问题描述

我正在使用 Mocha 来测试我的应用程序.目前，我正在使用 Makefiles，但我想切换到 Cakefiles.当我通过 Cake 运行测试时，来自 Mocha 的颜色不会显示在控制台上.

I'm using Mocha for testing my apps. Currently, I'm using Makefiles, but I want to switch to Cakefiles. When I run my test through Cake, the colors from Mocha are not displayed on console.

这是一个例子:

task 'test', 'test project', (options) ->
  fetchTestFiles './test', (err,files) ->
    mocha = spawn 'mocha', files   
    mocha.stdout.pipe(process.stdout, end: false)

现在，我尝试这样做:

task 'test', 'test project', (options) ->
  fetchTestFiles './test', (err,files) ->
    mocha = spawn 'mocha', files, customFds: [0..2]

这可行，但是 Node.js 文档声称 customFds 已被弃用.有没有办法在不使用 customFds 的情况下通过颜色?

This works, however the Node.js docs claim that customFds is deprecated. Is there a way to pass through the colors without using customFds?

推荐答案

问题是 mocha 和许多命令行程序一样，如果它看到输出到的不是终端，就会禁用颜色输出.这样做是因为如果您通过管道传输到文件，则该文件将充满颜色控制序列以及显示的文本.

The problem is that mocha, like many command line programs, will disable color output if it sees that the thing it is outputting to is not a terminal. It does this because otherwise if you piped to a file, the file would be full of color control sequences along with the displayed text.

所以问题不在于 node，而更多在于 mocha.这种情况下的解决方案是 mocha 有一个 --colors 参数来强制颜色输出.所以这应该可行.

So the issue isn't really with node, and more with mocha. The solution in this case is that mocha has a --colors argument to force color output. So this should work.

task 'test', 'test project', (options) ->
  fetchTestFiles './test', (err,files) ->
    files.unshift '--colors'
    mocha = spawn 'mocha', files   
    mocha.stdout.pipe(process.stdout, end: false)

通常，当您生成一个进程时，会为子进程的 stdin、stdout 和 stderr 分配新的数据流.这意味着 mocha 将检查这些流，确定它们不是终端，并禁用颜色.customFds 起作用的原因是它传递了节点在 process.stdin、process.stdout 和 process 处获得的确切流.stderr 到子进程，所以当 mocha 检查流是否是终端时，它们将是因为流是实际的终端.

Normally when you spawn a process, new data streams are allocated for the child's stdin, stdout, and stderr. That means that mocha will check these streams, see that they are not terminals, and disable colors. The reason that customFds works is that it passes the exact streams that node gets at process.stdin, process.stdout, and process.stderr to the child process, so when mocha checks if the streams are terminals, they will be because the streams are the actual terminal.

我知道您正在寻找另一种解决方案，但我认为您不会找到.您要么明确告诉 mocha 使用颜色，要么 mocha 需要认为它的流是终端，唯一真正的方法是通过 customFds，正如你所说的那样已弃用.

I know you're looking for another solution, but I don't think you'll find one. You either explicitly tell mocha to use colors, or mocha needs to think that it's streams are terminals, and the only real way to do that is via customFds, which is deprecated as you said.

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