Add to Testing docs to make more clear

[kickinbahk]

When going through the docs, it is not clear that binary files cannot be tested. Additionally, it is hard to find the proper structure of a Rust crate and it took me several hours of looking through the docs to find the crates and modules section. I think we can link to it from here and it will be beneficial to those who are coming to the language.

[rust-highfive]

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[steveklabnik]

A few things:

1. Can you make the link relative, please. See the line right about your diff.
2. Section should be lower case, at the end of the sentence.
3. End with a period please!
4. I mean, you can run tests on a binary, you can't urn unit tests defined in the binary. You can test binaries through integration tests. So I'm not sure about this wording.
5. I would prefer to just remove the main bit, and make it "a binary" rather than "the binary (main) file"

[steveklabnik]

Some nits! I do think this is a good improvement 👍

[kickinbahk]

@steveklabnik thanks for the feedback. I will definitely change 1-3.

I was having trouble running tests from a tests directory on a binary or main.rs file and based off the feedback in IRC as well as the docs, it made it seem that it is not possible. Rather, would need to have the code in a lib.rs file for it to be tested and call that from the main.rs file. If I am not correct on any of this understanding, I would love for further clarification.

I think the part that I am not clear on is "You can test binaries through integration tests". Would this be by using an crate rather than the built in test framework?

[steveklabnik]

Well, the lib.rs/main.rs thing is the Cargo convention, but not always true. Like, binaries in src/bins/, for example, which have different names.

Would this be by using an crate rather than the built in test framework?

No, you'd use std::process::Command, basically. I was trying to say that it is possible to test binaries, somehow.

[kickinbahk]

@steveklabnik Thank you for clarifying that. I have made those changes that you recommended.

[steveklabnik]

@bors: r+ rollup

[bors]

📌 Commit cf926f1 has been approved by steveklabnik

[steveklabnik]

Thanks so much!

[bors]

⌛ Testing commit cf926f1 with merge 971856d...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt