Test Class for the Apex Callout with OAuth

Question

I am trying to write the Test Class for the Apex Callout which uses the OAuth. The Apex Class with the future method is like below

@future (callout=true)
public static void createSegSubSegment(String jsonBody,String endPoint) {
    String clientId = '';
    String clientSecret = '';
    String resource = '';
    String tenant_id = '';
    String bearerToken = '';        
    try{                       
       ExtCred__c[] ExtCred_Data = [SELECT Client_ID__c,Client_Secret__c,Resource__c,Tenant_ID__c from ExtCred__c where Name = 'ThirdParty' ];
        if( ExtCred_Data.size() > 0 ) 
        {
            clientId = ExtCred_Data[0].Client_ID__c;
            clientSecret = ExtCred_Data[0].Client_Secret__c;
            resource = ExtCred_Data[0].Resource__c;
            tenant_id =  ExtCred_Data[0].Tenant_ID__c;

            String reqbody = 'grant_type=client_credentials&client_id='+clientId+'&client_secret='+clientSecret+'&tenant_id='+tenant_id+'&resource='+resource;

            Http h = new Http();
            HttpRequest req = new HttpRequest();
            req.setBody(reqbody);
            req.setMethod('POST');
            req.setEndpoint('https://login.microsoftonline.com/abc.org/oauth2/token');
            HttpResponse res = h.send(req);

            deserializeResponse resp1 = (deserializeResponse)JSON.deserialize(res.getbody(),deserializeResponse.class);
            bearerToken = resp1.access_token;

            Http http1 = new Http();
            HttpRequest req1 = new HttpRequest();
            String d365EndPoint = resource + endPoint;           
            req1.setMethod('POST');
            req1.setTimeout(20000);
            req1.setHeader('Authorization','Bearer '+bearerToken);
            req1.setEndpoint(d365EndPoint);
            req1.setBody(jsonBody);
            req1.setHeader('Content-Type', 'application/json;charset=UTF-8');
            HttpResponse res1 = http1.send(req1);

        }
    }

I tried to create a global test class which implements HttpCalloutMock like below

@isTest
global class HttpMockCalloutTest implements HttpCalloutMock{
    global HttpResponse respond(HTTPRequest req){
        HttpResponse res = new HttpResponse();
        res.setStatus('OK');
        res.setStatusCode(200);
        res.setBody('Test Mock Callout');
        return res;
    }
}

And the actual test class for the Apex Class like

private static testMethod void callFutureMethod() {      
     ID parentRecType = '012U0000000PqA9IAK';

    Account pa = new Account(Name='TestCallOut', recordTypeId=parentRecType,Data_Source_ID__c = 'TestPAX123');
    insert pa;

    Account acc = [Select id,Data_Source_ID__c from Account where Name like '%TestCallOut%'];

     SegJSON js = new SegJSON();
     js.dataAreaId = '123';
     js.SegmentCode = acc.Data_Source_ID__c ;
     String jsonBody = json.serialize(js); 
     String endPoint = '/data/parentAccounts'; 


    Test.startTest();
    Test.setMock(HttpCalloutMock.class, new HttpMockCalloutTest());
    handleD365Request.createSegSubSegment(jsonBody,endPoint);
    Test.stopTest();

}

    public class SegJSON {
    public String dataAreaId;
    public String SegmentCode;

    public SegJSON parse(String json) {
        return (SegJSON) System.JSON.deserialize(json, SegJSON.class);
    }
}

Even though when I run the test class it says successful but when I see the no code coverage. I see none of the line are covered starting from my if block if( ExtCred_Data.size() > 0 )

Answer 1

Mocks do not replace the need to create and insert appropriate test data to ensure your code executes the logic path you are aiming to test.

Here, your unit test code must create and insert a ExtCred__c record that meets the expectations of your code under test.

Additionally, you should use Schema methods like getRecordTypeInfosByDeveloperName() to dynamically access Record Type Ids, rather than hard-coding them.