Tribute Testing Guide

Running Tests

cargo nextest run --workspace           # All tests (preferred)
cargo nextest run -p tribute            # Specific crate
cargo nextest run -p tree-sitter-tribute
cargo nextest run -p tribute-passes
cargo nextest run -p trunk-ir
cargo insta review                      # Review snapshot test failures

Salsa Test Patterns

#[salsa_test] Macro

The #[salsatest] macro from salsatest_macros automatically provides a Salsa database context.

use salsa_test_macros::salsa_test;

#[salsa_test]
fn test_example(db: &salsa::DatabaseImpl) {
    // Test code using db
}

Generated code:

#[test]
fn test_example() {
    salsa::Database::attach(&salsa::DatabaseImpl::default(), |db| {
        // Test code
    });
}

accumulate() Test Constraints

Key constraint: Diagnostic.accumulate(db) must be called inside a #[salsa::tracked] function.

#[salsa_test] attaches a database but does NOT create a tracked function context. Unit tests that directly call code using accumulate() will fail:

cannot accumulate values outside of an active tracked function

Solution: Test diagnostic accumulation at the integration level via tracked queries.

// ❌ Direct accumulate in unit test - FAILS
#[salsa_test]
fn test_unresolved_name(db: &salsa::DatabaseImpl) {
    let resolver = Resolver::new(db, env, span_map);
    resolver.resolve_name(&unresolved);  // calls accumulate() internally → error!
}

// ✅ Integration test via tracked query - WORKS
#[salsa_test]
fn test_diagnostics(db: &salsa::DatabaseImpl) {
    let source = make_source(db, "fn main() { undefined_var }");
    let _module = resolved_module(db, source);  // tracked function
    let diagnostics = resolved_module::accumulated::<Diagnostic>(db, source);
    assert!(!diagnostics.is_empty());
}

Test Level Separation

Snapshot Testing (insta)

use insta::assert_snapshot;

#[test]
fn test_ir_output() {
    let output = compile_to_ir("fn main() { 42 }");
    assert_snapshot!(output);
}

Update snapshots: cargo insta review

Collecting Diagnostics

Collect accumulated Diagnostics from a tracked query:

let diagnostics: Vec<Diagnostic> =
    query_function::accumulated::<Diagnostic>(db, source)
        .into_iter()
        .cloned()
        .collect();

See guides/salsa.md for detailed Salsa usage documentation.