Test Coverage issue for a simple rest-service class

Question

Just get started with Trailhead but got stuck with one challenge. It requires you to write an apex class to implement a REST GET service to retrieve an account and associated contacts. Then you have to write a test case to test. The issue is with test coverage. It always reports 83% code coverage. I am puzzled why it's not 100% as required. Which line of code is not covered by the test class?

Here is the getAccount service class

// accessible at /Accounts/<Account_ID>/contacts
@RestResource(urlMapping='/Accounts/*')
global with sharing class AccountManager {
    @HttpGet
    global static Account getAccount() {
        RestRequest request = RestContext.request;

        String str = request.requestURI.substring(0, request.requestURI.lastIndexOf('/'));
        String acctId = str.substring(str.lastIndexOf('/')+1);

        Account acct = [SELECT Id, Name, (SELECT Id, Name FROM Contacts) FROM Account WHERE Id = :acctId];
        return acct;
    }
}

And here is the test class:

@IsTest
public class AccountManagerTest {
    @isTest static void testGetAccount() {
        String id = '0018b00002VulQKAAZ';
        RestRequest request = new RestRequest();
        request.requestUri = 'https://my-dev-ed.trailblaze.my.salesforce.com/' + 
            'services/apexrest/Accounts/' + id + '/contacts';
        request.httpMethod = 'GET';
        RestContext.request = request;
        
        // call the method to test
        Account thisAcct = AccountManager.getAccount();
        
        // verify the results
        System.assert(thisAcct != null);
        System.assertEquals('Get Cloudy', thisAcct.Name);
    }
}

Any help would be greatly appreciated.

Answer 1

Because of Isolation of Test Data from Organization Data in Unit Tests, your test cannot access production data. For this reason, you should instead create any test data you need prior to using it.

Account testAccount = new Account(Name='Get Cloudy');
insert testAccount;
Id id = testAccount.Id;
// ... continue your test

Note that some objects are accessible, such as users, so please read the documentation above for exceptions to this rule.

The reason you had 83% coverage is because the line that queries the account record has no rows returned because of database isolation, so the test would fail with:

System.QueryException: List has no rows for assignment to SObject

The last line, return acct would be the line that was uncovered.