Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::redundant_test_prefix: Checks for test functions (functions annotated with #[test]) that are prefixed with test_ which is redundant

What it meansChecks for test functions (functions annotated with #[test]) that are prefixed with test_ which is redundant. It is in the restriction group and off by default.

Does it matter?

This is redundant because test functions are already annotated with #[test]. Moreover, it clutters the output of cargo test since test functions are expanded as module::tests::test_use_case in the output. Without the redundant prefix, the output becomes module::tests::use_case, which is more readable.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

Clippy does not fix this one automatically (its suggestion may change behaviour, so it only shows it). Change the code by hand:

Flagged

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn test_use_case() {
      // test code
  }
}

Write this instead

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn use_case() {
      // test code
  }
}

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

Whole crate (Cargo.toml)

[lints.clippy]
redundant_test_prefix = "warn"

In code

#![warn(clippy::redundant_test_prefix)]

One run

cargo clippy -- -W clippy::redundant-test-prefix

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.

Restrictiongroup

allowdefault level

nofixed by cargo clippy --fix

1.88.0added in Rust

Clippy's own documentation

What it does

Checks for test functions (functions annotated with #[test]) that are prefixed with test_ which is redundant.

Why is this bad?

This is redundant because test functions are already annotated with #[test]. Moreover, it clutters the output of cargo test since test functions are expanded as module::tests::test_use_case in the output. Without the redundant prefix, the output becomes module::tests::use_case, which is more readable.

Example

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn test_use_case() {
      // test code
  }
}

Use instead:

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn use_case() {
      // test code
  }
}

Note

Clippy can only lint compiled code. For this lint to trigger, you must configure cargo clippy to include test compilation, for instance, by using flags such as --tests or --all-targets.

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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