<h2 id="embedded-test-module"><a href="#embedded-test-module" aria-hidden="true" tabindex="-1"></a>Embedded test module</h2>
These tests can interact with private variables. Unit tests go here.
<div class="remark-highlight"><pre class="language-rust"><code class="language-rust">// Some code I want to test

#[cfg(test)]
mod tests {
 // Import the code I want to test
 use super::*;

 // My tests
}
</code></pre></div>
<h2 id="external-tests-folder"><a href="#external-tests-folder" aria-hidden="true" tabindex="-1"></a>External <code>tests</code> folder</h2>
These tests have the same level of access as an external crate importing this one. Integration tests go here.
<div class="remark-highlight"><pre class="language-bash"><code class="language-bash">➜ ls
src/
tests/
Cargo.toml
Cargo.lock
...
</code></pre></div>
Combine all tests into one module - <code>crate/tests/integration/*</code> instead of multiple <code>.rs</code> files in <code>crate/tests/</code>. Otherwise, each individual file is compiled into a separate binary.
<ol start="3">
<li>Doc</li>
</ol>
Same level of access as #2
<div class="remark-highlight"><pre class="language-rust"><code class="language-rust">/// Check if a number is even.
/// ```rust
/// use zero2prod::is_even;
///
/// assert!(is_even(2));
/// assert!(!is_even(1));
/// ```
pub fn is_even(x: u64) -> bool {
 x % 2 == 0 
}
</code></pre></div>
Sources
<ul>
<li><a href="http://zero2prod.com">Zero to Production in Rust</a></li>
<li><a href="https://matklad.github.io/2021/02/27/delete-cargo-integration-tests.html">Delete Cargo Integration Tests</a></li>
</ul>

Embedded test module
These tests can interact with private variables. Unit tests go here.
// Some code I want to test

\#\[cfg(test)]
mod tests {
// Import the code I want to test
use super::\*;

 // My tests

}


External tests folder
These tests have the same level of access as an external crate importing this one. Integration tests go here.
➜ ls
src/
tests/
Cargo.toml
Cargo.lock
...

Combine all tests into one module - crate/tests/integration/* instead of multiple .rs files in crate/tests/. Otherwise, each individual file is compiled into a separate binary.

Doc

Same level of access as #2
/// Check if a number is even.
/// ```rust
/// use zero2prod::is_even;
///
/// assert!(is_even(2));
/// assert!(!is_even(1));
/// ```
pub fn is_even(x: u64) -> bool {
 x % 2 == 0 
}

Sources

Zero to Production in Rust
Delete Cargo Integration Tests

Rust test folder location

Embedded test module

External `tests` folder