Clippy lints / Restriction
Clippy lint · Restriction · checked with Clippy 0.1.99
clippy::cfg_not_test: code is excluded from test builds
What it meansChecks for usage of cfg that excludes code from test builds. (i.e., #[cfg(not(test))]) It is in the restriction group and off by default.
What you see
warning: code is excluded from test builds --> main.rs:3:1 | 3 | #[cfg(not(test))] | ^^^^^^^^^^^^^^^^^ | = help: consider not excluding any code from test builds = note: this could increase code coverage despite not actually being tested = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#cfg_not_test = note: requested on the command line with `-W clippy::cfg-not-test`
Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.
Does it matter?
This may give the false impression that a codebase has 100% coverage, yet actually has untested code. Enabling this also guards against excessive mockery as well, which is an anti-pattern.
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. Change the code by hand:
Flagged
#[cfg(not(test))]
important_check(); // I'm not actually tested, but not including me will falsely increase coverage!
Write this instead
important_check();
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]
cfg_not_test = "warn"In code
#![warn(clippy::cfg_not_test)]One run
cargo clippy -- -W clippy::cfg-not-testThe [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.
Clippy's own documentation
What it does
Checks for usage of cfg that excludes code from test builds. (i.e., #[cfg(not(test))])
Why is this bad?
This may give the false impression that a codebase has 100% coverage, yet actually has untested code. Enabling this also guards against excessive mockery as well, which is an anti-pattern.
Example
#[cfg(not(test))]
important_check(); // I'm not actually tested, but not including me will falsely increase coverage!
Use instead:
important_check();
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- unwrap_usedChecks for .unwrap() or .unwrap_err() calls on Results and .unwrap() call on Options
- module_name_repetitionsDetects public item names that are prefixed or suffixed by the containing public module’s name
- expect_usedChecks for .expect() or .expect_err() calls on Results and .expect() call on Options
- as_underscoreusing `as _` conversion
- assertions_on_result_statesChecks for assert!(r.is_ok()) or assert!(r.is_err()) calls
- big_endian_bytesuse of `to_be_bytes`
- clone_on_ref_ptrChecks for usage of .clone() on a ref-counted pointer, (Rc, Arc, rc::Weak, or sync::Weak), and suggests calling Clone via unified function syntax instead (e.g., Rc::clone(foo))
- cognitive_complexityWe used to think it measured how hard a method is to understand
- create_dircalling `std::fs::create_dir` where there may be a better way
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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