sealed_test 0.2.0

Sealed test

This crate expose the #[sealed_test] macro attribute to run your test in an isolated environment.

It provides the following :

• an isolated process using rusty-fork and
• a temporary work dir tempfile.

Caution: using #[sealed_test] instead of #[test] will create a temporary file and set it to be the test current directory but, nothing stops you from changing that directory using std::env::set_current_dir.

Example

Without sealed_test :

The below bar test will fail because the environment variable will be concurrently altered by the foo test.

#[test]
fn foo() -> Result<(), VarError> {
   std::env::set_var("VAR", "foo");
   let var = std::env::var("VAR")?;
   assert_eq!(var, "foo");
   Ok(())
}

#[test]
fn bar() -> Result<(), VarError> {
    std::env::set_var("VAR", "bar");
    // During the thread sleep, the `foo` test will run
    // and set the environment variable to "foo"
    std::thread::sleep(Duration::from_secs(1));
    let var = std::env::var("VAR")?;
    // If running tests on multiple threads the below assertion will fail
    assert_eq!(var, "bar");
    Ok(())
}

With sealed_test :

Here each test has its own environment, the tests will always pass.

use sealed_test::prelude::*;

#[sealed_test]
fn foo() -> Result<(), VarError> {
   std::env::set_var("VAR", "bar");
    let var = std::env::var("VAR")?;
    assert_eq!(var, "bar");
    Ok(())
}

#[sealed_test]
fn bar() -> Result<(), VarError> {
    std::env::set_var("VAR", "bar");
    std::thread::sleep(Duration::from_secs(1));
    let var = std::env::var("VAR")?;
    assert_eq!(var, "bar");
    Ok(())
}