ktstr 0.4.19

//! Wire-format tests for `CgroupStats`, `ScenarioStats`, and
//! `AssertResult`: round-trip + strict-schema rejection of any
//! omitted required field, with documented exceptions for the
//! `#[serde(default)]` softness on `ext_metrics` and
//! `measurements`.

use super::*;

#[test]
fn scenario_stats_serde_roundtrip() {
    let s = ScenarioStats {
        cgroups: vec![CgroupStats {
            num_workers: 4,
            num_cpus: 2,
            avg_off_cpu_pct: 50.0,
            min_off_cpu_pct: 40.0,
            max_off_cpu_pct: 60.0,
            spread: 20.0,
            max_gap_ms: 150,
            max_gap_cpu: 3,
            total_migrations: 10,
            ..Default::default()
        }],
        total_workers: 4,
        total_cpus: 2,
        total_migrations: 10,
        worst_spread: 20.0,
        worst_gap_ms: 150,
        worst_gap_cpu: 3,
        ..Default::default()
    };
    let json = serde_json::to_string(&s).unwrap();
    let s2: ScenarioStats = serde_json::from_str(&json).unwrap();
    assert_eq!(s.total_workers, s2.total_workers);
    assert_eq!(s.worst_gap_ms, s2.worst_gap_ms);
    assert_eq!(s.cgroups.len(), s2.cgroups.len());
    assert_eq!(s.cgroups[0].num_workers, s2.cgroups[0].num_workers);
}

#[test]
fn assert_result_serde_roundtrip() {
    let r = AssertResult {
        passed: false,
        skipped: false,
        details: vec!["test".into()],
        stats: Default::default(),
        measurements: std::collections::BTreeMap::new(),
    };
    let json = serde_json::to_string(&r).unwrap();
    let r2: AssertResult = serde_json::from_str(&json).unwrap();
    assert_eq!(r.passed, r2.passed);
    assert_eq!(r.details, r2.details);
}

/// Strict-schema rejection sibling for `CgroupStats`. The
/// sidecar wire format persists one
/// [`CgroupStats`](crate::assert::CgroupStats) per entry inside
/// the [`ScenarioStats::cgroups`] vec, so the same schema-
/// symmetry invariant that `ScenarioStats` enforces applies here
/// one level deep. A regression that softened a required field
/// on `CgroupStats` alone would slip past the sibling
/// `ScenarioStats` test.
///
/// The exception is `ext_metrics`, which carries
/// `#[serde(default, skip_serializing_if = "BTreeMap::is_empty")]`
/// to keep the wire minimal when unused — the sibling
/// `scenario_stats_missing_ext_metrics_tolerated_by_deserialize`
/// pattern applies to `CgroupStats` by construction (serde's
/// default tolerance applies per field, not per containing
/// type) so no dedicated CgroupStats tolerance test is needed.
#[test]
fn cgroup_stats_missing_required_field_rejected_by_deserialize() {
    const REQUIRED_FIELDS: &[&str] = &[
        "num_workers",
        "num_cpus",
        "avg_off_cpu_pct",
        "min_off_cpu_pct",
        "max_off_cpu_pct",
        "spread",
        "max_gap_ms",
        "max_gap_cpu",
        "total_migrations",
        "migration_ratio",
        "p99_wake_latency_us",
        "median_wake_latency_us",
        "wake_latency_cv",
        "total_iterations",
        "mean_run_delay_us",
        "worst_run_delay_us",
        "page_locality",
        "cross_node_migration_ratio",
    ];
    // `wake_latency_tail_ratio` and `iterations_per_worker` are
    // method-only on CgroupStats and DO NOT appear in the JSON
    // wire format; they are recomputed on read from p99/median
    // and total_iterations/num_workers respectively.

    let cg = CgroupStats::default();
    let full = match serde_json::to_value(&cg).unwrap() {
        serde_json::Value::Object(m) => m,
        other => panic!("expected object, got {other:?}"),
    };

    for field in REQUIRED_FIELDS {
        let mut obj = full.clone();
        assert!(
            obj.remove(*field).is_some(),
            "CgroupStats must emit `{field}` for its rejection \
             case to be meaningful — the field list in this test \
             has drifted from the struct definition",
        );
        let json = serde_json::Value::Object(obj).to_string();
        let err = serde_json::from_str::<CgroupStats>(&json)
            .err()
            .unwrap_or_else(|| {
                panic!("deserialize must reject CgroupStats with `{field}` removed, but succeeded",)
            });
        let msg = format!("{err}");
        assert!(
            msg.contains(field),
            "missing-field error for `{field}` must name the field; got: {msg}",
        );
    }
}

/// Strict-schema rejection: a `ScenarioStats` JSON with a
/// required scalar field omitted (here: `total_workers`) must
/// fail deserialization. `ScenarioStats` carries `Default` for
/// struct construction ergonomics, but that does NOT imply
/// `#[serde(default)]` on each field — and the sidecar schema
/// policy requires serialize/deserialize symmetry. A regression
/// that added `#[serde(default)]` to a scalar field (e.g. to
/// soften a schema migration) would make the `from_str` call
/// below succeed silently, defaulting to 0 without notifying the
/// consumer that the producer omitted data.
///
/// The exception is `ext_metrics`, which intentionally carries
/// `#[serde(default, skip_serializing_if = "BTreeMap::is_empty")]`
/// to keep the wire minimal when unused — a complementary test
/// below pins THAT tolerance so dropping it by accident also
/// trips.
#[test]
fn scenario_stats_missing_required_scalar_rejected_by_deserialize() {
    // Table-driven expansion covering EVERY required scalar field
    // instead of a single `total_workers` sentinel. Each removal
    // must produce a missing-field error naming the removed
    // field. The loop forces a pass-or-fail result per field, so
    // a regression that softens just one field (e.g. adds
    // `#[serde(default)]` to `worst_gap_cpu` alone) trips this
    // test with a field-level assertion message — the old single-
    // sentinel form would have passed silently on any field
    // other than `total_workers`.
    //
    // `ext_metrics` is intentionally NOT in this list: it carries
    // `#[serde(default, skip_serializing_if = "BTreeMap::is_empty")]`
    // and is pinned as tolerated by the sibling
    // `scenario_stats_missing_ext_metrics_tolerated_by_deserialize`
    // test. A field added with `#[serde(default)]` going forward
    // must be added to that sibling's rationale, not this list.
    const REQUIRED_FIELDS: &[&str] = &[
        "cgroups",
        "total_workers",
        "total_cpus",
        "total_migrations",
        "worst_spread",
        "worst_gap_ms",
        "worst_gap_cpu",
        "worst_migration_ratio",
        "worst_p99_wake_latency_us",
        "worst_median_wake_latency_us",
        "worst_wake_latency_cv",
        "total_iterations",
        "worst_mean_run_delay_us",
        "worst_run_delay_us",
        "worst_page_locality",
        "worst_cross_node_migration_ratio",
        "worst_wake_latency_tail_ratio",
        "worst_iterations_per_worker",
    ];

    let s = ScenarioStats::default();
    let full = match serde_json::to_value(&s).unwrap() {
        serde_json::Value::Object(m) => m,
        other => panic!("expected object, got {other:?}"),
    };

    for field in REQUIRED_FIELDS {
        let mut obj = full.clone();
        assert!(
            obj.remove(*field).is_some(),
            "ScenarioStats must emit `{field}` for its rejection case to be meaningful — \
             the field list in this test has drifted from the struct definition",
        );
        let json = serde_json::Value::Object(obj).to_string();
        let err = serde_json::from_str::<ScenarioStats>(&json)
            .err()
            .unwrap_or_else(|| {
                panic!(
                    "deserialize must reject ScenarioStats with `{field}` removed, but succeeded",
                )
            });
        let msg = format!("{err}");
        assert!(
            msg.contains(field),
            "missing-field error for `{field}` must name the field; got: {msg}",
        );
    }
}

/// Positive control for the `ext_metrics` exemption: omitting
/// `ext_metrics` from the wire is accepted (serde defaults it to
/// an empty `BTreeMap`). This is the ONE deliberate softness in
/// `ScenarioStats`'s schema — pinned here so a future sweep that
/// removes the `#[serde(default)]` attribute alongside other
/// hardening trips this test and forces a conscious decision.
#[test]
fn scenario_stats_missing_ext_metrics_tolerated_by_deserialize() {
    let s = ScenarioStats::default();
    let mut obj = match serde_json::to_value(&s).unwrap() {
        serde_json::Value::Object(m) => m,
        other => panic!("expected object, got {other:?}"),
    };
    // `skip_serializing_if = "BTreeMap::is_empty"` keeps ext_metrics
    // off the wire when empty — remove it if present, then assert
    // the absence round-trips without error.
    obj.remove("ext_metrics");
    let without_ext_metrics = serde_json::Value::Object(obj).to_string();
    let parsed: ScenarioStats = serde_json::from_str(&without_ext_metrics)
        .expect("deserialize must tolerate missing ext_metrics (the sole exempt field)");
    assert!(
        parsed.ext_metrics.is_empty(),
        "missing ext_metrics must default to empty, got {:?}",
        parsed.ext_metrics,
    );
}

/// Strict-schema rejection: an `AssertResult` JSON with a
/// required field omitted (here: `passed`) must fail
/// deserialization. `AssertResult` has NO `Default` derive and no
/// `#[serde(default)]` — every field is required on the wire.
/// Pinned so a regression that softens any of passed / skipped /
/// details / stats trips this test.
#[test]
fn assert_result_missing_required_field_rejected_by_deserialize() {
    // All four `AssertResult` fields are wire-required (the struct
    // has no `Default` derive and no `#[serde(default)]` on any
    // field). Loop over each; each removal must fail deserialize
    // with a missing-field error naming the removed field.
    const REQUIRED_FIELDS: &[&str] = &["passed", "skipped", "details", "stats"];
    // `measurements` is intentionally NOT in REQUIRED_FIELDS — it
    // carries `#[serde(default, skip_serializing_if = ...)]` so old
    // sidecars without the key deserialize cleanly with an empty
    // map. The companion test
    // `assert_result_missing_measurements_tolerated_by_deserialize`
    // pins THAT tolerance.

    let r = AssertResult {
        passed: false,
        skipped: false,
        details: vec!["detail".into()],
        stats: ScenarioStats::default(),
        measurements: std::collections::BTreeMap::new(),
    };
    let full = match serde_json::to_value(&r).unwrap() {
        serde_json::Value::Object(m) => m,
        other => panic!("expected object, got {other:?}"),
    };

    for field in REQUIRED_FIELDS {
        let mut obj = full.clone();
        assert!(
            obj.remove(*field).is_some(),
            "AssertResult must emit `{field}` for its rejection case to be meaningful",
        );
        let json = serde_json::Value::Object(obj).to_string();
        let err = serde_json::from_str::<AssertResult>(&json).err().unwrap_or_else(
            || panic!(
                "deserialize must reject AssertResult with `{field}` removed, but succeeded",
            ),
        );
        let msg = format!("{err}");
        assert!(
            msg.contains(field),
            "missing-field error for `{field}` must name the field; got: {msg}",
        );
    }
}

/// Old sidecars without the `measurements` key deserialize cleanly
/// with an empty map — the field carries `#[serde(default)]`.
#[test]
fn assert_result_missing_measurements_tolerated_by_deserialize() {
    let json = r#"{"passed":true,"skipped":false,"details":[],"stats":{
        "cgroups":[],"total_workers":0,"total_cpus":0,"total_migrations":0,
        "worst_spread":0,"worst_gap_ms":0,"worst_gap_cpu":0,
        "worst_migration_ratio":0,"worst_p99_wake_latency_us":0,
        "worst_median_wake_latency_us":0,"worst_wake_latency_cv":0,
        "total_iterations":0,"worst_mean_run_delay_us":0,
        "worst_run_delay_us":0,"worst_page_locality":0,
        "worst_cross_node_migration_ratio":0,
        "worst_wake_latency_tail_ratio":0,"worst_iterations_per_worker":0
    }}"#;
    let r: AssertResult =
        serde_json::from_str(json).expect("missing-measurements must deserialize cleanly");
    assert!(r.measurements.is_empty());
}