Running with tests that don't use mockfs

[jamchamb]

I had some issues running unit tests (in mocha) with a mock-fs setup for a module that was also included in other tested modules, whose tests did not make use of mock-fs. This would only happen if the tests that did not use mock-fs ran first - so it seemed there was an issue with non-overridden modules being cached.

My solution was to add this to the top of test files that used mock-fs:

// Clear require cache to make sure mock-fs works
Object.keys(require.cache).forEach(function (key) {delete require.cache[key];}); 

I'm wondering if there's a better way to do this, or if it would be helpful to add this to the documentation?

[goliney]

I have faced the same problem. Would love to see elegant way to get round.

[tschaub]

It would be useful to see a simple example that reproduces the issue.

[goliney]

Here is an example that reproduces the issue: https://github.com/goliney/mock-fs-103
Long story short: it is reproducible with fs-extra. With standard fs everything works fine.

/* A.js - runs first */
const expect = require('chai').expect;
//const mock = require('mock-fs');      //uncommenting this line solves the problem
const fs = require('fs-extra');

describe('Dummy test A', function () {
    it('should pass', function () {
        expect(true).to.be.true;
    });
});

/* B.js - runs after */
const expect = require('chai').expect;
const mock = require('mock-fs');
const fs = require('fs-extra');

describe('Dummy test B', function () {
    before(function () {
        mock({
            folder: {}
        });
    });

    after(function () {
        mock.restore();
    });

    it('should read mocked directory', function () {
        var content = fs.readdirSync('folder');
        expect(content).to.be.an.array;
    });
});

[tschaub]

Thanks for the report @jamchamb and for the excellent example setup @goliney.

I've adapted @jamchamb's require cache clearing suggestion in 51bc0fb and pulled in @goliney's example as regression tests in 97c89a5.

I'll cut a release with those changes if tests pass everywhere.

[tschaub]

Looks like fs-extra breaks Node 0.8 support. We could drop Node 0.8 and publish a new major version or write a regression test that doesn't require fs-extra. I'll take a shot at the latter.

[tschaub]

Ok. That got boring. I pushed another change to stop running tests on Node 0.8.

[tschaub]

I've reverted #141 since it introduced new problems. Will need to revisit this.

[kevincaradant]

Hi @tschaub,

I met the same problem, every files can't be found with fs-extra. Do you any news about it ? :)

thank you

[LeoK80]

testing with jest I've been able to isolate mock-fs to a describe block and simply call mock() in the beforeEach() section and mock.restore() in the afterEach() section for the tests within the describe block using mock-fs.