javascript - ChaiJS expect constructor to throw error -

i trying test constructor throw error using teaspoon gem rails, chaijs assertion library.

when run following test:

  it('does not create seat if x < 0', function() {     var badconstructor = function() {       return new seat({ radius: 10, x: -0.1, y: 0.2, seat_number: 20, table_number: 30});     };      expect(badconstructor).to.throw(error, 'invalid location');   }); 

i output:

failures:

  1) seat not create seat if x < 0      failure/error: undefined not constructor (evaluating 'expect(badconstructor).to.throw(error(), 'invalid location')') 

the constructor throwing error, think not writing test properly.

when try running expect(badconstructor()) output:

failures:    1) seat not create seat if x < 0      failure/error: invalid location 

had same problem. wrap constructor function:

var fcn = function(){new badconstructor()}; expect(fcn).to.throw(error, 'invalid location');