Unit-5

1. Unit-5 • Designing Interface Objects • Software Quality Assurance • System Usability • Measuring User Satisfaction

2. View Layer: Designing Interface Objects Objective • Identifying view Classes • Designing interface Objects

3. Goal of a User Interface (UI) To display and obtain needed information in an accessible,efficient manner.

4. The Purpose of a View Layer Interface Intro: • User interface can employ one or more Windows • Each window should serve a clear, specific purpose

5. The Purpose of a View Layer Interface (Cont) Purposes • Forms and data entry windows • Dialog boxes • Application windows

6. Forms and Data Entry Windows • Data entry windows provide access to data that users can retrieve, display and change in the application. • For example • Form Design in VB • Input Dialog boxes in VB

7. Example for Form Design

8. Example for Input Box

9. Forms and Data Entry Windows (Cont) Guidelines for designing Forms and Data Entry Window • Identify the information which we want to display or change • Identify the task that users need to work with data on the form or data entry window

10. Forms and Data Entry Windows (Cont) • Data entry tasks include • Navigating rows in a table, such as moving forward and backward, and going to the first and last record • Adding and deleting rows • Changing data in rows • Saving and canceling the changes We can provide buttons & menus to initiate the user tasks

11. Dialog Boxes Dialog boxes display status information or ask users to supply information or make a decision before continuing with a task • For example • Message Dialog boxes in VB • OK only • YES NO

12. Example for Dialog box

13. Dialog Boxes (Cont) Guidelines for designing Dialog boxes and Error messages A dialog box provides an exchange of information or a dialog between the user and the application Dialog boxes generally appear after a particular Menu item or a Command button pressed Error message If we will wrongly enter the date in the entry form then the message show the format for date (DD/MM/YYYY)

14. Guidelines for the Command Buttons Layout Position the command buttons are very important • Bottom • Align top right • Align left border is very popular in web interface

15. Application Windows( Main Window) An application window is a container of application objects or icons It contains an entire application with which users can interact

16. Application Windows (cont) Consist of Frame or border Title bar Scroll bars Menu bar Toll bar Status bar

17. Example

18. Application Windows (cont) File menu Open, Save, Save As, Print, Exit Edit Menu Cut, Copy, Paste View Menu Zoom,show and etc Help Menu Fonts Colors

19. Example

20. Example

21. Prototyping the user interface Activity diagram

22. VIEW LAYER:DESINGING INTERFACE OBJECTS Objectives: Identifying View Class Designing Interface Objects.

23. INTRODUCTION Two types of Interface • User Interface • Graphical User Interface

24. The main Goal of UI To display and obtain needed information in an accessible, efficient manner. The Main Goal of GUI Graphical Representation. • User Design as a Creative Process

25. View Objects Business Objects Access Objects Designing View Layer Classes • An implicit benefit of three layer Architecture. • Separation of the view layer from the business and access layer.

26. View Layer Objects They are the only exposed objects of an application with which users can interact. View Layer Class That represent the set of operations in the business that users must perform to Complete their task, Ideally in a way they find natural, Easy to remember, and Useful.

27. The View Layer Objects are represented for two major aspects of the applications. • INPUT – Responding to user interaction • OUTPUT-Display or Printing business objects.

28. View Layer Classes is divided four activities • Macro level UI design process. Identifying view layer objects, User’s perspective. • Micro level UI design activities. Design axioms and corollaries, Prototyping. • Testing usability and User satisfaction. • Refining and Iterating the design.

29. MACRO LEVEL PROCESS Two Steps: • For every class identified, determine if the class interacts with a human actor. 1.Identify the view (interface) objects for the class. 2. Define the relationship among the view objects. • Iterate and refine.

30. MICRO LEVEL PROCESS The process of designing view objects • For every interface object identified in the macro UI design process. • Iterate and Refine.

31. OBJECTIVE • QUALITY ASSURANCE TESTS • TESTING STRATEGIES • IMPACT OF OBJECT ORIENTATION ON TESTING • TEST CASES • TEST PLAN • CONTINUOUS TESTING • MYER’S DEBUGGING PRINCIPLES

32. QUALITY ASSURANCE TESTS Why? Computers are infamous for doing what you tell them to do, not necessarily what you want them to do. Debugging: Is the process of finding out where something went wrong and correcting the code to eliminate the errors or bugs that cause unexpected results. Types of Errors: • Language(syntax) errors • Run – time errors • Logic errors Categories: • Error – based Testing • Scenario(usage) – based Testing (contd…)

33. Categories • Error – based Testing. • Search for particular clues of interest. • Describe how clues should be tested. • Scenario – based Testing. • Concentrates on what the user does , not on what the product does. (contd…)

34. TESTING STRATEGIES • BLACK BOX TESTING • It is used to represent a system whose inside workings are not available for inspection. • WHITE BOX TESTING • Specific logic is important and must be tested to guarantee the systems proper functioning. • TOP – DOWN TESTING • It supports testing user interface and system integration. • BOTTOM – UP TESTING • It starts with the details of the system and proceeds to higher levels by a progressive aggregation of details until they fit requirements of system.

35. IMPACT OF OO ON TESTING • Errors. • Less Plausible ( not worth testing for ) • More Plausible ( worth testing for now ) • New • Impact of Inheritance on Testing. • Reusability of tests.

36. TEST CASES • A test case is a set of What – if questions. • To test a system you must construct some best input cases, that describe how the output will look. • Next, perform the tests and compare the outcome with the expected output. (contd…)

37. Myer’s (objective of testing ) • Testing Is a process of executing a program with the intent of finding errors. • Good test case That has a high probability of finding an as – yet – undiscovered error. • Successful test case That detects an as – yet – undiscovered error. (Contd…)

38. Guidelines (for preparing test cases.) • Describe the feature or service. • If based on use case, then refer its name. • Specify the feature to test and how to test. • Test the normal use. • Test the abnormal but reasonable use. • Test the abnormal and unreasonable use. • Test the boundary conditions. • While revising document the cases. • Reusability and extendibility should be assessed. • Add Questions that arise out of previous ones.

39. Test Plan • A Test plan is developed to detect and identify potential problems before delivering the software to its users. • A test plan offers a road map. • A dreaded and frequently overlooked activity in software development. • Steps: • Objectives of the test. • Development of a test case • Test analysis. • Regression Testing. • Beta Testing. • Alpha Testing. (contd…)

40. Guidelines (for preparing test plan) • Specify Requirements generated by user. • Specify Schedule and resources. • Determine the testing strategy. • Configuration Control System. • Keep the plan up to date. • At the end of each milestone, fill routine updates.

41. CONTINUOUS TESTING • Testing must take place on continuous basis and this refining cycle must continue throughout the development process until you are satisfied with the results. • During this iterative process, prototypes will be transformed incrementally into the actual application.

42. MYER’S DEBUGGING PRINCIPLES • Bug locating principles. • Think • If you reach an impasse, sleep on it. • If the impasse remains, describe the problem to someone else. • Use debugging tools. • Experimentation should be done as a last resort. • Debugging principles. • Where there is one bug , there is likely to be another. • Fix the error, not just the symptom. • The probability of solution being correct drops down as the size increases. • Beware of error correction, it may create new errors.

43. System Usability- Introduction • The task of satisfying user requirements is basic motivation of quality • Usability testing is different from quality assurance testing in that, rather finding programming defects. • It reflects the users need and satisfaction

44. USABILITY TESTING • Definition: • ISO Defines the usability as the effectiveness, efficiency and satisfaction with which a specified set of users to can achieve a specified set of tasks.

45. USABILITY TESTING • ISO Definition requires • Defining tasks – What are the tasks • Defining users – who are the users • A means for measuring effectiveness, efficiency and satisfaction – how do we measure usability

46. USABILITY TESTING • Usability measures the ease of use as well as the degree of comfort and satisfaction users have with the software. • Usability is one of the most crucial factor so it should begin in the earlier stage of product development.

47. USABILITY TESTING • Usability test cases begin with the identification of use cases. • When designing test focus on use cases and tasks not features.

48. USABILITY TESTING OOA- Use case model Quality assurance test cases User satisfaction Test cases Usability test cases Test plan Jacobson’s Life cycle model

49. Guidelines for Usability testing • The usability testing should involve all software components • Usability need not be more expensive or elaborate • All tests need not involve many subjects • Consider user’s experience as a part of your software usability • Apply usability testing early and often.

50. RECORDING THE USABILITY TEST • When conducting a usability test provide a comfortable environment. • Record the test results using a video camera or a tape recorder. • If possible involve all design team members in observing the test and reviewing the results.