__mocks__/fs.js
function writePath(parentDir, path, data) {
    let files = path.split('/');
    let file = files.shift();

    // init file
    if(!parentDir[file]) parentDir[file] = {
        content: undefined,
        tree: {}
    };

    if(files.length > 0) {
        writePath(parentDir[file].tree, files.join('/'), data);
    } else if(data) {
        parentDir[file].content = data.toString();
    }
}
function writePath(parentDir, path, data) {
    let files = path.split('/');
    let file = files.shift();

    // init file
    if(!parentDir[file]) parentDir[file] = {
        content: undefined,
        tree: {}
    };

    if(files.length > 0) {
        writePath(parentDir[file].tree, files.join('/'), data);
    } else if(data) {
        parentDir[file].content = data.toString();
    }
}
Recursively creates a file
@param parentDir
@param path
@param data