.forEach(function (browserName) {
assert(Array.isArray(browsers[browserName]), JSON.stringify(browserName) + ' in ' + name + ' is not a valid browser name.');
var realVersions = browsers[browserName].map(selectVersion);
versions[browserName]
.forEach(function (version) {
assert(realVersions.indexOf(version) !== -1,
JSON.stringify(browserName) + ' in ' + name + ' does not have a version ' + JSON.stringify(version));
});
});