Mocking

Mocking provides a way to substitute records from a Database with some prepared data. Data can be prepared in form of SObject records and lists in Apex code or Static Resource .csv file. Mocked queries won't make any SOQL's and simply return data set in method definition, mock will ignore all filters and relations, what is returned depends solely on data provided to the method. Mocking is working only during test execution. To mock SOQL query, use .mockId(id) method to make it identifiable. If you mark more than one query with the same ID, all marked queries will return the same data.

public with sharing class ExampleController {

    public static List<Account> getPartnerAccounts(String accountName) {
        return SOQL_Account.query()
            .with(Account.BillingCity, Account.BillingCountry)
            .whereAre(SOQL.FilterGroup
                .add(SOQL.Filter.name().contains(accountName))
                .add(SOQL.Filter.recordType().equal('Partner'))
            )
            .mockId('ExampleController.getPartnerAccounts')
            .toList();
    }
}

Then in test simply pass data you want to get from Selector to SOQL.setMock(id, data) method. Acceptable formats are: List<SObject> or SObject. Then during execution Selector will return desired data.

List of records

@IsTest
private class ExampleControllerTest {

    @IsTest
    static void getPartnerAccounts() {
        List<Account> accounts = new List<Account>{
            new Account(Name = 'MyAccount 1'),
            new Account(Name = 'MyAccount 2')
        };

        SOQL.setMock('ExampleController.getPartnerAccounts', accounts);

        // Test
        List<Account> result = ExampleController.getPartnerAccounts('MyAccount');

        Assert.areEqual(accounts, result);
    }
}

Single record

@IsTest
private class ExampleControllerTest {

    @IsTest
    static void getPartnerAccount() {
        SOQL.setMock('ExampleController.getPartnerAccount', new Account(Name = 'MyAccount 1'));

        // Test
        Account result = (Account) ExampleController.getPartnerAccounts('MyAccount');

        Assert.areEqual('MyAccount 1', result.Name);
    }
}

Static resource

@IsTest
private class ExampleControllerTest {

    @IsTest
    static void getPartnerAccounts() {
        SOQL.setMock('ExampleController.getPartnerAccounts', Test.loadData(Account.SObjectType, 'ProjectAccounts'));

        // Test
        List<Account> result = ExampleController.getPartnerAccounts('MyAccount');

        Assert.areEqual(5, result.size());
    }
}

Count Result

@IsTest
private class ExampleControllerTest {

    @IsTest
    static void getPartnerAccountsCount() {
        SOQL.setCountMock('mockingQuery', 2);

        Integer result = SOQL.of(Account.sObjectType).count().mockId('mockingQuery').toInteger();

        Assert.areEqual(2, result);
    }
}

Sub-Query

To mock a sub-query we need to use deserialization mechanism. There are two approaches, using JSON string or Serialization/Deserialization. Then after deserialization to desired SObjectType, pass the data to SOQL by calling .setMock method.

Using JSON String

By passing simple String, it is possible to write non-writable fields, like Name on Contact object.

@IsTest
static void getAccountsWithContacts() {
    List<Account> mocks = (List<Account>) JSON.deserialize(
        '[{ "Name": "Account Name", "Contacts": { "totalSize": 1, "done": true, "records": [{ "Name": "Contact Name", "Email": "contact.email@address.com" }] }  }],
        List<Account>.class
    );

    List<Account> accounts;

    Test.startTest();
    SOQL.setMock('AccountsController.getAccountsWithContacts', mocks);
    accounts = AccountsController.getAccountsWithContacts();
    Test.stopTest();

    Assert.isNotNull(accounts);
    Assert.isNotNull(accounts[0].contacts);
    Assert.areEqual(1, accounts[0].contacts.size());
}

Using Serialization/Deserialization

Using this approach it is possible to bind data with additional logic, like using Test Data Factory.

@IsTest
static void getAccountsWithContacts() {
    List<Account> mocks = (List<Account>) JSON.deserialize(
        JSON.serialize(
            new List<Map<String, Object>>{
                new Map<String, Object>{
                    'Name' => 'Account Name',
                    'Contacts' => new Map<String, Object>{
                        'totalSize' => 1,
                        'done' => true,
                        'records' => new List<Contact>{ new Contact(FirstName = 'Contact', LastName = 'Name', Email = 'contact.email@address.com') }
                    }
                }
            }
        ),
        List<Account>.class
    );

    List<Account> accounts;

    Test.startTest();
    SOQL.setMock('AccountsController.getAccountsWithContacts', mocks);
    accounts = AccountsController.getAccountsWithContacts();
    Test.stopTest();

    Assert.isNotNull(accounts);
    Assert.isNotNull(accounts[0].contacts);
    Assert.areEqual(1, accounts[0].contacts.size());
}