Create TestCases

[marlonjsilva]

Create testcases for the following classes:

• Customer;
• Accounts;
• Payments;
• Installments;
• Subscriptions;
• PaymentLinks;
• Transfers;
• Antecipations;
• PaymentDunnings;
• Bill;
• CreditBureauReports;
• FinancialTransactions;
• MyAccount;
• Invoices;
• CustomerFiscalInfo;
• MobilePhoneRecharge;
• Webhooks;