This happened in Wilson v Wilson, where Federal Magistrate Lapthorn was confronted with that rare creature- the contested divorce.
The issue that his Honour had to tackle was the date of separation. If it were the husband's, then there was 12 months of separation. if the wife's there was less than 12 months. Ultimately his Honour found that the husband had not established the 12 months, and dismissed the application.
His Honour set out the test for separation under the one roof:
When parties have separated under the one roof it is often difficult to determine at what particular point they separated especially if they have been experiencing marital difficulties for a lengthy period of time. In many instances married couples will have had discussions about separating but take some time before they actually arrive at the point of separation. Indeed in the course of those discussions a party may even say the marriage is over but not act on that statement for some time. For there to be a separation there needs to be not only the communication of the fact from one party to the other but also some action to confirm that intention. In cases where a party moves out of the matrimonial home it may be said that that move is both communicated and acted upon depending on the circumstances. When the parties remain under the one roof however the court would need to be satisfied that there has been an intention to separate by at least one person followed by a communication of that intention with some form of action following the communication to confirm the intention. Federal Magistrate Maguire in Aitken & Deakin held the view that the communication needed to be unambiguous and unconditional. Her Honour considered the test of the element of communication to be an objective one. With respect I agree. (emphasis added)