible in the tested software </li></ul><ul><li>To bring the tested software, after correction of the identified errors and retesting to an acceptable level of quality </li></ul><ul><li>To perform the required tests efficiency and effectively, within budgetary and scheduling limitation </li></ul>
    9. 9. Indirect Objective <ul><li>To compile a record of software errors for use in error prevention (by corrective and preventive actions) </li></ul>
    10. 10. Outlines <ul><li>2.1 Introduction </li></ul><ul><ul><li>Testing Objectives </li></ul></ul><ul><li>2.2 Software Testing Strategies </li></ul><ul><li>2.3 Software Test Classifications </li></ul><ul><li>2.4 White Box Testing </li></ul><ul><li>2.5 Black Box Testing </li></ul>
    11. 11. Stages of Testing <ul><li>Module or unit testing. </li></ul><ul><li>Integration testing, </li></ul><ul><li>Function testing. </li></ul><ul><li>Performance testing. </li></ul><ul><li>Acceptance testing. </li></ul><ul><li>Installation testing. </li></ul>
    12. 12. Testing Strategies <ul><li>We began by 'testing-in-the-small' and move toward 'testing -in-the-large' </li></ul><ul><li>For conventional software </li></ul><ul><ul><li>The module (component) is our initial focus </li></ul></ul><ul><ul><li>Integration of module follows </li></ul></ul><ul><li>For OO software </li></ul><ul><ul><li>OO class that include attributes and operations and implies communication and collaboration </li></ul></ul>
    13. 13. Unit Testing <ul><li>Program reviews. </li></ul><ul><li>Formal verification. </li></ul><ul><li>Testing the program itself. </li></ul><ul><ul><li>black box and white box testing. </li></ul></ul>
    14. 14. Black Box or White Box? <ul><li>Maximum # of logic paths - determine if white box testing is possible. </li></ul><ul><li>Nature of input data. </li></ul><ul><li>Amount of computation involved. </li></ul><ul><li>Complexity of algorithms. </li></ul>
    15. 15. Unit Testing Details <ul><li>Interfaces tested for proper information flow. </li></ul><ul><li>Local data are examined to ensure that integrity is maintained. </li></ul><ul><li>Boundary conditions are tested. </li></ul><ul><li>Basis path testing should be used. </li></ul><ul><li>All error handling paths should be tested. </li></ul><ul><li>Drivers and/or stubs need to be developed to test incomplete software. </li></ul>
    16. 16. Generating Test Data <ul><li>Ideally want to test every permutation of valid and invalid inputs </li></ul><ul><li>Equivalence partitioning it often required to reduce to infinite test case sets </li></ul><ul><ul><li>Every possible input belongs to one of the equivalence classes. </li></ul></ul><ul><ul><li>No input belongs to more than one class. </li></ul></ul><ul><ul><li>Each point is representative of class. </li></ul></ul>
    17. 17. Integration Testing Strategies <ul><li>Test methodologies may vary but two basic testing strategies applied: </li></ul><ul><li>Test the software in its entirety </li></ul><ul><ul><li>“ Big Bang Testing” </li></ul></ul><ul><li>Test the software in modules - Unit Tests, Integration Tests, Systems Tests </li></ul><ul><ul><li>“ Incremental testing” </li></ul></ul><ul><li>Two strategies for incremental testing </li></ul><ul><ul><li>Bottom - up testing (test harness). </li></ul></ul><ul><ul><li>Top - down testing (stubs). </li></ul></ul><ul><li>Sandwich Testing </li></ul>
    18. 18. Top-Down Integration Testing <ul><li>Main program used as a test driver and stubs are substitutes for components directly subordinate to it. </li></ul><ul><li>Subordinate stubs are replaced one at a time with real components (following the depth-first or breadth-first approach). </li></ul><ul><li>Tests are conducted as each component is integrated. </li></ul><ul><li>On completion of each set of tests and other stub is replaced with a real component. </li></ul><ul><li>Regression testing may be used to ensure that new errors not introduced. </li></ul>
    19. 19. Top Down Integration <ul><li>Stub is a piece of code emulating a called function </li></ul>top module is tested with stubs stubs are replaced one at a time, &quot;depth first&quot; as new modules are integrated, some subset of tests is re-run A B C D E F G
    20. 20. Top down – Advantages & Disadvantages <ul><li>Top-down integration supports fault isolation; </li></ul><ul><li>Major design flaws show up early. Modules of a product can be divided into two groups: </li></ul><ul><ul><li>The logic modules and operational modules. </li></ul></ul><ul><ul><li>By coding and testing the logic modules before the operational modules, top-down integration will exploit any major design faults early in the development process </li></ul></ul><ul><li>The main disadvantage of top-down integration is that potentially reusable modules may not be adequately tested. </li></ul>
    21. 21. Bottom-Up Integration Testing <ul><li>Low level components are combined in clusters that perform a specific software function. </li></ul><ul><li>A driver (control program) is written to coordinate test case input and output. </li></ul><ul><li>The cluster is tested. </li></ul><ul><li>Drivers are removed and clusters are combined moving upward in the program structure. </li></ul>
    22. 22. Bottom-Up Integration <ul><li>a driver is a piece of code emulating a calling function </li></ul>drivers are replaced one at a time, &quot;depth first&quot; worker modules are grouped into builds and integrated A B C D E F G cluster
    23. 23. Bottom-up – Advantages & Disadvantages <ul><li>The operational modules are thoroughly tested when using a bottom-up strategy. It also provides fault-isolation, as does top-down integration. </li></ul><ul><li>Major design faults will be left undetected until late in the development, since the logic module are integrated last. </li></ul><ul><li>This may result in large costs in redesigning and recoding substantial portions of the project. </li></ul>
    24. 24. Sandwich Testing <ul><li>Combine the two so as to capitalize upon their strengths and minimize their weaknesses </li></ul><ul><li>neither top-down nor bottom-up inplemenetation/integration is suitable for all the modules, the solution is to partition them </li></ul>
    25. 25. Sandwich Testing Top modules are tested with stubs Worker modules are grouped into builds and integrated A B C D E F G cluster
    26. 26. Outlines <ul><li>2.1 Introduction </li></ul><ul><ul><li>Testing Objectives </li></ul></ul><ul><li>2.2 Software Testing Strategies </li></ul><ul><li>2.3 Software Test Classifications </li></ul><ul><li>2.4 White Box Testing </li></ul><ul><li>2.5 Black Box Testing </li></ul>
    27. 27. Software Test Classification <ul><li>Software test may be classified </li></ul><ul><ul><li>according to the testing concept or </li></ul></ul><ul><ul><li>to the requirement classification </li></ul></ul>
    28. 28. According to Testing Concept <ul><li>What concept to test? </li></ul><ul><ul><li>Output </li></ul></ul><ul><ul><ul><li>Output is used to archive an acceptable level of quality </li></ul></ul></ul><ul><ul><li>Structural of the software </li></ul></ul><ul><ul><ul><li>Internal structural and calculations involved is included for satisfactory testing </li></ul></ul></ul><ul><li>Two Classes have been developed </li></ul><ul><ul><li>Black box testing </li></ul></ul><ul><ul><ul><li>Identify bug according to software malfunctioning </li></ul></ul></ul><ul><ul><ul><li>Functionality testing </li></ul></ul></ul><ul><ul><li>White box testing </li></ul></ul><ul><ul><ul><li>Examine internal calculation paths in order to identify bug </li></ul></ul></ul><ul><ul><ul><li>Structural testing </li></ul></ul></ul>
    29. 29. According to Requirement <ul><li>The test id carried out to ensure full coverage of the respective requirement </li></ul><ul><ul><li>Operation </li></ul></ul><ul><ul><ul><li>Correctness, Reliability, Efficiency, Integrity, Usability </li></ul></ul></ul><ul><ul><li>Revision </li></ul></ul><ul><ul><ul><li>Maintainability, flexibility, testability </li></ul></ul></ul><ul><ul><li>Transition </li></ul></ul><ul><ul><ul><li>Portability, reusabilily, interoperability </li></ul></ul></ul><ul><li>From the requirement we can define the test classification </li></ul><ul><li>White box and black box can be used implemented respectively </li></ul>
    30. 30. Test Classification according to Requirement <ul><li>Correctness 1.1 Output correctness tests </li></ul><ul><ul><ul><ul><ul><li>1.2 Documentation tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.3 Availability tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.4 Data processing & calculations correctness tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.5 Software qualification tests </li></ul></ul></ul></ul></ul><ul><li>Reliability 2. Reliability tests </li></ul><ul><li>Efficiency 3. Stress test (load tests and durability tests) </li></ul><ul><li>Integrity 4. Software system security tests </li></ul><ul><li>Usability 5.1 Training usability tests </li></ul><ul><ul><ul><ul><li>5.2 Operational usability tests </li></ul></ul></ul></ul><ul><li>Maintainability 6. Maintainability tests </li></ul><ul><li>Flexibility 7. Flexibility tests </li></ul><ul><li>Testability 8. Testability tests </li></ul><ul><li>Portability 9. Portability tests </li></ul><ul><li>Re usability 10. Re usability tests </li></ul><ul><li>Interoperability 11.1 Software interoperability tests </li></ul><ul><ul><ul><ul><ul><li>11.2 Equipment interoperability test </li></ul></ul></ul></ul></ul>
    31. 31. Test Classification according to Requirement <ul><li>Correctness 1.1 Output correctness tests </li></ul><ul><ul><ul><ul><ul><li>1.2 Documentation tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.3 Availability tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.4 Data processing & calculations correctness tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.5 Software qualification tests </li></ul></ul></ul></ul></ul><ul><li>Reliability 2. Reliability tests </li></ul><ul><li>Efficiency 3. Stress test (load tests and durability tests) </li></ul><ul><li>Integrity 4. Software system security tests </li></ul><ul><li>Usability 5.1 Training usability tests </li></ul><ul><ul><ul><ul><li>5.2 Operational usability tests </li></ul></ul></ul></ul><ul><li>Maintainability 6. Maintainability tests </li></ul><ul><li>Flexibility 7. Flexibility tests </li></ul><ul><li>Testability 8. Testability tests </li></ul><ul><li>Portability 9. Portability tests </li></ul><ul><li>Re usability 10. Re usability tests </li></ul><ul><li>Interoperability 11.1 Software interoperability tests </li></ul><ul><ul><ul><ul><ul><li>11.2 Equipment interoperability test </li></ul></ul></ul></ul></ul>
    32. 32. <ul><li>Black box testing </li></ul><ul><li>Testing that ignores the internal mechanism of the system or component and focuses solely on the outputs in response to selected inputs and execution conditions </li></ul><ul><li>Testing conducted to evaluate the compliance of a system or component with specified functional requirements </li></ul><ul><li>White box testing </li></ul><ul><li>Testing that takes into account the internal mechanism of a system or component </li></ul>IEEE definitions
    33. 33. Outlines <ul><li>2.1 Introduction </li></ul><ul><ul><li>Testing Objectives </li></ul></ul><ul><li>2.2 Software Testing Strategies </li></ul><ul><li>2.3 Software Test Classifications </li></ul><ul><li>2.4 White Box Testing </li></ul><ul><li>2.5 Black Box Testing </li></ul>
    34. 34. White Box Testing <ul><li>White Box Testing requires verification of every program statement and comment </li></ul><ul><li>White box testing enables performance of </li></ul><ul><ul><li>Data processing and calculation correctness tests </li></ul></ul><ul><ul><ul><li>Every computation operation must be examined </li></ul></ul></ul><ul><ul><li>Software qualification tests, </li></ul></ul><ul><ul><ul><li>Software code (including comments) </li></ul></ul></ul><ul><ul><li>Maintainability test </li></ul></ul><ul><ul><ul><li>Failure causes detection, support adaption, software improvement </li></ul></ul></ul><ul><ul><li>Reusability test </li></ul></ul><ul><ul><ul><li>Reusable for future software packages </li></ul></ul></ul>
    35. 35. Data processing and calculation correctness tests <ul><li>Checking the operation by each test cases </li></ul><ul><ul><li>Different path </li></ul></ul><ul><ul><li>Which path is going to be tested? </li></ul></ul><ul><li>Two approaches </li></ul><ul><ul><li>Path coverage </li></ul></ul><ul><ul><ul><li>Path coverage of a test is measured by the percentage of all possible program paths included in planned testing. </li></ul></ul></ul><ul><ul><li>Line coverage </li></ul></ul><ul><ul><ul><li>Line coverage of a test is measured by the percentage of program code lines included in planned testing. </li></ul></ul></ul>
    36. 36. Path coverage <ul><li>Different path is created by condition statements </li></ul><ul><ul><li>IF-THEN-ELSE </li></ul></ul><ul><ul><li>DO-WHILE </li></ul></ul><ul><ul><li>DO-UNTIL </li></ul></ul><ul><li>Consider a simple module with 10 conditional statement allowing two options each </li></ul><ul><ul><li>Creates 2 10 different path = 1024 path </li></ul></ul><ul><ul><li>Examples: </li></ul></ul><ul><ul><ul><li>Taximeter </li></ul></ul></ul>
    37. 37. Taxi meter <ul><li>1. Minimal fare: $2. This fare covers the distance traveled up to 1000 yards and waiting time (stopping for traffic lights or traffic jams, etc.) of up to 3 minutes. </li></ul><ul><li>2. For every additional 250 yards or part of it: 25 cents. </li></ul><ul><li>3. For every additional 2 minutes of stopping or waiting or part thereof: 20 cents. </li></ul><ul><li>4. One suitcase: 0 change; each additional suitcase: $1. </li></ul><ul><li>5. Night supplement: 25%, effective for journeys between 21.00 and 06.00. </li></ul><ul><li>Regular clients are entitled to a 10% discount and are not charged the night supplement. </li></ul>
    38. 38. Flow Chart S ≤ 1 S >1 Yes WT ≤ 3 WT > 3 D ≤ 1000 1 Charge the minimal fare 2 Distance 5 Waiting time 14 Night journey? 11 Regular client? 3 6 4 12 13 16 15 17 Print receipt. 8 No.of suitcases 9 10 D > 1000 7 No No Yes
    39. 39. Examples <ul><li>24 different paths may be indicated </li></ul><ul><li>In order to archive full path coverage of the software module, we have to prepare at least 24 test cases </li></ul><ul><li>We need to find a minimum number of paths to cover all line of code </li></ul><ul><ul><li>Line coverage </li></ul></ul>
    40. 40. Flow Graph 3 6 9 12 5 2 1 8 11 15 4 17 7 16 10 13 14 R1 R2 R3 R5 R4 R6
    41. 41. The Minimum number of paths 3 6 9 12 5 2 1 8 11 15 4 17 7 16 10 13 14 R1 R2 R3 R5 R4 R6 Minimun 3 path is required
    42. 42. Advantages of White box Testing <ul><li>Advantages: </li></ul><ul><li>      * Direct determination of software correctness as expressed in the processing paths, including algorithms. </li></ul><ul><li>* Allows performance of line coverage follow up. </li></ul><ul><li>  * Ascertains quality of coding work and its adherence to coding standards. </li></ul><ul><li>Disadvantages : </li></ul><ul><li>  * The vast resources utilized, much above those required for black box testing of the same software package. </li></ul><ul><li>* The inability to test software performance in terms of availability (response time), reliability, load durability, etc. </li></ul>
    43. 43. Outlines <ul><li>2.1 Introduction </li></ul><ul><ul><li>Testing Objectives </li></ul></ul><ul><li>2.2 Software Testing Strategies </li></ul><ul><li>2.3 Software Test Classifications </li></ul><ul><li>2.4 White Box Testing </li></ul><ul><li>2.5 Black Box Testing </li></ul>
    44. 44. Test Classification according to Requirement <ul><li>Correctness 1.1 Output correctness tests </li></ul><ul><ul><ul><ul><ul><li>1.2 Documentation tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.3 Availability tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.4 Data processing & calculations correctness tests </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1.5 Software qualification tests </li></ul></ul></ul></ul></ul><ul><li>Reliability 2. Reliability tests </li></ul><ul><li>Efficiency 3. Stress test (load tests and durability tests) </li></ul><ul><li>Integrity 4. Software system security tests </li></ul><ul><li>Usability 5.1 Training usability tests </li></ul><ul><ul><ul><ul><li>5.2 Operational usability tests </li></ul></ul></ul></ul><ul><li>Maintainability 6. Maintainability tests </li></ul><ul><li>Flexibility 7. Flexibility tests </li></ul><ul><li>Testability 8. Testability tests </li></ul><ul><li>Portability 9. Portability tests </li></ul><ul><li>Re usability 10. Re usability tests </li></ul><ul><li>Interoperability 11.1 Software interoperability tests </li></ul><ul><ul><ul><ul><ul><li>11.2 Equipment interoperability test </li></ul></ul></ul></ul></ul>
    45. 45. Black Box Testing <ul><li>Apart from correctness tests(those 2), maintainability and re usability, most of other testing classes are unique to black box testing </li></ul><ul><ul><li>Explain the importance of black box testing </li></ul></ul><ul><li>However, due to the special characteristic of each testing strategy, black box testing cannot automatically substitute for white box testing </li></ul>
    46. 46. Black-Box Testing <ul><li>Black-box testing is testing from a functional or behavioral perspective to ensure a program meets its specification </li></ul><ul><li>Testing usually conducted without knowledge of software implementation - system treated as a “black box” </li></ul><ul><li>Black-box test design techniques include: </li></ul><ul><ul><li>equivalence partitioning, </li></ul></ul><ul><ul><li>boundary value analysis, </li></ul></ul><ul><ul><li>cause-effect graphing, </li></ul></ul><ul><ul><li>random testing </li></ul></ul>
    47. 47. How much testing is adequate? <ul><li>Completely validating IEEE 754 floating-point division requires 2 64 test-cases! </li></ul><ul><li>float divide(float x, float y) </li></ul><ul><li>From practical and economic perspectives, exhaustive testing is usually not possible </li></ul><ul><ul><li>Which software pieces should we test? </li></ul></ul><ul><ul><li>Which test cases should we choose? </li></ul></ul>
    48. 48. Equivalence class partitioning (EC) <ul><li>A black box method aimed at increasing the efficiency of testing and, at the same time, improving coverage of potential error conditions. </li></ul>
    49. 49. Boundary Value Analysis <ul><li>Based on experience / heuristics </li></ul><ul><ul><li>Testing boundary conditions of equivalence classes is more effective </li></ul></ul><ul><li>Choose input boundary values as equivalence classes representatives </li></ul><ul><li>Choose inputs that invoke output boundary values </li></ul><ul><li>Examples: </li></ul><ul><ul><li>(0, 10] ⇒ validate using 0, 1, 2, 9, 10, 11 </li></ul></ul><ul><ul><li>Read up to 5 elements ⇒ validate reading 0, 1, 4, 5, 6 elements </li></ul></ul>
    50. 50. BVA as an equivalence partitioning extension <ul><li>Choose one (or more) arbitrary value(s) in each equivalence class </li></ul><ul><li>Choose valid values exactly on lower and upper boundaries of equivalence class </li></ul><ul><li>Choose invalid values immediately below and above each boundary (if applicable) </li></ul>
    51. 51. Equivalence Class Partitioning (EC) <ul><li>An equivalence class (EC) is a set of input variable values that produce the same output results or that are processed identically. </li></ul><ul><li>EC boundaries are defined by a single numeric or alphabetic value, a group of numeric or alphabetic values, a range of values, and so on. </li></ul><ul><li>An EC that contains only valid states is defined as a &quot;valid EC,&quot; whereas an EC that contains only invalid states is defined as the &quot;invalid EC.&quot; </li></ul><ul><li>In cases where a program's input is provided by several variables, valid and invalid ECs should be defined for each variable. </li></ul>
    52. 52. Equivalence Class Partitioning (EC) <ul><li>According to the equivalence class partitioning method: </li></ul><ul><li>Each valid EC and each invalid EC are included in at least one test case. </li></ul><ul><li>Definition of test cases is done separately for the valid and invalid ECs. </li></ul>
    53. 53. Equivalence Class Partitioning (EC) <ul><li>In defining a test case for the valid ECs, we try to cover as many as possible “new” ECs in that same test case. </li></ul><ul><li>In defining invalid ECs, we must assign one test case to each “new” invalid EC, as a test case that includes more than one invalid EC may not allow the tester to distinguish between the program’s separate reactions to each of the invalid ECs. </li></ul><ul><li>Test cases are added as long as there are uncovered ECs. </li></ul>
    54. 54. Example – Ticket Price <ul><li>Ticket price depends on four variables </li></ul><ul><ul><li>Day (weekday, weekend) </li></ul></ul><ul><ul><li>Visitor's status (OT = one time, M = members) </li></ul></ul><ul><ul><li>Entry Hour (6 – 19, 19.01 – 24) </li></ul></ul><ul><ul><li>Visitor's age (up to 16, 16.01 – 60, 60.01 – 120) </li></ul></ul>
    55. 55. Entrance Ticket Price table
    56. 56. Test cases – The Ticket price
    57. 57. Advantage of Black Box Testing <ul><li>Advantages: </li></ul><ul><li>Allows us to carry out the majority of testing classes, most of which can be implemented solely by black box tests, i.e. load tests and availability tests. </li></ul><ul><li>For testing classes that can be carried out by both white and black box tests, black box testing requires fewer resources. </li></ul>
    58. 58. Disadvantages of Black Box Testing <ul><li>Disadvantages: </li></ul><ul><li>Possibility that coincidental aggregation of several errors will produce the correct response for a test case, and prevent error detection. </li></ul><ul><li>Absence of control of line coverage. There is no easy way to specify the parameters of the test cases required to improve coverage. </li></ul><ul><li>Impossibility of testing the quality of coding and its strict adherence to the coding standards. </li></ul>

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