Big Bang Approach No testing of Individual Units Advantages Cost can be saved No stubs/Drivers Very fast Disadvantages Hard to debug Location of defect may not be found easily Interface faults may not be distinguishable Testers use only few test cases

Sandwich Testing It combines bottom up and top down testing approach. A B C D G F E Layer I Layer II Layer III

Process of sandwich testing – Bottom up starts from middle and goes upwards – Top down starts from middle and goes downwards – Big bang in the middle layer Advantages – very large projects use this – Needs more resource and big team Disadvantages – High cost of testing – Cannot be used for small systems with huge interdependence

Critical path First In this one must define the critical path which represents the main function of a system(p1) This must be covered first in testing This is used where complete system testing is impossible and systems are so large. Subsystem testing Subsystem testing involves collection of units, submodules and modules which have been integrated to form subsystem

System testing System testing represents the final testing done on a system before it is delivered to the customer This testing goes through the following stages – Functional Testing: Finds whether all functions as per requirements are working or not – User Interface Testing: This involves colors, navigations, spellings and fonts.

Testing Stages Unit Testing Module Testing Subsystem Testing System Testing Acceptance Testing

Acceptance Testing is normally considered as the final stage of testing of an application. It validates – User needs are achieved – System performance meets the expectation of customer – Formal testing to determine whether the application satisfies the acceptance criteria

Acceptance Testing Characteristics – Final opportunity for buyer to examine the software w.r.t expectations – It is conducted in production environment – Incremental process of acceptance or rejection – Formal final acceptance – Test to determine whether developed system meets predefined criteria of acceptance Acceptance Testing Criteria This defines the criteria for acceptance or rejection of software. Rejection of good software – not qualified with the acceptance criteria and vice versa may also happen

Risk of Buyer: Risk faced by the buyer when he has to accept a bad product as it satisfies the acceptance criteria Risk to the seller: Risk faced by seller when Rejection of good software happens when it is not qualified with the acceptance criteria Importance of Acceptance Criteria It gives the information to customer about the expectation for the new system being developed. Refers to confidence level. Cost of acceptance has direct relationship with importance of a system.

Some famous Acceptance Criteria Hours of testing approach The application under acceptance is tested for certain time Number of test cases approach Customer define the test cases along with the test data to be executed as a part of acceptance testing Defect Density Approach function of processes used for developing and testing the product.

Probability Severity P1P2P3 S10510 S S Defect Density as per P-S matrix approach Allowable level of defects approach Total number of defects allowed or as per P-S matrix for number of defects allowed in each quadrant

Defect finding rate approach Coverage based acceptance criteria approach IterationDefect found per person day I(100 person days)5 II(100 person days)1 III(100 person days)0.2 IV(100 person days)0.05 V(100 person days)0.02 RequirementsCoverage P195% P250% P325%

Life cycle acceptance approach Each phase of a development life cycle gets formally accepted and approved by the customer before going to next phase. Thus, application is build right from the first step.

Alpha Testing Done by the customer at the developer site. Sometimes test data is provided by the customer while at other times data may be generated by mutually agreed techniques. Advantages: – Helps in training the key users – Fast way of getting approval from customer – Major changes about requirements can be initiated at this point – Improves the confidence that system can be delivered and used in production environment

Disadvantages – Data provided by the customer may not be the actual data – Lab experiments may not represent the real life environment – Key users may not be the real users and they do not address the key issues.

Beta Testing Done at user site with user environment by key users It affects the user environment directly Advantages – Gap between actual work environment – Training which is given during alpha testing may not be sufficient. – Ensures that application works in the real environment with live data Disadvantages – Actual users are not trained – Implied requirements may not be covered

Gamma Testing For the product to be launched in the market Product developed is given to the target users to receive the feedback. Success of gamma testing is to get users view about the new product. Advantages Helps in identifying the gap between market – research analyst Training required for users may be identified here Ensures that application works in the real environment with live data

Disadvantages – Actual users are not trained – Implied requirements may not be covered