@isTest
public class YourTestClassName {
    static testMethod void testYourCode() {
		// Create test Opportunity for PROJECT_STAGE_PENDING_APPROVAL 
        Opportunity testOpportunityPENDING = new Opportunity(
            Name = 'Test Opportunity',
            StageName = PROJECT_STAGE_PENDING_APPROVAL , 
            RecordTypeId = 'YourRecordTypeId' // Set the appropriate Record Type Id for setRecTypeID.contains(opp.RecordTypeID)
            // Add other required fields
        );
        insert testOpportunityPENDING;
		
        // Create test Opportunity for PROJECT_STAGE_APPROVED_FOR_PAYMENT
        Opportunity testOpportunityAPPROVED = new Opportunity(
            Name = 'Test Opportunity',
            StageName = PROJECT_STAGE_APPROVED_FOR_PAYMENT, 
            RecordTypeId = 'YourRecordTypeId' // Set the appropriate Record Type Id for setRecTypeID.contains(opp.RecordTypeID)
            // Add other required fields
        );
        insert testOpportunityAPPROVED;

        // Create OpportunityLineItem
        OpportunityLineItem testOpportunityLineItem = new OpportunityLineItem(
            OpportunityId = testOpportunityAPPROVED.Id,
            ESA_Total_Approved_Cost_EI__c = 1000.00, // Set your desired values for these fields
            Payment_EI__c = null, // Set Payment_EI__c as needed
            // Add values for other fields as required
        );
        insert testOpportunityLineItem;

        // Call the method you want to test
        Test.startTest();
        YourClass.yourMethod(); // Replace YourClass and yourMethod with actual class and method names
        Test.stopTest();

        // Assert the expected results
        // You may need to query the data to verify the results as needed
        // Example:
        List<OpportunityLineItem> oppLineItems = [SELECT Id FROM OpportunityLineItem WHERE OpportunityId = :testOpportunity.Id];
        System.assertEquals(1, oppLineItems.size(), 'Expected OpportunityLineItem to be created.');

        // Add more assertions as needed
    }
}