Java - 单元测试

Question

在Java类中给出此方法:

public void execute(String command) {

    ProcessBuilder processBuilder = new ProcessBuilder(command);
    Process process = processBuilder.start();

    int exitValue = process.waitFor();
    if (exitValue != 0) {
        throw new RuntimeException("a message here...");
    }
}

我正在尝试为这种方法提出适当的跨平台单元测试.

我正在寻找所有操作系统(Win,Linux,Mac和...)的常用命令,或者我可以在单元测试中传递给此方法的假命令.

有什么建议吗？

Answer 1

此方法无法通过单元测试进行测试,只能通过集成测试进行测试.要进行单元测试,你可以做一个小型的重构.引入一个新接口ProcessBuilderFactory(和一个默认实现)并将其注入您的类.

public interface ProcessBuilderFactory {
    ProcessBuilder createProcessBuilder(String command);
}

public class DefaultProcessBuilderFactory implements ProcessBuilderFactory {
    public ProcessBuilder createProcessBuilder(String command) {
        return new ProcessBuilder(command);
    }
}

public class ProcessExecutor {
    private ProcessBuilderFactory processBuilderFactory;
    private ProcessExecutor(ProcessBuilderFactory processBuilderFactory) {
        this.processBuilderFactory = processBuilderFactory;
    }

    public void execute(String command) {
        ProcessBuilder processBuilder = processBuilderFactory.createProcessBuilder(command);
        Process process = processBuilder.start();

        int exitValue = process.waitFor();
        if (exitValue != 0) {
            throw new RuntimeException("a message here...");
        }
    }
}

然后你可以通过注入模拟进行单元测试ProcessBuilderFactory.你开始写测试,你创建一个模拟ProcessBuilderFactory,并返回一个模拟ProcessBuilder...该死的,ProcessBuilder是final太:(

强烈提醒:先写测试!

所以我们有两个选择:

1. 引入一个新的接口来包装ProcessBuilder默认实现...就像我们创建的一样ProcessBuilderFactory
2. 撤消重构并查看PowerMock,以进行最终的类模拟