Integration & System Testing potx

Integration & System Testing 2 Contents  Levels of Testing  Integration Testing  System Testing  Additional System Test Categories 3 Levels of Testing 4 Levels of Testing  Waterfall model Requirements Specification Preliminary Design Detailed Design Coding Unit Testing Integration Testing System Testing 5 Levels of Testing  Unit testing  Integration Testing  System Testing  Acceptance Testing  Regression Testing 6 Unit testing  Lowest Level of Testing  Individual unit of the software is tested in isolation from other parts of a program  What can be a unit?  Function / method / module / class / component  Screen / Program  Back-end related to a Screen  Screen + back end 7 Unit testing  Uncover errors in design and implementation, including  data structure in a unit  program logic and program structure in a unit  unit interface  functions and operations of a unit  Unit testers  developers of the units 8 Integration Testing  Intermediate level of testing  Group of dependent components are tested together  Test that evaluates the interaction and consistency of interacting components  Uncover errors in:  Design and construction of software architecture  Integrated functions or operations at sub-system level  Interfaces and interactions between them  Resource integration and/or environment integration  Integration testers  either developers and/or test engineers 9 System Testing  Test the whole system  Test end to end functionality  Testing against complete requirement  Requirement focus  Test cases derived from specification  System testers  test engineers 10 Acceptance Testing  User (or customer) involved  Environment as close to field use as possible  Focus on:  Building confidence  Compliance with defined acceptance criteria in the contract [...]... SATM 16 Example: SATM 17 Integration Testing 18 Goals of Integration Testing     Presumes previously tested units Not system testing (at level of system inputs and outputs) Tests functionality "between" unit and system levels Simulation of other components/units   Stubs receive output from test objects Drivers generate input to test objects 19 Approaches to Integration Testing  Based on Functional... Sandwich Pair-wise integration Neighborhood integration Based on Paths   MM-Paths Atomic System Functions 20 Integration Testing Based on Functional Decomposition  SATM Functional Decomposition Tree 21 Approaches to Integration Testing  Based on Functional Decomposition      Based on Call Graph    Big Bang Top-Down Bottom-Up Sandwich Pair-wise integration Neighborhood integration Based on...Regression Testing  Testing activities occur after software changes Regression testing usually refers to testing activities during software maintenance phase Retest changed components (or parts) Check the affected parts (or components)  Who perform regression testing       Developers - regression testing at the unit level or integration Test engineers - regression testing at the function... IS4 + 10 … 31 Sandwich Integration  Combination of top-down and bottom-up integration 32 Integration Testing Based on Call Graph 5 1 7 20 21 9 22 16 4 10 13 12 11 17 18 19 23 24 26 14 15 6 8 27 2 25 3 33 Approaches to Integration Testing  Based on Functional Decomposition      Based on Call Graph    Big Bang Top-Down Bottom-Up Sandwich Pair-wise integration Neighborhood integration Based on... engineers - regression testing at the function level QA and test engineers - regression testing at the system level 11 Example: SATM  Simple Automatic Teller Machine (SATM)  reduced commercial ATM system    hundreds of screens Has 15 screens Used to illustrate some testing approaches  Integartion testing, system testing 12 Example: SATM  Decomposed by screens                screen1... Drivers are removed and clusters are combined moving upward in the program structure Pros and cons of bottom-up integration:    no stubs cost need test drivers no controllable system until the last step 29 Bottom-up Integration 30 Bottom-up integration  Steps to test (IS : Integrated System)         Step 1: IS1 = 2 + 3 +4 (drivers: D’) Step 2: IS1 = IS1 + D (drivers: A’) Step 3: IS2 = 5... Neighborhood integration Based on Paths   MM-Paths Atomic System Functions 34 Pair-wise Integration   Eliminate the stub/driver development effort Instead, use the actual code    sounds like big bang integration but restrict a session to just a pair of units in the call graph one integration test session for each edge in the call graph 35 Pair-wise Integration 5 1 7 20 21 9 22 16 4 10 13 12 11 17 18... set of tests, another stub is replaced with the real module 5 Regression testing may conducted  Pros and cons top-down integration  stub construction cost  major control function can be tested early 25 Top-down integration 26 Top-down integration  Steps to test (IS : Integrated System)       Step 1: IS = 1 + A (stubs: D’, E’, 10’, B’, C’) Step 2: IS = IS + 10 (stubs: D’, E’, 10’, B’, C’, 11’,... integration Neighborhood integration Based on Paths   MM-Paths Atomic System Functions 22 Big bang Integration Combine (or integrate) all parts at once  Advantages   simple Disadvantages    hard to debugging, not easy to isolate errors not easy to validate test results impossible to form an integrated system 23 Top-down integration   Begins with the main program (the root of the tree) Needs... IS + D (stubs: E’, 10’, 11’, 12’, 13’, 14’, 15’, 16’, 17’, F’, 22’, 2’, 3’, 4’) Step 6: … 27 Bottom-up Integration    Starts with the leaves of the decomposition tree Then by moving upward through the control structure Needs the drivers  generate input to test objects 28 Bottom-up Integration  Integration process: 1 2 3 4  Low-level modules are combined into clusters that perform a specific software . Design Coding Unit Testing Integration Testing System Testing 5 Levels of Testing  Unit testing  Integration Testing  System Testing  Acceptance Testing  Regression Testing 6 Unit testing  Lowest. Integration & System Testing 2 Contents  Levels of Testing  Integration Testing  System Testing  Additional System Test Categories 3 Levels of Testing 4 Levels of Testing . SATM 18 Integration Testing 19 Goals of Integration Testing  Presumes previously tested units  Not system testing (at level of system inputs and outputs)  Tests functionality "between"