Boost :: Process Pipe Streams和单元测试 [英] Boost::Process Pipe Streams and Unit Test

问题描述

我有像这样的两个流的来源:

I have source which two stream like this:

bp::ipstream StdOut;
bp::opstream StdIn;
bp::child MyProcess = bp::child(processPath, bp::std_out > StdOut, bp::std_in < StdIn);
// Doing some stuff with StdOut and StdIn

我想知道是否有一种方法可以手动写入此StdOut并从StdIn读取以进行单元测试?非常感谢你！

I wanted to know if there is a way to write manually into this StdOut and read from StdIn in order to do unit tests? Thank you very much!

推荐答案

您可以将它们作为普通流写入其中:

You can write to them as a normal stream:

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#include <boost/process.hpp>
#include <iostream>

namespace bp = boost::process;

int main() {
    bp::ipstream StdOut;
    bp::opstream StdIn;
    bp::child MyProcess = bp::child("/usr/bin/rev", bp::std_out > StdOut, bp::std_in < StdIn);

    for (int i = 0; i<100; ++i) {
        StdIn << "Sure no problem, " << i << std::endl;
    }
    StdIn.flush();
    StdIn.pipe().close();

    std::string il;
    while (getline(StdOut, il)) {
        std::cout << il << std::endl;
    }

    std::cout << "Bye\n";
}

打印

0 ,melborp on eruS
1 ,melborp on eruS
2 ,melborp on eruS
...
99 ,melborp on eruS
Bye

异步版本

请注意，就像文档警告一样，如果您的进程需要异步IO，则可能导致死锁(例如，子进程正在等待输入时等待输出).

Async Version

Note, like the documentation warns, if your process requires async IO you could end up deadlocking (e.g. waiting for output while the child process is waiting for input).

要实现此目的，请使用Asio的异步操作:

To achieve this, use Asio's asynchronous operations:

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#include <boost/process.hpp>
#include <boost/asio.hpp>
#include <boost/process/async.hpp>
#include <iostream>

namespace ba = boost::asio;
namespace bp = boost::process;

int main() {
    ba::io_context io;
    bp::async_pipe ip(io), op(io);
    //bp::async_pipe StdIn(io);

    bp::child MyProcess = bp::child("/usr/bin/tac", bp::std_out > op, bp::std_in < ip, io);

    std::function<void()> send_loop, recv_loop;

    ba::streambuf sb;
    send_loop = [&, i=0]() mutable {
        if (++i<100) {
            std::ostream(&sb) << "Sure no problem, " << i << std::endl;
            ba::async_write(ip, sb, [&send_loop](auto ec, auto /*tx*/) {
                //std::cout << "Sent " << tx << " bytes (" << ec.message() << ")\n";
                if (!ec) send_loop();
            });
        } else ip.close();
    };

    ba::streambuf rb;
    recv_loop = [&]() {
        ba::async_read_until(op, rb, "\n", [&](auto ec, auto /*tx*/) {
            //std::cout << "Received " << tx << " bytes (" << ec.message() << ")\n";
            std::cout << &rb << std::flush;
            if (!ec) recv_loop();
        });
    };

    io.post(send_loop);
    io.post(recv_loop);
    io.run();

    std::cout << "Bye\n";
}

打印预期结果:

Sure no problem, 99
Sure no problem, 98
Sure no problem, 97
Sure no problem, 96
Sure no problem, 95
Sure no problem, 94
Sure no problem, 93
Sure no problem, 92
Sure no problem, 91
Sure no problem, 90
Sure no problem, 89
Sure no problem, 88
Sure no problem, 87
Sure no problem, 86
Sure no problem, 85
Sure no problem, 84
Sure no problem, 83
Sure no problem, 82
Sure no problem, 81
Sure no problem, 80
Sure no problem, 79
Sure no problem, 78
Sure no problem, 77
Sure no problem, 76
Sure no problem, 75
Sure no problem, 74
Sure no problem, 73
Sure no problem, 72
Sure no problem, 71
Sure no problem, 70
Sure no problem, 69
Sure no problem, 68
Sure no problem, 67
Sure no problem, 66
Sure no problem, 65
Sure no problem, 64
Sure no problem, 63
Sure no problem, 62
Sure no problem, 61
Sure no problem, 60
Sure no problem, 59
Sure no problem, 58
Sure no problem, 57
Sure no problem, 56
Sure no problem, 55
Sure no problem, 54
Sure no problem, 53
Sure no problem, 52
Sure no problem, 51
Sure no problem, 50
Sure no problem, 49
Sure no problem, 48
Sure no problem, 47
Sure no problem, 46
Sure no problem, 45
Sure no problem, 44
Sure no problem, 43
Sure no problem, 42
Sure no problem, 41
Sure no problem, 40
Sure no problem, 39
Sure no problem, 38
Sure no problem, 37
Sure no problem, 36
Sure no problem, 35
Sure no problem, 34
Sure no problem, 33
Sure no problem, 32
Sure no problem, 31
Sure no problem, 30
Sure no problem, 29
Sure no problem, 28
Sure no problem, 27
Sure no problem, 26
Sure no problem, 25
Sure no problem, 24
Sure no problem, 23
Sure no problem, 22
Sure no problem, 21
Sure no problem, 20
Sure no problem, 19
Sure no problem, 18
Sure no problem, 17
Sure no problem, 16
Sure no problem, 15
Sure no problem, 14
Sure no problem, 13
Sure no problem, 12
Sure no problem, 11
Sure no problem, 10
Sure no problem, 9
Sure no problem, 8
Sure no problem, 7
Sure no problem, 6
Sure no problem, 5
Sure no problem, 4
Sure no problem, 3
Sure no problem, 2
Sure no problem, 1
Sure no problem, 1

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