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Test your linter

Add a snapshot test​

At the bottom of the no_unsafe_operation.rs file, add the following:

#[cfg(test)]
mod tests {
    use crate::tests::check_diagnostics;

    #[test]
    fn test_no_unsafe_operation() {
        check_diagnostics(
            r#"
            //- /src/main.erl
            -module(main).
            -export([warn/0]).
            warn() ->
                unsafe:operation(data),
            %%  ^^^^^^^^^^^^^^^^^^^^^^ 💡 warning: Do not use unsafe:operation/1 in production code.
                safe:operation(data).
            //- /src/unsafe.erl
            -module(unsafe).
            -export([operation/1]).
            operation(_) -> ok.
            //- /src/safe.erl
            -module(safe).
            -export([operation/1]).
            operation(_) -> ok.
            "#,
        );
    }
}

ELP uses convenient snapshot tests for checking diagnostics. The test above checks that the diagnostic is correctly reported when calling unsafe:operation/1. It also checks that the diagnostic is not reported when calling safe:operation/1.

Always include comprehensive tests in your diagnostic module:

  1. Positive cases - Code that should trigger the diagnostic
  2. Negative cases - Similar code that should NOT trigger the diagnostic
  3. Edge cases - Boundary conditions and unusual syntax

You can run the tests with the following command:

cargo test --package elp_ide --lib -- diagnostics::no_unsafe_operation::tests::test_no_unsafe_operation --exact --show-output

Try the new linter from the CLI​

You can also try the new linter against a hypothetical my_module Erlang module:

cargo run --bin elp -- lint --project /path/to/your/project --module my_module --diagnostic-filter no_unsafe_operation
Diagnostics reported in 1 modules:
  my_module: 1
      29:4-29:25::[Warning] [W0055] Do not use unsafe:operation/1 in production code.