Testing frameworks like Mocha and Jest provide a way to run a single test case for a file by appending .only() to the test function. This is convenient when debugging a specific use case. It makes, however, no sense to have it in production or development, and it was likely left by mistake after such a debugging session. Therefore, it is strongly recommended not to commit usages of .only() to version control.

Noncompliant Code Example

describe("MyClass", function () {
    it.only("should run correctly", function () {
        /*...*/
    });
});

Compliant Solution

describe("MyClass", function () {
    it("should run correctly", function () {
        /*...*/
    });
});

See