rust_browser/tests/js262_harness/runner.rs

use crate::types::{ExpectedError, Js262Case, Js262Mode, Js262Outcome, Js262Status, Step};
use js::{JsEngine, JsError, OutputSink};
use std::fs;
use std::sync::mpsc;
use std::sync::{Arc, Mutex};
use std::time::Duration;
use web_api::scheduling::Clock;
use web_api::WebApiFacade;

/// Per-test timeout. Tests that take longer are killed and reported as failures.
const TEST_TIMEOUT: Duration = Duration::from_secs(30);

const TEST262_STA: &str = include_str!("../external/js262/test262/harness/sta.js");
const TEST262_ASSERT: &str = include_str!("../external/js262/test262/harness/assert.js");

/// Load a Test262 harness include file by name.
///
/// For "sta.js" and "assert.js", returns the compile-time embedded constants.
/// For anything else, reads from the upstream clone or falls back to vendored harness.
fn load_harness_include(name: &str) -> Result<String, String> {
    match name {
        "sta.js" => Ok(TEST262_STA.to_string()),
        "assert.js" => Ok(TEST262_ASSERT.to_string()),
        _ => {
            let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
            // Try upstream first
            let upstream = manifest_dir
                .join("tests/external/js262/upstream/harness")
                .join(name);
            if upstream.exists() {
                return fs::read_to_string(&upstream).map_err(|e| {
                    format!("failed to read harness include {}: {e}", upstream.display())
                });
            }
            // Fallback to vendored harness
            let vendored = manifest_dir
                .join("tests/external/js262/test262/harness")
                .join(name);
            if vendored.exists() {
                return fs::read_to_string(&vendored).map_err(|e| {
                    format!("failed to read harness include {}: {e}", vendored.display())
                });
            }
            Err(format!(
                "harness include '{name}' not found in upstream or vendored harness directories"
            ))
        }
    }
}

/// A capture sink that can be shared between the engine and the test runner.
struct SharedCaptureSink {
    lines: Arc<Mutex<Vec<String>>>,
}

impl SharedCaptureSink {
    fn new(lines: Arc<Mutex<Vec<String>>>) -> Self {
        Self { lines }
    }
}

impl OutputSink for SharedCaptureSink {
    fn write_line(&mut self, message: &str) {
        self.lines.lock().unwrap().push(message.to_string());
    }
}

pub fn run_case(case: &Js262Case) -> Js262Outcome {
    if let Js262Status::Skip { reason } = &case.status {
        return Js262Outcome::Skipped {
            reason: reason.clone(),
        };
    }

    let script = match fs::read_to_string(&case.input) {
        Ok(v) => v,
        Err(e) => {
            return Js262Outcome::Fail {
                reason: format!("failed to read input {}: {e}", case.input.display()),
            };
        }
    };

    // Run the actual test in a separate thread with a timeout to catch infinite loops.
    let case_clone = case.clone();
    let (tx, rx) = mpsc::channel();
    let handle = std::thread::Builder::new()
        .stack_size(8 * 1024 * 1024)
        .spawn(move || {
            let outcome = match case_clone.mode {
                Js262Mode::Script => run_script_case(&case_clone, &script),
                Js262Mode::Dom => run_dom_case(&case_clone, &script),
                Js262Mode::Test262 => run_test262_case(&case_clone, &script),
            };
            let _ = tx.send(outcome);
        })
        .expect("failed to spawn test runner thread");

    match rx.recv_timeout(TEST_TIMEOUT) {
        Ok(outcome) => {
            let _ = handle.join();
            outcome
        }
        Err(mpsc::RecvTimeoutError::Timeout) => {
            // Thread is stuck — abandon it (it will be cleaned up when the process exits)
            Js262Outcome::Fail {
                reason: format!("test timed out after {}s", TEST_TIMEOUT.as_secs()),
            }
        }
        Err(mpsc::RecvTimeoutError::Disconnected) => Js262Outcome::Fail {
            reason: "test thread panicked".to_string(),
        },
    }
}

fn run_script_case(case: &Js262Case, script: &str) -> Js262Outcome {
    let captured = Arc::new(Mutex::new(Vec::new()));
    let sink = SharedCaptureSink::new(Arc::clone(&captured));
    let mut engine = JsEngine::with_output(Box::new(sink));
    engine.prime_runtime().unwrap();

    let result = engine.execute(script);

    if let Some(expected_error) = case.expected_error {
        return match result {
            Ok(_) => Js262Outcome::Fail {
                reason: format!("expected {:?} error but script succeeded", expected_error),
            },
            Err(err) => {
                if error_matches_class(&err, expected_error) {
                    Js262Outcome::Pass
                } else {
                    Js262Outcome::Fail {
                        reason: format!("expected {:?} error but got: {err}", expected_error),
                    }
                }
            }
        };
    }

    // Output comparison
    if let Err(err) = result {
        return Js262Outcome::Fail {
            reason: format!("script failed: {err}"),
        };
    }

    compare_output_from_captured(case, &captured)
}

fn run_dom_case(case: &Js262Case, script: &str) -> Js262Outcome {
    let captured = Arc::new(Mutex::new(Vec::new()));
    let sink = SharedCaptureSink::new(Arc::clone(&captured));
    let engine = JsEngine::with_output(Box::new(sink));
    let mut facade = WebApiFacade::new_with_engine(engine, Clock::new_virtual());

    // Set up minimal DOM: root > html > body#body > div#target
    {
        let doc = facade.document_mut();
        let root = doc.root().unwrap();
        let html = doc.create_element("html");
        doc.append_child(root, html);
        let body = doc.create_element("body");
        doc.set_attribute(body, "id", "body");
        doc.append_child(html, body);
        let target = doc.create_element("div");
        doc.set_attribute(target, "id", "target");
        doc.append_child(body, target);
    }

    if let Err(e) = facade.bootstrap() {
        return Js262Outcome::Fail {
            reason: format!("bootstrap failed: {e}"),
        };
    }

    if let Err(e) = facade.execute_script(script) {
        if let Some(expected_error) = case.expected_error {
            // Check error class via string matching since SharedResult wraps JsError
            let err_str = e.to_string();
            let class_matches = match expected_error {
                ExpectedError::Parse => err_str.contains("ParseError"),
                ExpectedError::Reference => err_str.contains("ReferenceError"),
                ExpectedError::Type => err_str.contains("TypeError"),
                ExpectedError::Runtime => err_str.contains("RuntimeError"),
            };
            return if class_matches {
                Js262Outcome::Pass
            } else {
                Js262Outcome::Fail {
                    reason: format!("expected {:?} error but got: {err_str}", expected_error),
                }
            };
        }
        return Js262Outcome::Fail {
            reason: format!("script execution failed: {e}"),
        };
    }

    // Execute steps
    for step in &case.steps {
        match step {
            Step::Tick => {
                if let Err(e) = facade.tick() {
                    return Js262Outcome::Fail {
                        reason: format!("tick failed: {e}"),
                    };
                }
            }
            Step::AdvanceMs(ms) => {
                facade.task_queue_mut().clock_mut().advance(*ms);
            }
            Step::DispatchClick(element_id) => {
                let node_id = facade
                    .document()
                    .get_element_by_id(element_id)
                    .unwrap_or_else(|| {
                        panic!("dispatch_click: element with id '{element_id}' not found in DOM")
                    });
                if let Err(e) = facade.dispatch_click(node_id) {
                    return Js262Outcome::Fail {
                        reason: format!("dispatch_click failed: {e}"),
                    };
                }
            }
        }
    }

    // Compare output
    compare_output_from_captured(case, &captured)
}

fn compare_output_from_captured(
    case: &Js262Case,
    captured: &Arc<Mutex<Vec<String>>>,
) -> Js262Outcome {
    let expected_path = match &case.expected_output {
        Some(p) => p,
        None => {
            // No expected output — pass if we got here without errors
            return Js262Outcome::Pass;
        }
    };

    let expected = match fs::read_to_string(expected_path) {
        Ok(v) => v,
        Err(e) => {
            return Js262Outcome::Fail {
                reason: format!(
                    "failed to read expected output {}: {e}",
                    expected_path.display()
                ),
            };
        }
    };

    let lines = captured.lock().unwrap();
    let actual = lines.join("\n");
    let actual = if actual.is_empty() {
        String::new()
    } else {
        format!("{actual}\n")
    };

    let expected = normalize_output(&expected);
    let actual = normalize_output(&actual);

    if actual == expected {
        Js262Outcome::Pass
    } else {
        Js262Outcome::Fail {
            reason: format!(
                "output mismatch for '{}':\n--- expected ---\n{expected}--- actual ---\n{actual}",
                case.id
            ),
        }
    }
}

fn normalize_output(s: &str) -> String {
    let mut out = String::new();
    for line in s.replace("\r\n", "\n").lines() {
        out.push_str(line.trim_end());
        out.push('\n');
    }
    out
}

fn error_matches_class(err: &JsError, expected: ExpectedError) -> bool {
    match expected {
        ExpectedError::Parse => err.is_parse_error(),
        ExpectedError::Reference => err.is_reference_error(),
        ExpectedError::Type => err.is_type_error(),
        ExpectedError::Runtime => err.is_runtime_error(),
    }
}

fn is_test262_assertion_error(err: &JsError) -> bool {
    if let JsError::UncaughtThrow { message } = err {
        message.starts_with("Test262Error:")
    } else {
        false
    }
}

fn run_test262_case(case: &Js262Case, script: &str) -> Js262Outcome {
    // Prepend harness includes, then the test script
    let mut combined = String::new();
    for include_name in &case.includes {
        match load_harness_include(include_name) {
            Ok(src) => {
                combined.push_str(&src);
                combined.push('\n');
            }
            Err(e) => {
                return Js262Outcome::Fail {
                    reason: format!("failed to load harness include: {e}"),
                };
            }
        }
    }
    combined.push_str(script);

    let captured = Arc::new(Mutex::new(Vec::new()));
    let sink = SharedCaptureSink::new(Arc::clone(&captured));
    let mut engine = JsEngine::with_output(Box::new(sink));
    engine.prime_runtime().unwrap();

    let result = engine.execute(&combined);

    if let Some(expected_error) = case.expected_error {
        // Negative test: we expect a specific error class
        return match result {
            Ok(_) => Js262Outcome::Fail {
                reason: format!(
                    "negative test expected {:?} error but script succeeded",
                    expected_error
                ),
            },
            Err(ref err) if is_test262_assertion_error(err) => Js262Outcome::Fail {
                reason: format!(
                    "negative test got Test262 assertion error instead of {:?}: {err}",
                    expected_error
                ),
            },
            Err(ref err) => {
                if error_matches_class(err, expected_error) {
                    Js262Outcome::Pass
                } else {
                    Js262Outcome::Fail {
                        reason: format!(
                            "negative test expected {:?} error but got: {err}",
                            expected_error
                        ),
                    }
                }
            }
        };
    }

    // Positive test: script must complete without error
    match result {
        Ok(_) => Js262Outcome::Pass,
        Err(ref err) if is_test262_assertion_error(err) => Js262Outcome::Fail {
            reason: format!("assertion failed: {err}"),
        },
        Err(err) => Js262Outcome::Fail {
            reason: format!("unexpected error: {err}"),
        },
    }
}

pub fn enforce_case_policy(case: &Js262Case, outcome: Js262Outcome) -> Result<(), String> {
    match (&case.status, outcome) {
        (Js262Status::Pass, Js262Outcome::Pass) => Ok(()),
        (Js262Status::Pass, Js262Outcome::Fail { reason }) => Err(reason),
        (Js262Status::Pass, Js262Outcome::Skipped { reason }) => {
            Err(format!("case '{}' unexpectedly skipped: {reason}", case.id))
        }
        (Js262Status::KnownFail { .. }, Js262Outcome::Fail { .. }) => Ok(()),
        (Js262Status::KnownFail { .. }, Js262Outcome::Pass) => Err(format!(
            "case '{}' is marked known_fail but now passes; promote it to pass in manifest",
            case.id
        )),
        (Js262Status::KnownFail { .. }, Js262Outcome::Skipped { reason }) => Err(format!(
            "case '{}' marked known_fail unexpectedly skipped: {reason}",
            case.id
        )),
        (Js262Status::Skip { .. }, Js262Outcome::Skipped { .. }) => Ok(()),
        (Js262Status::Skip { .. }, Js262Outcome::Pass) => Err(format!(
            "case '{}' marked skip but unexpectedly passed",
            case.id
        )),
        (Js262Status::Skip { .. }, Js262Outcome::Fail { reason }) => Err(format!(
            "case '{}' marked skip but unexpectedly executed and failed: {reason}",
            case.id
        )),
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::types::{ExpectedError, Js262Mode, Js262Status};
    use std::io::Write;

    /// Build a minimal `Js262Case` backed by a temporary JS file containing `script`.
    fn dom_case_with_error(
        script: &str,
        expected_error: ExpectedError,
    ) -> (Js262Case, tempfile::NamedTempFile) {
        let mut tmp = tempfile::NamedTempFile::new().unwrap();
        tmp.write_all(script.as_bytes()).unwrap();
        let case = Js262Case {
            id: "test-dom-error".into(),
            input: tmp.path().to_path_buf(),
            mode: Js262Mode::Dom,
            expected_output: None,
            expected_error: Some(expected_error),
            status: Js262Status::Pass,
            feature: "errors".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        (case, tmp)
    }

    // --- DOM-mode expected_error: correct class → Pass ---

    #[test]
    fn dom_mode_reference_error_with_matching_class_is_pass() {
        // A script that throws a ReferenceError when expected_error = Reference
        // must produce Js262Outcome::Pass.
        let (case, _tmp) = dom_case_with_error("undeclaredVar;", ExpectedError::Reference);
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Pass),
            "expected Pass for matching ReferenceError, got: {outcome:?}"
        );
    }

    #[test]
    fn dom_mode_type_error_with_matching_class_is_pass() {
        // A script that throws a TypeError (const reassignment) when expected_error
        // = Type must produce Js262Outcome::Pass.
        let (case, _tmp) = dom_case_with_error("const c = 1; c = 2;", ExpectedError::Type);
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Pass),
            "expected Pass for matching TypeError, got: {outcome:?}"
        );
    }

    // --- DOM-mode expected_error: wrong class → Fail (not vacuous Pass) ---

    #[test]
    fn dom_mode_wrong_error_class_produces_fail_not_pass() {
        // A script that throws a ReferenceError but expected_error = Type must
        // produce Js262Outcome::Fail.  The old vacuous-pass bug would have
        // returned Pass here.
        let (case, _tmp) = dom_case_with_error("undeclaredVar;", ExpectedError::Type);
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Fail { .. }),
            "expected Fail when error class does not match, got: {outcome:?}"
        );
    }

    #[test]
    fn dom_mode_wrong_error_class_fail_reason_mentions_expected_and_actual() {
        // The Fail reason must identify both the expected class and the actual
        // error so a developer can diagnose the mismatch.
        let (case, _tmp) = dom_case_with_error("undeclaredVar;", ExpectedError::Type);
        let outcome = run_case(&case);
        match outcome {
            Js262Outcome::Fail { reason } => {
                assert!(
                    reason.contains("Type"),
                    "reason should mention expected 'Type', got: {reason}"
                );
                assert!(
                    reason.contains("ReferenceError"),
                    "reason should mention actual 'ReferenceError', got: {reason}"
                );
            }
            other => panic!("expected Fail, got: {other:?}"),
        }
    }

    // --- DOM-mode: no expected_error and script succeeds → Pass ---

    #[test]
    fn dom_mode_no_expected_error_succeeds() {
        // A script with no expected_error that succeeds must produce Pass.
        let mut tmp = tempfile::NamedTempFile::new().unwrap();
        tmp.write_all(b"var x = 1;").unwrap();
        let case = Js262Case {
            id: "test-dom-ok".into(),
            input: tmp.path().to_path_buf(),
            mode: Js262Mode::Dom,
            expected_output: None,
            expected_error: None,
            status: Js262Status::Pass,
            feature: "basics".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Pass),
            "expected Pass for succeeding DOM script, got: {outcome:?}"
        );
    }

    // --- enforce_case_policy: all branches ---

    #[test]
    fn enforce_case_policy_pass_status_pass_outcome_is_ok() {
        let case = Js262Case {
            id: "x".into(),
            input: std::path::PathBuf::new(),
            mode: Js262Mode::Script,
            expected_output: None,
            expected_error: None,
            status: Js262Status::Pass,
            feature: "f".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        assert!(enforce_case_policy(&case, Js262Outcome::Pass).is_ok());
    }

    #[test]
    fn enforce_case_policy_pass_status_fail_outcome_is_err() {
        let case = Js262Case {
            id: "x".into(),
            input: std::path::PathBuf::new(),
            mode: Js262Mode::Script,
            expected_output: None,
            expected_error: None,
            status: Js262Status::Pass,
            feature: "f".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        assert!(enforce_case_policy(
            &case,
            Js262Outcome::Fail {
                reason: "oops".into()
            }
        )
        .is_err());
    }

    #[test]
    fn enforce_case_policy_known_fail_status_fail_outcome_is_ok() {
        let case = Js262Case {
            id: "x".into(),
            input: std::path::PathBuf::new(),
            mode: Js262Mode::Script,
            expected_output: None,
            expected_error: None,
            status: Js262Status::KnownFail {
                reason: "not yet".into(),
            },
            feature: "f".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        assert!(enforce_case_policy(
            &case,
            Js262Outcome::Fail {
                reason: "still broken".into()
            }
        )
        .is_ok());
    }

    #[test]
    fn enforce_case_policy_known_fail_status_pass_outcome_is_err() {
        let case = Js262Case {
            id: "x".into(),
            input: std::path::PathBuf::new(),
            mode: Js262Mode::Script,
            expected_output: None,
            expected_error: None,
            status: Js262Status::KnownFail {
                reason: "not yet".into(),
            },
            feature: "f".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        let err = enforce_case_policy(&case, Js262Outcome::Pass).unwrap_err();
        assert!(
            err.contains("promote"),
            "error should mention promoting the case, got: {err}"
        );
    }

    #[test]
    fn enforce_case_policy_skip_status_skipped_outcome_is_ok() {
        let case = Js262Case {
            id: "x".into(),
            input: std::path::PathBuf::new(),
            mode: Js262Mode::Script,
            expected_output: None,
            expected_error: None,
            status: Js262Status::Skip {
                reason: "needs feature".into(),
            },
            feature: "f".into(),
            steps: vec![],
            includes: vec![],
            flags: vec![],
        };
        assert!(enforce_case_policy(
            &case,
            Js262Outcome::Skipped {
                reason: "needs feature".into()
            }
        )
        .is_ok());
    }

    // --- Test262 runner tests ---

    fn test262_case(
        script: &str,
        expected_error: Option<ExpectedError>,
    ) -> (Js262Case, tempfile::NamedTempFile) {
        let mut tmp = tempfile::NamedTempFile::new().unwrap();
        tmp.write_all(script.as_bytes()).unwrap();
        let case = Js262Case {
            id: "test-t262".into(),
            input: tmp.path().to_path_buf(),
            mode: Js262Mode::Test262,
            expected_output: None,
            expected_error,
            status: Js262Status::Pass,
            feature: "test".into(),
            steps: vec![],
            includes: vec!["sta.js".into(), "assert.js".into()],
            flags: vec![],
        };
        (case, tmp)
    }

    #[test]
    fn test262_positive_pass() {
        let (case, _tmp) = test262_case("assert.sameValue(1, 1);", None);
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Pass),
            "expected Pass, got: {outcome:?}"
        );
    }

    #[test]
    fn test262_positive_assertion_failure() {
        let (case, _tmp) = test262_case("assert.sameValue(1, 2);", None);
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Fail { .. }),
            "expected Fail, got: {outcome:?}"
        );
    }

    #[test]
    fn test262_positive_unexpected_error() {
        let (case, _tmp) = test262_case("undeclaredVar;", None);
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Fail { .. }),
            "expected Fail for unexpected error, got: {outcome:?}"
        );
    }

    #[test]
    fn test262_negative_matching_error() {
        let (case, _tmp) = test262_case("undeclaredVar;", Some(ExpectedError::Reference));
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Pass),
            "expected Pass for matching error class, got: {outcome:?}"
        );
    }

    #[test]
    fn test262_negative_wrong_error() {
        let (case, _tmp) = test262_case("undeclaredVar;", Some(ExpectedError::Type));
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Fail { .. }),
            "expected Fail for wrong error class, got: {outcome:?}"
        );
    }

    #[test]
    fn test262_negative_no_error() {
        let (case, _tmp) = test262_case("var x = 1;", Some(ExpectedError::Reference));
        let outcome = run_case(&case);
        assert!(
            matches!(outcome, Js262Outcome::Fail { .. }),
            "expected Fail when negative test doesn't throw, got: {outcome:?}"
        );
    }
}