load_workspace_at() looks at parent directories. If rust-analyzer is in a directory (e.g. a monorepo) where a parent directory contains a rust-project.json, that configuration wins over the Cargo.toml and the test fails. One easy way of testing this is deliberately writing an invalid JSON file to the parent directory. ``` $ echo '{' > ../rust-project.json $ cargo t -p load-cargo ---- tests::test_loading_rust_analyzer stdout ---- thread 'tests::test_loading_rust_analyzer' (38576150) panicked at crates/load-cargo/src/lib.rs:756:81: called `Result::unwrap()` on an `Err` value: Failed to load the project at /Users/wilfred/src/rust-project.json Caused by: 0: Failed to deserialize json file /Users/wilfred/src/rust-project.json 1: EOF while parsing an object at line 2 column 0 ``` Instead, explicitly load the cargo workspace so the presence of a rust-project.json never changes the result of the test. AI disclosure: Written with help from Claude.