Quality Assurance and Testing with Chai - expected 'failed' to equal 'passed'

I really dont know why I am getting this error on my Quality Assurance and Testing with Chai challenges…

 expected 'failed' to equal 'passed'

my code so far:

var chai = require('chai');
var assert = chai.assert;

suite('Unit Tests', function(){
  
  // Make ALL tests pass
  // !! Don't scramble the Assertions. We rely on their order to check the results !!
  suite('Basic Assertions', function() {
    /** assert.fail() will always fail. Change it into something more useful... **/
  
    /** 1 - Use assert.isNull() or assert.isNotNull() to make the tests pass. **/
    test('#isNull, #isNotNull', function(){
      assert.isNull(null, 'this is an optional error description - e.g. null is null');
      assert.isNotNull( 1, '1 is not null');
    });
  
    /** 2 - Use assert.isDefined() or assert.isUndefined() to make the tests pass. **/
    test('#isDefined, #isUndefined', function(){
      assert.isDefined()( null, 'null is not undefined');
      assert.isUndefined()( undefined, 'undefined IS undefined');
      assert.isDefined()( 'hello', 'a string is not undefined' );
    });
  

image

Does anyone know what’s going on?
Challenge:
https://learn.freecodecamp.org/information-security-and-quality-assurance/quality-assurance-and-testing-with-chai/test-if-a-variable-or-function-is-defined

You have too many parentheses in your assertions.

assert.isDefined()( null, 'null is not undefined');
vs
assert.isDefined( null, 'null is not undefined');

That is sooooo stupid :sob:
You saved my day! Thank you @lasjorg