t.throws(()=>m(newWeakMap([[{rainbow: true},'🌈']]),m.weakMap.label('foo').hasKeys({rainbow: true})),'Expected WeakMap `foo` to have keys `[{"rainbow":true}]`');
t.throws(()=>m(newWeakMap([[{rainbow: true},'🌈']]),m.weakMap.hasKeys({rainbow: true}).label('foo')),'Expected WeakMap `foo` to have keys `[{"rainbow":true}]`');
t.throws(()=>m(newWeakMap([[unicorn,'🦄'],[rainbow,'🌈']]),m.weakMap.hasKeys(unicorn,{rainbow: true})),'Expected WeakMap to have keys `[{"rainbow":true}]`');
t.throws(()=>m(newWeakMap([[keys[0],1],[keys[2],3]]),m.weakMap.hasKeys(...keys)),'Expected WeakMap to have keys `[{"x":2},{"x":4},{"x":5},{"x":6},{"x":7}]`');