英文:
go test `-parallel` vs `-test.parallel` which flag gets precedence?
问题
go test命令的两个标志-parallel和-test.parallel之间的区别是什么？哪个标志优先级更高？
-parallel n标志允许并行执行调用了t.Parallel的测试函数。该标志的值是同时运行的最大测试数；默认情况下，它设置为GOMAXPROCS的值。需要注意的是，-parallel仅适用于单个测试二进制文件。根据-p标志的设置（参见go help build），go test命令也可以并行运行不同包的测试。
上述文档说明，如果未提供任何值，则并行运行的测试数等于GOMAXPROCS的值，但对于我来说，行为并非如此。因为我在一台只有4个核心的机器上运行测试。但是对我来说，有8个测试并行运行，所以行为更像是以下内容：
-test.parallel int标志表示最大测试并行性（默认值为8）。
所以这两者之间有什么区别？何时使用哪个标志。
更多信息
我正在对一个单独的包运行所有测试，该包有9个测试，所有这些测试都在单个测试函数中并行运行。
英文:
Difference between go test's two flags -parallel and -test.parallel and which flag gets precedence?
-parallel n
Allow parallel execution of test functions that call t.Parallel.
The value of this flag is the maximum number of tests to run
simultaneously; by default, it is set to the value of GOMAXPROCS.
Note that -parallel only applies within a single test binary.
The 'go test' command may run tests for different packages
in parallel as well, according to the setting of the -p flag
(see 'go help build').
Above documentation says that the number of tests that are run in parallel are equal to GOMAXPROCS if nothing is provided, but the behavior is not like that for me. Because I am running tests on a machine that has only 4 cores. But for me 8 tests run in parallel, so the behavior is more like following:
-test.parallel int
maximum test parallelism (default 8)
So what is the difference between the two? When to use which flag.
More Information
I am running all tests on a single package which has 9 tests, all of them are run parallely and all those exist in single test function.
答案1
得分: 10
-test. 标志是由 go test 命令生成的。go test 命令会即时生成一个 pkg.test 二进制文件，并使用修改后的参数运行它。所有被识别的传递给 go test 的参数都会被转换。所以，在你的情况下：-parallel n 会变成 -test.parallel n。
因此，这个命令：
go test -parallel 6
会生成：
pkg.test -test.parallel 6
英文:
The -test. flags are generated by go test command. The go test command produces a pkg.test binary on the fly and runs it with modified arguments. All the recognized arguments passed to go test will be converted. So, in your case: -parallel n becomes -test.parallel n.
So this command:
go test -parallel 6
creates:
pkg.test -test.parallel 6
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