Custom Salesforce Button to Execute JavaScript

1. From Setup in your DE org, click Create | Objects and Select any one on which you wants custom button.
2. Scroll down to the Buttons, Links, and Actions section and click New Button or Link.
3. In the Label field, enter "label name".
4. For Display Type choose Detail Page Button.
5. For Behavior choose Execute JavaScript.
6. For Content Source choose OnClick JavaScript.

Notice that you are creating a Detail Page button that executes some JavaScript. For your convenience, here is the JavaScript example code that you can copy and paste into the form: 

  

{!REQUIRESCRIPT("/soap/ajax/30.0/connection.js")}

{!REQUIRESCRIPT("/soap/ajax/30.0/apex.js")}

sforce.connection.sessionId = '{!$Api.Session_ID}';     

var result = sforce.connection.describeSObject("Contact");

for (var i=0; i<result.fields.length; i++) { 

var field = result.fields[i];

alert(field.name);

}

Set Up Test Data in Salesforce Test Class

Set Up Test Data for an Entire Test Class

Use test setup methods (methods that are annotated with @testSetup) to create test records once and then access them in any test method in the test class. Test setup methods are useful and can be time-saving when you need to create a common set of records that all test methods operate on or prerequisite data.

Records created in a test setup method are rolled back at the end of test class execution. Test setup methods enable you to create common test data easily and efficiently. By setting up records once for the class, you don’t need to re-create records for each test method.

Syntax:

Test setup methods are defined in a test class, take no arguments, and return no value. The following is the syntax of a test setup method.

@testSetup static void methodName() {

}

Example:

@isTest
public class TestSetupMethodCls{
 
    @testSetup static void TestSetupMethod(){
Account acc = new Account(Name = 'Test Acc');
                insert acc;
}

static testMethod void TestAccount(){
Account acc = [Select Id, Name form Account Limit 1];
System.assertEquals('Test Acc', acc.Name);
}

}

Test Setup Method Considerations:

Test setup methods are supported only with the default data isolation mode for a test class. If the test class or a test method has access to organization data by using the @isTest(SeeAllData=true) annotation, test setup methods aren’t supported in this class.

 Multiple test setup methods are allowed in a test class, but the order in which they’re executed by the testing framework isn’t guaranteed.

• If a fatal error occurs during the execution of a test setup method, such as an exception that’s caused by a DML operation or an assertion failure, the entire test class fails, and no further test methods are executed.
• If a test setup method calls a non-test method of another class, no code coverage is calculated for the non-test method.