== Why is this an issue?

Many assertions compare two objects or properties of these objects. Passing twice the same argument is likely to be a bug due to developer's carelessness.


This rule raises an issue when a Chai assertion is given twice the same argument.

=== Noncompliant code example

[source,javascript]
----
const assert = require('chai').assert;

describe("test the same object", function() {
    it("uses chai 'assert'", function() {
        const expected = '1'
        const actual = (1).toString()
        assert.equal(actual, actual);  // Noncompliant
    });
});
----

=== Compliant solution

[source,javascript]
----
const assert = require('chai').assert;

describe("test the same object", function() {
    it("uses chai 'assert'", function() {
        const expected = '1'
        const actual = (1).toString()
        assert.equal(actual, expected);
    });
});
----

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Replace this argument or its duplicate at position [X].


=== Highlighting

If the same argument is passed twice to the same function

* Primary: the first expression occurence
message: 'Refactor this assertion to not pass the same argument twice.'

* Secondary: the second expression occurence
message: 'Argument [POSITION] has the same value.'


If the assertion is of the form ``++expect(obj).a(obj, other1)++``

* Primary: the duplicate argument.
message: 'Refactor this assertion to not pass the same value as in "expect()".'

* Secondary: the argument of "expect".

If the assertion is of the form ``++obj.should.be.closeTo(obj, other1, other2)++``

* Primary: the duplicate argument.
message: Refactor this assertion to not use the same value as the one asserted by "should".

* Secondary: the variable on which "should" is called.
no message


'''
== Comments And Links
(visible only on this page)

include::../comments-and-links.adoc[]

endif::env-github,rspecator-view[]