Add better diffing for calledWith and calledWithExactly failures

[bskiff]

Currently when a test fails it provides output the following way:
e.g.

const fooObject = {
    foo: 'foo'
};
const barObject = {
    bar: 'bar'
};
const stub = sinon.stub();

stub(fooObject);

expect(stub).to.be.calledWithExactly(barObject);

prints

AssertionError: expected stub to have been called with exact arguments { bar: "bar" }
{ foo: "foo" } { bar: "bar" }

It would be nice if this was a proper diff similar to what Chai's deep equal assertions provide.
e.g.

const fooObject = {
    foo: 'foo'
};
const barObject = {
    bar: 'bar'
};

expect(fooObject).to.deep.equal(barObject);

prints

 AssertionError: expected { foo: 'foo' } to deeply equal { bar: 'bar' }                        
 + expected - actual                                                                           
                                                                                               
  {                                                                                            
 -  "foo": "foo"                                                                               
 +  "bar": "bar"                                                                               
  }                                                                                             

Editors such as IntelliJ IDEA have support for the latter style and will provide a nicely formatted diff in their diffing tools if that convention is followed.

[troynguyen8]

Any status on this? My team is facing this issue. Using calledWithExactly is much cleaner than expect(spy.lastCall.args).to.equal(expectedCall)

[domenic]

https://mobile.twitter.com/slicknet/status/782274190451671040

[kuceb]

I've got a PR open here #141

[AdRaslan]

I had the same problem and it was solved by using JSON.stringify(). Try this:

const fooObject = {
foo: 'foo'
};
const barObject = {
bar: 'bar'
};
const stub = sinon.stub();

stub(fooObject);

expect(stub).to.be.calledWithExactly(JSON.stringify(barObject));

[benjick]

Any news on this?

[alannaidon]

Any news? 👀

[eliasm307]

Any news on this?