What is the test for enforcing a creditor’s obligation to pay a debt in lieu of payment of the debt?

There are numerous authorities which support this dictum, and it is unnecessary for me to quote them, as the principle has been established for many years, and is not now open to question. I may, however, refer to one which was quoted by learned counsel for the defence, and which seems to epitomize the law upon this subject very clearly: Sayer v. Wogstaff (1844) 5 Beav. 415, at 423, 49 E.R. 639, where the following dictum occurs: “The debt may be considered as actually paid, if the creditor, at the time of receiving the note, has agreed to take it in payment of the debt, and to take upon himself the risk of the note being paid, or if, from the conduct of the creditor or the special circumstances of the case, such an agreement is legally to be implied. “But in the absence of any special circumstances throwing the risk of the note upon the creditor, his receiving the note in lieu of present payment of the debt is no more than giving extended credit, postponing the demand for immediate payment, or giving time for payment on a future day, in consideration of receiving this species of security. Whilst the time runs, payment cannot legally be enforced, but the debt continues till payment is actually made; and if payment be not made when the time has run out, payment of the debt may be enforced as if the note had not been given.”