Class Apex触发器测试课程-初学者指南

我对编码相对缺乏经验，以前从未被迫编写测试类。我在概念上不理解它。我编写了以下触发器：

trigger CreateNewInvoiceAndUpdateCM on CampaignMember(after insert, after update){
for (CampaignMember cm: trigger.new){

    if(cm.Status == 'Needs Renewal and Invoice'){
        Asset memb = [SELECT Id, Product2Id FROM Asset WHERE Id = :cm.Membership__c];
        Product2 prod = [SELECT Id, ProductCode FROM Product2 WHERE Id = :memb.Product2Id];
        Pricebook2 pb =[SELECT Id, Name FROM Pricebook2 WHERE Name = 'Standard Price Book'];
        PricebookEntry pbe = [SELECT Id, UnitPrice, Pricebook2Id, Product2Id FROM PricebookEntry WHERE Pricebook2Id = :pb.Id AND Product2Id = :prod.Id];

        Invoice__c inv = new Invoice__c();
        inv.Membership__c = cm.Membership__c;
        inv.Contact__c = cm.ContactId;
        inv.Price__c = pbe.UnitPrice;
        insert inv;



        CampaignMember newCm = [select Id, Invoice__c FROM CampaignMember WHERE Id = :cm.Id];
        newCm.Invoice__c = inv.Id;
        newCM.Status = 'Needs Renewal';
        update newCm;

        }}
        }

但是我不知道如何正确地编写测试类。我已经浏览了Salesforce网站上的所有文档和这里的无数帖子，但是我没有将代码覆盖率从13%（2/15）[顺便说一句，这意味着什么？]提高到13%

我编写的测试类基本上只是尝试将所有内容都放在其中，希望代码覆盖率能够提高。我不知道我在测试课上应该做什么：

@isTest 

private class testCreateNewInvoiceAndUpdateCM{

static testMethod void testCreateNewInvoiceAndUpdateCM(){

PricebookEntry pbe = new PriceBookEntry();
pbe.UnitPrice = 2;

Campaign camp = new Campaign();
camp.Name = 'Test Campaign';
insert camp;

Account acc = new Account();
acc.Name ='Test Account';
insert acc;

Contact cont= new Contact();
cont.LastName = 'LastName';
cont.AccountId = acc.Id;
insert cont;


Asset ass = new Asset();
ass.Name = 'Test Asset';
ass.Membership_Start_Date__c = System.today();
ass.ContactId = cont.Id;
ass.AccountId = ass.Id;
insert ass;

Invoice__c inv = new Invoice__c();
inv.Membership__c = ass.Id;
inv.Contact__c = cont.Id;
inv.Price__c = pbe.UnitPrice;
insert inv;

CampaignMember cm = new CampaignMember(); 
cm.CampaignId = camp.Id;
cm.ContactId = cont.Id;
cm.Membership__c = ass.Id;
cm.Status = 'Needs Renewal and Invoice';
cm.Invoice__c = Inv.Id;

insert cm;


CampaignMember cm2 = [select Id, Status, Invoice__c  from CampaignMember where Id = :cm.Id];
System.assertEquals('Needs Renewal and Invoice',cm.Status);







   }
}

有人能帮我一下吗？这让我发疯了。

（2/15）意味着（触发器的）15行中有2行通过了测试，你还有13行要测试，这意味着你的测试类代码没有覆盖这13行。

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您能指定触发器的哪两行通过了测试吗？这肯定有助于理解问题的症结所在。

在编写测试类之前，您需要重写触发器。您从不在for循环内部查询。您还应该通过使用联接来最小化查询的数量。您应该查看apex最佳实践指南。从这里开始：