Learn VB Script - Part 4

Operators

Operators precedence

When several operations occur in an expression, each part is evaluated and resolved in a predetermined order called operator precedence. You can use parentheses to override the order of precedence and force some parts of an expression to be evaluated before others. Operations within parentheses are always performed before those outside. Within parentheses, however, standard operator precedence is maintained.


When expressions contain operators from more than one category, arithmetic operators are evaluated first, comparison operators are evaluated next, and logical operators are evaluated last. Comparison operators all have equal precedence; that is, they are evaluated in the left-to-right order in which they appear. Arithmetic and logical operators are evaluated in the following order of precedence.

Arithmetic		Comparison		Logical
Description	Symbol	Description	Symbol	Description	Symbol
Exponentiation	^	Equality	=	Logical negation	Not
Unary negation	-	Inequality	<>	Logical conjunction	And
Multiplication	*	Less than	<	Logical disjunction	Or
Division	/	Greater than	>	Logical exclusion	Xor
Integer division	\	Less than or equal to	<=	Logical equivalence	Eqv
Modulus arithmetic	Mod	Greater than or equal to	>=	Logical implication	Imp
Addition	+	Object equivalence	Is
Subtraction	-
String concatenation	&

Learn VB Script Part 3

Data Types

What Are VBScript Data Types?

VBScript has only one data type called a Variant. A Variant is a special kind of data type that can contain different kinds of information, depending on how it's used. Because Variant is the only data type in VBScript, it's also the data type returned by all functions in VBScript.

At its simplest, a Variant can contain either numeric or string information.

       A Variant behaves as a number when you use it in a numeric context and as a string when you use it in a string context. That is, if you are working with data that looks like numbers, VBScript assumes that it is numbers and does what is most appropriate for numbers. Similarly, if you're working with data that can only be string data, VBScript treats it as string data. You can always make numbers behave as strings by enclosing them in quotation marks (" ").

Variant Subtypes

Beyond the simple numeric or string classifications, a Variant can make further distinctions about the specific nature of numeric information. For example, you can have numeric information that represents a date or a time. When used with other date or time data, the result is always expressed as a date or a time.

You can also have a rich variety of numeric information ranging in size from Boolean values to huge floating-point numbers. These different categories of information that can be contained in a Variant are called subtypes. Most of the time, you can just put the kind of data you want in a Variant, and the Variant behaves in a way that is most appropriate for the data it contains.

The following table shows subtypes of data that a Variant can contain. 

Subtype	Description
Boolean	Logical value: true (numeric value is "nonzero", mostly -1) or false (numeric value is 0) See the notes below.
Byte	Integer value (1 byte) in the range: 0 to 255.
Integer	Integer value (2 bytes) in the range: -32,768 to 32,767.
Long	Integer value (4 bytes) in the range: -2,147,483,648 to 2,147,483,647.
Single	Real value (4 bytes) with the precision 7 digits in the range: -3.402823E38 to -1.401298E-45 for negative values. 1.401298E-45 to 3.402823E38 for positive values. Binary implementation format is according to standard IEEE-754 (32-bit)
Double	Real value (8 bytes) with the precision 15 digits in the range: -1.79769313486232E308 to -4.94065645841247E-324 for negative values. 4.94065645841247E-324 to 1.79769313486232E308 for positive values. Binary implementation format is according to standard IEEE-754 (64-bit)
Date	Value containing Date and time. See the notes below.
String	variable-length string that can be up to approximately 2 billion characters in length in the Unicode character set.
Object	"pointer" (reference) to any object.
Array	Array of values. See How to use array of values in the PROMOTIC system.
Empty	Flag that value is uninitialized.
Null	Flag that value intentionally contains no valid data.

Numeric data types Byte, Integer and Long:

Entering the values with hexadecimal constant:

It is possible to enter a number into the variable in decimal figure, for example:
nVal = 36524

or in hexadecimal figure, where the &h prefix is used, for example:
nVal = &h8EAC


(8EAC hexadecimly is 36524 decimaly). But the VBScript evaluates the hexadecimal constants the following way: if the constant is two byte (like we have here), then it creates Integer data type. Because the value 8EAC has the highest bit set, then the constant will be considered as negative numberequal to -29012!

Boolean data type:

Value of the Boolean type can logicaly have just two states (true / false), but it is actually stored asInteger data type and it is supposed that false is zero and true is non-zero.

And this way of understanding the true value can cause trouble, because by default the value is -1, but also any other non-zero value is also true !! That is why we do not recommend comparing the truevalues.

Example:

If value = true Then ...

Date data type:

If the value of the date/time is stored as Date data type, then the values of year/month/day/hour/minute/second can be obtained, for example, by the VBScript methods Year/Month/Day/Hour/Minute/Second. See also VBScript date and time functions and Pm date and time methods.

Date creating from String data type:

The required date (time, date and time) must be written into quotation marks in the format specified in Windows settings "Control Panel / Date/Time / Date and time page". For example, if the date is set in the format d.M.yyyy in the local setting, then the time can be entered as String in the following way:

Dim MyTime, MyDate, MyDateTime

MyTime = CDate("18:59:33")

MyDate = CDate("31.12.2015")

MyDateTime = CDate("31.12.2015 18:59:33")

Date creating by the VBScript constant:

If the date (time, date and time) is entered by this way, it doesn't depend on setting the computer and the date (time, date and time) will always be in the correct format. The date (time, date and time) is entered by the # char in the format #dd/mm/yy# (or #hh:mm:ss# or #dd/mm/yy hh:mm:ss#):

Dim MyTime, MyDate, MyDateTime

MyTime = #18:59:33#

MyDate = #23/10/05#

MyDateTime = #23/10/13 18:59:33#

Date creating from real number:

The date (year, month, day) is represented by the whole part of the real number.

It is a number of days since 30.12.1899. Value 1.0 refers to the date 31.12.1899, value –1.0 refers to the date 29.12.1899.

The time (hours, minutes, seconds) is represented by the decimal part of the real number. The value x.5 means the exact midday (12:00:00) in the day x.

The value from 0.0 to 1.0 is a special case. The value is not considered to be a date but only as time or time range. The value 0.5 represents 12 hours, 1/24/60 represents 1 minute.

The following script assigns the value of the date and the time greater by one day and by one minute into the variable MyDateTime on each execution of the script.

MyDateTime = CDate(MyDateTime + 1 + 1/24/60)

If the variable MyDateTime is initialized by value 1, then after the first execution of the script, the value of the variable equals to "1.1.1900 0:01:00", after the second execution, it equals to "2.1.1900 0:02:00".

Learn VB Script Part 2

Variables


What is a variable?

A variable is a convenient placeholder that refers to a computer memory location where you can store program information that may change during the time your script is running. 


Declaring a Variable

Declare variables explicitly in your script using the Dim statement, the Public statement, and the Private statement.

Examples:

Dim length
Dim height

Declare multiple variables by separating each variable name with a comma

Dim radius,area,side


Option Explicit 

We can also declare a variable implicitly by simply using its name in your script. That's not generally a good practice because you could misspell the variable name in one or more places, causing unexpected results when your script is run. For that reason, the Option Explicit statement is available to require explicit declaration of all variables. The Option Explicit statement should be the first statement in your script.




Rules for variable declaration

Variable names follow the standard rules for naming anything in VBScript.
A variable name:

• Must begin with an alphabetic character.
• Cannot contain an embedded period.
• Must not exceed 255 characters.
• Must be unique in the scope in which it is declared.

Assign values to variables

The variable is on the left side of the expression and the value you want to assign to the variable is on the right

Example

height = 10
length = 20

Learn VB Script Part 1

My First program in VB Script

To run scripts using the Windows-based script host (Wscript.exe) Browse to the folder containing the script you want to run and double-click it. 

From a command prompt window

At the command prompt, type the name of the Windows Host executable file (Wscript.exe), followed by a space, then the full path name of the script you want to run. Be sure to include the file name extension of the script file. Press Enter to start the script.

Note

• Windows scripts are files with the following file name extensions: .wsf, .vbs, .js.

• If you double-click a script file whose extension has not been associated with Wscript.exe, the Open With dialog box appears. Select Wscript.exe, then select Always use this program to open this file type. This registers Wscript.exe as the default script host for files of this file type.

• You can use the Windows Script Host Settings dialog box to set global scripting properties for all scripts that Wscript.exe runs on the local computer 

• You can set properties for individual scripts. See Related Topics for information about how to do this.

• You can also use Windows Script Host to create .wsf script files, with which you can call multiple scripting engines and perform multiple jobs, all from one file.

Sample programs: 

Copy paste the below code in a note pad and save the files as .vbs in any directory of your personal computer and run the file as above.

Program 1:

'****HelloWorld******

MsgBox "Hello World !!!"

Program 2:

'**** Addition of two numbers***

Dim a,b

a = 1

b = 2

Msgbox "Addition of two number is "&a+b

Some more programs and full description of each program follows in next post

What is VB script?

VBScript ("Visual Basic Scripting Edition") is an Active Scripting language developed by Microsoft that is modeled on Visual Basic. It is designed as a "lightweight" language with a fast interpreter for use in a wide variety of Microsoft environments.

Microsoft Visual Basic Scripting Edition, the newest member of the Visual Basic family of programming languages, brings active scripting to a wide variety of environments, including Web client scripting in Microsoft Internet Explorer and Web server scripting in Microsoft Internet Information Server.

Easy to Use and Learn

If you already know Visual Basic or Visual Basic for Applications, VBScript will be very familiar. Even if you don't know Visual Basic, once you learn VBScript, you're on your way to programming with the whole family of Visual Basic languages. Although you can learn about VBScript in just these few Web pages, they don't teach you how to program. To get started programming, take a look at Step by Step books available from Microsoft Press.

ActiveX Scripting

VBScript talks to host applications using ActiveX™ Scripting. With ActiveX Scripting, browsers and other host applications don't require special integration code for each scripting component. ActiveX Scripting enables a host to compile scripts, obtain and call entry points, and manage the namespace available to the developer. With ActiveX Scripting, language vendors can create standard language run times for scripting. Microsoft will provide run-time support for VBScript. Microsoft is working with various Internet groups to define the ActiveX Scripting standard so that scripting engines can be interchangeable. ActiveX Scripting is used in Microsoft® Internet Explorer and in Microsoft® Internet Information Server.

VBScript in Other Applications and Browsers

As a developer, you can license VBScript source implementation at no charge for use in your products. Microsoft provides binary implementations of VBScript for the 32-bit Windows® API, the 16-bit Windows API, and the Macintosh®. VBScript is integrated with World Wide Web browsers. VBScript and ActiveX Scripting can also be used as a general scripting language in other applications.

Microsoft Visual Basic Scripting Edition, the newest member of the Visual Basic family of programming languages, brings active scripting to a wide variety of environments, including Web client scripting in Microsoft Internet Explorer and Web server scripting in Microsoft Internet Information Server.

What is Automation Testing ?

Manual testing is performed by a human sitting in front of a computer carefully executing the test steps. Automation Testing means using an automation tool to execute your test case suite.   The automation software can also enter test data into the System Under Test ,  compare  expected and actual  results and generate detailed test  reports.

Test Automation demands considerable investments of money and resources. Successive development cycles will require execution of same test suite repeatedly. Using a test automation tool it's possible to record this test suite  and re-play it  as required. Once the  test suite is automated,  no human intervention is required . This improved ROI of Test Automation.

Goal of Automation is to reduce number of test cases to be run manually and not eliminate manual testing all together.

Why Automated Testing?

Automated testing is important due to following reasons: 

• Manual Testing of all work flows, all fields , all negative scenarios is time and cost consuming
• It is difficult to test for multi lingual sites manually
• Automation does not require Human intervention. You can run automated test unattended (overnight)
• Automation increases  speed of test execution
• Automation helps increase  Test Coverage
• Manual Testing can become boring and hence error prone.

 

Which Test Cases to Automate?

Test cases to be automated can be selected using the following criterion to increase the automation ROI

• High Risk - Business Critical test cases
• Test cases that are executed repeatedly
• Test Cases that are very tedious or difficult to perform manually
• Test Cases which are time consuming

The following category of test cases are not suitable for automation:

• Test Cases that are newly designed and not executed manually  atleast once
• Test Cases for which the requirements are changing frequently
• Test cases which are executed on ad-hoc basis.

Automation Process

Test tool selection

Test Tool selection largely depends on the technology the Application Under Test is built on. For instance QTP does not support Informatica.  So QTP cannot be used for testing Informatica applications. It's a good idea to conduct Proof of Concept of Tool on AUT

Define the scope of Automation

Scope of automation is the area of your Application Under Test which will be automated. Following points help determine scope:

• Feature that are important for the business
• Scenarios which have large amount of data
• Common functionalities across applications
• Technical feasibility
• Extent to which business components are reused
• Complexity of test cases
• Ability to use the same test cases for cross browser testing

Planning, Design and Development 

During this phase you create  Automation strategy & plan, which contains following details-

• Automation tools selected
• Framework design and its features
• In-Scope and Out-of-scope items of automation
• Automation test bed preparation
• Schedule and Timeline of scripting and execution
• Deliverables of automation testing

Test Execution

Automation Scripts are executed during this phase. The scripts need input test data before there are set to run. Once executed they provide detailed test reports.  

Execution can be performed using the automation tool directly or through the Test Management tool which will invoke the automation tool.

Example: Quality center is the Test Management tool which in turn it will invoke QTP for execution of automation scripts. Scripts can be executed in a single machine or a group of  machines. The execution can be done during night , to save time.

Maintenance

 As new functionalities are added to the System Under Test with successive cycles, Automation Scripts need to be added, reviewed and maintained for each release cycle. Maintenance becomes necessary to improve effectiveness of Automation Scripts. 

Referances