Possible Clues:

• Deliberately test someone's patience
• Before buying a garment, you should see how far you can go
• Push one's luck
• Attempt to deceive
• Haberdasher's suggestion
• Unknown quantity in god so push your luck
• When buying new suit one should be bold
• "I wonder if this will fit" response
• Attempt to get away with something
• Hornblower holds back in convoy to attempt something audacious