What are User Interface Design and Operation oriented Metrics?

User interface design metrics are fine but above all else, be absolutely sure that your end users like the interface and are comfortable with the interactions required.
- Layout appropriateness is a design metric for human computer interface. The layout entities like graphic icons, text, menus, windows are used to assist the user.
- The cohesion metric for user interface measures the connection of on screen content to other on screen content. UI cohesion is high if data on screen belongs to single major data object. UI cohesion is low if different data are present and related to different data objects.
- The time required to achieve a scenario or operation, recover from an error, text density, number of data or content objects can be measured by direct measures of user interface interaction.

Operation oriented metrics are:
- Operation complexity is computed using complexity metrics because operations should be limited to a specific responsibility.
- Operation size depends on lines of code. As the number of messages sent by
a single operation increases, responsibilities have not been well allocated within a class.
- Average number of parameters per operation is defined as: larger the number of operation parameters, more complex is the relation between objects.

Aesthetic or Graphic Design - Layout Issues and Graphic Design Issues

Aesthetic or Graphic design makes the web application appealing, though it is functional in nature. It is an artistic angle that compliments the technical aspects of web engineering. To perform aesthetic design, web application users decide how they want the application to look like.

General Layout Guidelines To Consider When Screen Layout Is Designed

- Do not over crowd the web page with too much information as it makes it difficult for the suer to identify the needed information and it creates too much visual chaos.
- Scrolling on web page should be reduced as the users prefer not to scroll much. The best idea is to reduce the content or just put necessary content.
- The design should specify all layout items as a percentage of available space.
- There has to be a pattern that should be followed during group navigation, content and function geographically within the page.
- Web application should be designed in a way in which there is more emphasis on content. A typical web page should contain eighty percent of content with the remaining part dedicated to navigation and other features.
- Users have a tendency to scan the web page in a way they scan the page of a book i.e. from top-left to bottom right. High priority elements should be placed in upper-left portion of the page.

GRAPHIC DESIGN ISSUES

Graphic design begins with layout and then it covers the color schemes, sizes, styles, use of media, typefaces and all other aesthetic elements of an application.
Different web sites provide design tips and guidelines.

What are different tasks representing WebApp interface design?

The user interface design begins with
- identification of user.
- identification of task.
- identification of environmental requirements.
Once these are identified, user scenarios are created and analyzed.

TASKS REPRESENTING WEB APPLICATION INTERFACE DESIGN ARE:

- The information that is contained in the analysis model is reviewed and refined as required.
- A rough sketch of web application interface layout is developed.
- The user objectives should be mapped into specific interface actions.
- A set of user tasks associated with action should be defined.
- Each interface action should have a storyboard screen image which depicts the interface response to user interaction.
- The input from aesthetic design should be used to refine the interface layout and storyboards.
- Implementing interface requires user interface objects. These user interface objects should be identified which may require a search through an existing object library.
- A procedural representation of user's interaction with interface is developed.
- A behavioral representation of the interface is also developed. It may use UML state diagrams to represent state mechanisms.
- Each state's interface layout is described using design information developed in tasks 2 and tasks 5.
- The interface design model should be refined and reviewed.

Validation phase - Unit Testing - how to write Unit test cases

Preparing a Unit test case document commonly referred as UTC is an important task in unit testing activity. Having a complete UTC with every possible test case leads to complete unit testing and thus gives an assurance of defect free unit at the end of unit testing stage.

While preparing unit test cases the following aspects should be kept in mind-

Expected functionality
Write test cases against each functionality that is expected to be provided from the unit being developed. It is important that user requirements should be traceable to functional specifications which should be traceable to program specifications which should be traceable to unit test cases. Maintaining such traceability ensures that the application fulfills user requirements.

Input Values
- Write test cases for each of the inputs accepted by the unit. Every input has certain validation rule associated with it. Write test cases to validate this rule.
- There can be cross-field validations in which one field is enabled depending upon input of another field. Test cases for these should not be missed.
- Write test cases for the minimum and maximum values of input.
- Variables that hold data have their value limits. In case of computed fields, it is very important to write test cases to arrive at an upper limit value of the variables.
- Write test cases to check the arithmetic expressions with all possible combinations of values.

Output Values
- Write test cases to generate scenarios which will produce all types of output values that are expected from unit.

Screen Layout
Screen/report layout must be tested against the requirements. It should ensure that pages and screens are consistent.

Path Coverage
A unit may have conditional processing which results in various paths, the control can traverse through. Test cases must be written for each of these paths.

Assumptions and Transactions
A unit may assume certain things for it to function. Test cases must be written to check that the unit reports error if such assumptions are not met.
In case of database applications, test cases should be written to ensure that transactions are properly designed and in no way inconsistent data gets saved in the database.

Abnormal terminations and Error messages
Test cases should be written to test the behavior of unit in case of abnormal termination.
Error messages should be short, precise and self explanatory. They should be properly phrased and free of grammatical mistakes.