how did Malcolm test mac duff to check his loyalty?

Malcolm tests Macduff's loyalty with a series of questions. Malcolm, remembering his father's misplaced trust in Macbeth, decides to test Macduff: he confesses that he is a greedy, lustful, and sinful man who makes Macbeth look like an angel in comparison. Macduff despairs and says that he will leave Scotland forever if this is the case, since there seems to be no man fit to rule it. Upon hearing this, Malcolm is convinced of Macduff's goodness and reveals that he was merely testing him; he has none of these faults to which he has just confessed.