我应该使用std :: system来编写单元测试的脚本吗？

Question

I'm in the situation that I have a unit test for a C++ tool where part of the tests need to actually run a test-commandline-tool (that will then trigger something I can check in the test once the test-tool has ended).

I think the C++ Unit Testing Framework I use is quite irrelevant, my question pertains to the legitimate use of system("test_tool.exe ...") -- it would seem that system isn't on the top tool list for C++ developers (and rightly so in general, IMHO).

So, is system known to be used successfully in Unit Tests? Should I expect any problem when using it to execute a well-known tool in a UT environment?

Answer 1

To me, this is an acceptable use of system - but you will need to be careful about "how do you check that the test_tool did what is said it would.

However, hopefully your overall test system has reasonable security, so malicious users should be less of an issue than a general use of system in a random application.

Of course, it also wouldn't be that hard to write some code that uses CreateProcess or another "less evil" variant than system . Using this will probably also give you a bit more flexibility and control over the newly started process - eg you can monitor the process and tell when it finished and what status it exited with, including detecting if it exited nicely or crashed.

Answer 2

If test_tool is a tool you've installed, there shouldn't be any problem. What you want to avoid is using system with a string which even partially comes from user input (unless you've really vetted that input), and using it to invoke system specific commands (since your portability goes down the drain). With regards to the latter, you might want to invoke the test using system( "test_tool ..." ) , without the .exe .