我正在尝试编写一个使用fs.watch方法而不是watchFile方法的较新的监视模块。
到目前为止，它运行得很漂亮，但只有当我在摩卡之外运行它。我无法弄清楚为什么我的单元测试会发脾气，也许有人在这里可以吗？
这是我的班级代码：
/**
* requirements
*/
var fs, path, events;
fs = require('fs');
path = require('path');
events = require('events');
/**
* private
*/
var Monitor = function(directory, options) {
this.directory = directory;
this.options = options || {};
(this.options.lazy && this.empty()) || this.walk(this.directory);
this.watch(this.directory);
};
Monitor.prototype = new events.EventEmitter();
Monitor.prototype.watch = function(directory, stats) {
var stats = stats || {};
if (!this.directories[directory]) {
var w = fs.watch(directory, this.options, this.justlookatit.bind(this));
}
this.directories[directory] = { 'stats': stats, 'w': w };
};
Monitor.prototype.directories = function() {
if (!Object.keys(this.directories).length) {
this.walk(this.directory);
}
return this.directories;
};
Monitor.prototype.files = function() {
if (!Object.keys(this.files).length) {
this.walk(this.directory);
}
return this.files;
};
Monitor.prototype.unwatch = function() {
if (!Object.keys(this.directories).length) {
for (var dir in this.directories) {
dir.w.close();
}
}
};
Monitor.prototype.empty = function() {
this.unwatch();
this.files = {};
this.directories = {};
};
Monitor.prototype.walk = function(directory) {
var monitor = this;
this.empty();
fs.readdir(directory, function(err, files) {
if (err) return;
for (var file in files) {
var fullname = path.resolve(files[file]);
if (!monitor.options.filter || monitor.options.filter(fullname)) {
fs.stat(fullname, function(err, stats) {
if (err) return;
if (stats.isDirectory()) {
monitor.walk(fullname);
monitor.watch(fullname, stats);
} else {
monitor.files[fullname] = stats;
}
});
}
}
});
};
Monitor.prototype.justlookatit = function(action, file) {
var monitor = this;
var fullname = path.resolve(file);
if (this.options.filter && !this.options.filer(fullname)) return;
fs.exists(fullname, function(exists) {
if (exists) {
fs.stat(fullname, function(err, stats) {
if (stats.isDirectory()) {
monitor.watch(fullname, stats);
} else {
if (monitor.files[fullname]) {
if (stats.mtime.getTime() > monitor.files[fullname].mtime.getTime()) {
monitor.emit('modified', fullname, stats);
}
} else {
monitor.emit('added', fullname, stats);
}
monitor.files[fullname] = stats;
}
});
} else {
if (monitor.files[fullname]) {
delete monitor.files[fullname];
monitor.emit('deleted', fullname);
} else if (monitor.directories[fullname]) {
monitor.directories[fullname].w.close();
delete monitor.directories[fullname];
}
}
});
};
/**
* exports
*/
exports.start = function(directory, options) {
return new Monitor(directory, options);
};
这是我的工作外部测试代码：
var watch = require("./watch.js");
var fs = require('fs');
monitor = watch.start(__dirname);
monitor.on('added', function(file, stats) {
console.log("Caught Added: " + file);
});
monitor.on('modified', function(file, stats) {
console.log("Caught Modified: " + file);
});
monitor.on('deleted', function(file) {
console.log("Caught deleted: " + file);
});
// try creating a file immediately
fs.openSync('v.md', 'w');
第一个测试文件运行得很好，我已经尝试了openSync和open。最后，这是一个相同测试代码的版本，包含在一个超时的mocha单元测试中：
/**
* requirements
*/
var watch, Q, fs, path, mocha, chai, assert;
watch = require('../lib/watch.js');
Q = require('q');
fs = require('fs');
path = require('path');
mocha = require('mocha');
chai = require('chai');
assert = chai.assert;
/**
* variables
*/
var watch_directory = path.join(__dirname, './watch');
/**
* tests
*/
describe('test watch', function() {
it('should create a monitor and run callbacks after fs changes', function(done) {
// I had planned to implement promises that chained the three callbacks
// but couldn't get one of them working in general
var added = function(file, stats) {
console.log("added");
done();
};
var modified = function(file, stats) {
console.log("modified");
};
var deleted = function(file, stats) {
console.log("deleted");
};
// create our service
var monitor = watch.start(watch_directory);
// assert it is defined
assert.isDefined(monitor);
// establish a listener
monitor.on('added', added);
monitor.on('modified', modified);
monitor.on('deleted', deleted);
// here is a file name using the current date to prevent duplication during tests
var file = path.join(watch_directory, (new Date()).getTime() + '.md');
// let's create the file, then delete it
fs.open(file, 'w+', function(err, fileDescriptor) {
// this prints before console output from the watch.js's `justlookatit` method
console.log(err);
console.log("writing to file");
// we probably don't want to try closing the fileDescriptor if the open failed
if (err) return;
// close the file descriptor
fs.close(fileDescriptor, function() {
// delete the file we just created
// fs.unlink(file, function() { /* not a big deal */ });
});
});
// modify a known-existing test file
fs.open('test.md', 'w+', function() {/* we don't care about this */});
})
});
我在监视代码的console.log(fullname)方法中使用justlookatit进行了检查，并且它会显示正确的文件名，与单元测试生成的文件名相匹配。
然而，当我运行false时，它会继续返回fs.exists。正如我所说，这意味着文件系统通知我文件存在之前存在，这实际上没有意义。因此，我尝试通过将fs.exists方法包装在setTimeout中来添加额外延迟，但这并没有改变结果。我也尝试过使用openSync和existsSync，但没有区别。
我很难过，有没有人知道为什么摩卡代码不起作用？
答案 0 :(得分：0)
所以，解决方案是去散步。我回来了，再次查看代码并找出了mocha问题的原因，并发现了许多其他错误。
问题在于缺乏背景。 justlookatit方法没有上下文，并且在test.js方案中它正在观看当前目录，而mocha测试正在观看子目录。
path.resolve只接收文件名，而不是目录，因此将其与默认（可执行文件）目录合并，因此mocha的级别为test.js或watch_test.js 。它继续找不到mocha测试用例中的任何文件，因为它们都比可执行文件低一级。
我不会详细了解所有其他错误，但是当我到达我希望将其推送到网上的点时，我可能会回来并发布存储库链接。
答案 1 :(得分：-1)
您在测试结束时错过了回调return(done);。除非你打电话给那个回调，否则摩卡每次都会超时。