fix(tests): restrict 'cat' tests to unix environments. Fixes #776

[ritvikos]

Tests using the cat command are specific to Unix-like environments and will fail on unsupported platforms.
Restrict these tests to unix environments only.

[sharkdp]

Thank you for reporting this and for opening a PR. It would be great if we could test this behavior on Windows somehow. Maybe we can find a Windows replacement for cat? Doesn't need to be a cat-equivalent. Just something that we can pass input to. And check if it received the input correctly.

[ritvikos]

Great idea!
Found that type is the replacement of cat in Windows.
Now the tests work fine 😄

• Stackoverflow - Cat Replacement in Windows
• Microsoft Docs - Type

[sharkdp]

This is not testing the right thing, I believe? The cat test above on Linux makes sure that we can pipe input from example_input_file.txt into the benchmarked command. But this looks to me like you ignore that and simply output the contents if example_input_file.txt using type.

[ritvikos]

type cannot handle stdin like cat, just prints the content of the file.

Whoops! I missed that detail 😅
Nice catch!

Although, found 2 alternatives that can handle pipe stdin on Windows,
let me know if you think it looks acceptable or you want me to look into other alternatives 😄

1. findstr x*: StackOverflow

someprog | findstr x* or any other single character followed by
asterisk copies all lines from the pipe stdin to stdout.

~\Desktop\oss\hyperfine\tests> hyperfine --runs=1 --input=example_input_file.txt --show-output "findstr x*"
Benchmark 1: findstr x*
This text is part of a file
  Time (abs ≡):         21.8 ms               [User: 0.0 ms, System: 4.7 ms]

2. more command: Displays one screen of output at a time.
   Microsoft - More and Unixtutorial.org

~\Desktop\oss\hyperfine\tests> hyperfine --runs=1 --input=example_input_file.txt --show-output "more"
Benchmark 1: more
This text is part of a file
  Time (abs ≡):         16.2 ms               [User: 0.0 ms, System: 5.9 ms]

[sharkdp]

findstr x*: StackOverflow

Thanks for looking into this. I think this is an acceptable hack. We should add a link to that stackoverflow answer to explain what's going on though.

[ritvikos]

Thank you for reviewing this.
Fixed the issue and added the link as well.

[sharkdp]

Thank you. I think we can use something like let command = if cfg!(windows) { … } else { … }; to merge the tests for windows and linux again, to remove some duplication.

[ritvikos]

That makes sense!
How about defining a const for platform-specific standard I/O utility (not sure about naming) with this approach? 🤔

[sharkdp]

Thank you!