thenThrow does not work if stub passed down

[gotenxds]

Hi, for some reason (context?) when using thenThrow, the method wont throw if it is being passed to another method

Example:

let someObjtWithThrowMethod = td.object(originalObj);
when(someObjtWithThrowMethod.throw(anything()).thenThrow(new Error('HO GOD NO');

//....

it('w/e', () => {
   someMethod(someObjtWithThrowMethod.throw) // This method calles the given method.

   verify(someObjtWithThrowMethod.throw(anything)) // true! but no exception is thrown!
}


it('w/e2', () => {
   someObjtWithThrowMethod.throw() // throws!
}

[searls]

Can you please provide a reproducible example? This doesn't seem right and the example isn't enough to debug with

[gotenxds]

running on mac node 8-lts

const td = require('testdouble');

describe.only('', () => {
  function funcCaller(func) {func()}
  
  const obj = td.object({throw: () => {}});
  it('Shold throw error', () => {
    td.when(obj.throw()).thenThrow(new Error('HAAAAA'));
    
    try {
      obj.throw();
    }
    catch(e) {
      console.log('YAY'); // works as expected
    }
  });

  it('Shold throw error2', () => {
    td.when(obj.throw()).thenThrow(new Error('HAAAAA'));
    
    try {
      funcCaller(obj.throw);
    }
    catch(e) {
      console.log('YAY'); // never gets here
    }
  });
});

[searls]

In test runners like mocha & jasmine, it's unsafe to execute any per-test code inside of a describe callback. The describe callback is invoked before any tests in the entire suite run (tools invoke these immediately to build out the tree/structure/plan of what will be tested), whereas before and it callbacks are called on a per-test basis and can be regarded as "test-time execution".

As a result, you should definitely have the td.object() assignment inside of the test itself, whether in a before hook or the it. What you have currently will invoke before any tests in any other file, and anything one test does with it will impact the other test. In addition, anyone that calls td.reset() (which should be set in a global after hook) could influence its state and affect whether your test works, which you don't want.

Changed example:

describe.only('', () => {
  function funcCaller(func) {func()}
  
  it('Shold throw error', () => {
    const obj = td.object({throw: () => {}});

    td.when(obj.throw()).thenThrow(new Error('HAAAAA'));
    
    try {
      obj.throw();
    }
    catch(e) {
      console.log('YAY'); // works as expected
    }
  });

  it('Shold throw error2', () => {
    const obj = td.object({throw: () => {}});

    td.when(obj.throw()).thenThrow(new Error('HAAAAA'));
    
    try {
      funcCaller(obj.throw);
    }
    catch(e) {
      console.log('YAY'); // never gets here
    }
  });
});