1. Chapter 11: Testing, Testing…1, 2, 3
(Selecting Test Data)

2. Chapter Objectives After studying Chapter 11, you should be able to:
Select appropriate test data for an application
Prevent the entry of unwanted characters in a text box
Create a message box with the MessageBox.Show method
Trim leading and trailing spaces from a string
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

3. Will Your Application Pass the Test?
Test a program using both valid and invalid data
Valid data is data that the program is expecting the user to enter
Invalid data is data that the program is not expecting the user to enter
Invalid data typically is the result of the user making a typing error, entering the data in an incorrect format, or neglecting to make a required entry
Figure 11-1 Guidelines for selecting an application’s test data
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

4. The Coffee Palace- Version 1 Application
The interface provides a text box for entering the number of pounds of coffee ordered
The number of pounds may contain a decimal place
Each pound of coffee costs $13
When the user clicks the Calculate button, the button’s Click event procedure calculates and displays the total price of the order
Figure 11-2 Interface for the Coffee Palace–Version 1 application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

5. The Coffee Palace- Version 1 Application (Cont.)
Figure 11-3 Click procedure in the Coffee Palace–Version 1 application
Figure 11-6 Test data chart for the Coffee Palace–Version 1 application
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6. The Coffee Palace- Version 2 Application
Except for the title bar text, the interface is identical to the one in the Coffee Palace–Version 1 application
In this version of the application, the number of pounds entered in the Pounds ordered text box must be an integer
Each pound of coffee still costs $13
Figure 11-7 Interface for the Coffee Palace–Version 2 application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

7. The Coffee Palace- Version 2 Application (Cont.)
Figure 11-8 Click procedure in the Coffee Palace–Version 2 application
Figure 11-9 Test data chart for the Coffee Palace–Version 2 application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

8. The Coffee Palace- Version 2 Application (Cont.)
Figure Result of entering a non-integer in the text box
The TryParse method in the btnCalc_Click procedure cannot convert the non-integer 4.5 to the Integer data type, so it assigns the number 0 to the intPounds variable
When the intPounds variable contains the number 0, the total price will be 0
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9. The Coffee Palace- Version 2 Application (Cont.)
Stop! This Is a Restricted Area!
The application expects the user to enter the number of pounds as an integer (no letters, periods, or special characters)
Prevent the text box from accepting the character by coding the text box’s KeyPress event procedure
A control’s KeyPress event occurs each time the user presses a key while the control has the focus
Use the e parameter’s KeyChar property to determine the pressed key (KeyChar stands for “key character.”)
Use the e parameter’s Handled property to cancel the pressed key if it is an inappropriate one
Use the ControlChars.Back constant to refer to the Backspace key on a computer keyboard (necessary for editing the text box entry)
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

10. The Coffee Palace- Version 2 Application (Cont.)
Figure Examples of preventing a text box from accepting certain characters
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

11. The Shady Hollow Hotel Application
The interface for the Shady Hollow Hotel application displays the daily rate for a room at the hotel
The daily rate for a Standard room is $90
The daily rate for a Deluxe room is $115
The daily rate for a Suite is $130
Figure Interface for the Shady Hollow Hotel application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

12. The Shady Hollow Hotel Application (Cont.)
Figure btnGet_Click procedure in the Shady Hollow Hotel application
Figure Test data chart for the Shady Hollow Hotel application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

13. The CD Shop Application
The interface for the CD Shop application provides a text box for entering the number of CDs (compact discs) purchased
Each CD costs $10
The CD Shop offers the discounts
When the user clicks the Calculate button, the button’s Click event procedure calculates and displays the total due
Figure Interface for the CD Shop application
Figure CD Shop discounts
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

14. The CD Shop Application (Cont.)
Figure Test data chart for the CD Shop application
Figure btnCalc_Click and txtCds_KeyPress procedures
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

15. The Tiger Hotel Application
The Tiger Hotel application’s interface provides a text box for entering the room type
Standard Rooms cost $90
Deluxe Rooms cost $115
When the user clicks the Display Rate button, the button’s Click event procedure displays the daily rate in the Daily rate box
Figure Interface for the Tiger Hotel application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

16. The Tiger Hotel Application (Cont.)
Figure btnDisplay_Click procedure in the Tiger Hotel application
Figure Test data chart for the Tiger Hotel application
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17. The Tiger Hotel Application (Cont.)
I Need to Tell You Something
Create a message box using the MessageBox.Show method
Text in the titleBarText argument appears in the form’s title bar
The MessageBoxButtons.OK and MessageBoxIcon.Information arguments display an OK button and an Information icon
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

18. The Tiger Hotel Application (Cont.)
Figure Basic syntax and an example of the MessageBox.Show method
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

19. The Tiger Hotel Application (Cont.)
Figure Modified test data chart for the modified Tiger Hotel application
Figure Modified If…Then…Else statement
Figure Message Box
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20. The Tiger Hotel Application (Cont.)
Just When You Thought It Was Safe
No matter how thoroughly you test an application, it may still
contain some errors, called bugs
It’s almost impossible to create a set of test data that covers every possible scenario the application will encounter
The number of bugs is directly related to the size and complexity of the application
Figure Result of including a space after the room type
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21. The Tiger Hotel Application (Cont.)
Several ways to fix the bug in the application
Change the txtType control’s MaxLength property to 1 - this limits the text box entry to one character
Use the txtType control’s KeyPress event to prevent the text box from accepting the space character
Use the Trim method to remove any spaces that appear before and after the room type
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

22. The Tiger Hotel Application (Cont.)
Figure Basic syntax and examples of the Trim method
Figure Final test data chart for the Tiger Hotel application
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

23. The Tiger Hotel Application (Cont.)
Figure Final btnDisplay_Click procedure
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

24. Summary
Thoroughly test a program, using both valid and invalid data, before releasing the program to the user
Use a test data chart to record an application’s test data and the expected results
Prevent a text box from accepting a character by coding the text box’s KeyPress event procedure
Use the e parameter’s KeyChar property to determine the pressed key
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012

25. Summary (Cont.)
When there is a change to an application’s code, retest the application using the data listed in its test data chart
Use the MessageBox.Show method to display a message while an application is running
The Trim method makes a temporary copy of a string
It then performs the necessary trimming on the copy only
Clearly Visual Basic: Programming with Microsoft Visual Basic 2012