Merge pull request #1547 from waldyrious/patch-1

doc_testing.md: clarify tests vs doc-tests

Author: marioidival

src/testing/doc_testing.md

@@ -3,7 +3,7 @@
 The primary way of documenting a Rust project is through annotating the source
 code. Documentation comments are written in [markdown] and support code
 blocks in them. Rust takes care about correctness, so these code blocks are
-compiled and used as tests.
+compiled and used as documentation tests.
 
 ```rust,ignore
 /// First line is a short summary describing function.
@@ -48,7 +48,8 @@ pub fn div(a: i32, b: i32) -> i32 {
 }
 ```
 
-Tests can be run with `cargo test`:
+Code blocks in documentation are automatically tested
+when running the regular `cargo test` command:
 
 ```shell
 $ cargo test
@@ -73,8 +74,8 @@ the functionality, which is one of the most important
 [guidelines][question-instead-of-unwrap]. It allows using examples from docs as
 complete code snippets. But using `?` makes compilation fail since `main`
 returns `unit`. The ability to hide some source lines from documentation comes
-to the rescue: one may write `fn try_main() -> Result<(), ErrorType>`, hide it and
-`unwrap` it in hidden `main`. Sounds complicated? Here's an example:
+to the rescue: one may write `fn try_main() -> Result<(), ErrorType>`, hide it
+and `unwrap` it in hidden `main`. Sounds complicated? Here's an example:
 
 ```rust,ignore
 /// Using hidden `try_main` in doc tests.