Files
trueskill-tt/tests/api_shape.rs
T
logaritmiskandClaude Opus 5 c12bc830a5 feat!: name the unknown key, expose tail probabilities, flag short fits
Three issues from two downstream consumers, all small, all sharing a
theme: the crate had the information and would not hand it over.

#44 — `UnknownKey { team: 0, member: 0 }` did not say which key. A
consumer upgrading 0.1.2 -> 0.4.1 had every one of 5591 predictions
return this error, fell back to a neutral 0.5, and lost its entire
metadata model for a day. Nothing crashed and nothing logged; it was
found by sweeping an unrelated parameter and noticing the output did not
move. The 0.4.0 change that made unknown keys an error was right — the
error was just too anonymous to act on. It now carries the key's `Debug`
rendering, and its `Display` says what to do about it. The precondition
is documented on every prediction entry point, which the reporter said
would alone have saved the day.

#43 — `cdf` was `pub(crate)`, so a consumer asking "is this competitor
below the cutoff" approximated it with a `mu + z * sigma` band and had no
way to say what confidence any `z` bought. Adds
`Gaussian::probability_below` / `probability_above`. The second is
separate on purpose: `1 - cdf` collapses to exactly zero past ~8.3
sigma, and a stopping rule is evaluated precisely there. Both route
through the survival function added in 0.4.1, so this is visibility
rather than new numerics.

#50 — `ConvergenceReport` was not `#[must_use]`, so the one signal that
a fit stopped short was trivially discarded. It now is, and that
immediately found 78 sites doing exactly that — including this crate's
own ATP example, which was capped at 10 sweeps when the history needs
30. The example now reads the report and says so.

`ITERATIONS = 30` is documented as the floor it is, with the three
measurements to hand: 400 events over 100 competitors already stops
there at ~7e-3 against a 1e-6 tolerance, the ATP example needs 30 at a
much looser one, and a consumer's 2000-node model needs 76 to 161.

BREAKING CHANGE: `InferenceError::UnknownKey` gains a `key` field, and
the prediction methods now require `K: Debug` in order to fill it.

Closes #43, #50. Refs #44 — its third ask, an opt-in `UnknownKeys::Skip`
mode, is a live API question and deliberately not answered here.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
2026-09-07 23:41:03 +02:00

297 lines
7.8 KiB
Rust

//! Tests for the new T2 public API surface: typed add_events(iter) and the
//! fluent event builder (added in Task 16).
use smallvec::smallvec;
use trueskill_tt::{ConstantDrift, ConvergenceOptions, Event, History, Member, Outcome, Team};
#[test]
fn add_events_bulk_via_iter() {
let mut h = History::builder()
.mu(0.0)
.sigma(2.0)
.beta(1.0)
.p_draw(0.0)
.drift(ConstantDrift(0.0))
.convergence(ConvergenceOptions {
max_iter: 30,
epsilon: 1e-6,
alpha: 1.0,
})
.build();
let events: Vec<Event<i64, &'static str>> = vec![
Event {
time: 1,
teams: smallvec![
Team::with_members([Member::new("a")]),
Team::with_members([Member::new("b")]),
],
outcome: Outcome::winner(0, 2),
},
Event {
time: 2,
teams: smallvec![
Team::with_members([Member::new("b")]),
Team::with_members([Member::new("c")]),
],
outcome: Outcome::winner(0, 2),
},
];
h.add_events(events).unwrap();
let report = h.converge().unwrap();
assert!(report.converged);
assert!(h.lookup(&"a").is_some());
assert!(h.lookup(&"b").is_some());
assert!(h.lookup(&"c").is_some());
}
#[test]
fn add_events_draw() {
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.25)
.drift(ConstantDrift(25.0 / 300.0))
.build();
let events: Vec<Event<i64, &'static str>> = vec![Event {
time: 1,
teams: smallvec![
Team::with_members([Member::new("alice")]),
Team::with_members([Member::new("bob")]),
],
outcome: Outcome::draw(2),
}];
h.add_events(events).unwrap();
let _ = h.converge().unwrap();
}
#[test]
fn add_events_rejects_mismatched_outcome_ranks() {
use trueskill_tt::InferenceError;
let mut h: History = History::builder().build();
let events: Vec<Event<i64, &'static str>> = vec![Event {
time: 1,
teams: smallvec![
Team::with_members([Member::new("a")]),
Team::with_members([Member::new("b")]),
],
outcome: Outcome::ranking([0, 1, 2]), // 3 ranks but 2 teams
}];
let err = h.add_events(events).unwrap_err();
assert!(matches!(err, InferenceError::MismatchedShape { .. }));
}
#[test]
fn fluent_event_builder_basic() {
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.0)
.build();
h.event(1)
.team(["alice", "bob"])
.weights([1.0, 0.7])
.team(["carol"])
.ranking([1, 0])
.commit()
.unwrap();
let report = h.converge().unwrap();
assert!(report.converged);
assert!(h.lookup(&"alice").is_some());
assert!(h.lookup(&"bob").is_some());
assert!(h.lookup(&"carol").is_some());
}
#[test]
fn fluent_event_builder_winner_convenience() {
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.0)
.build();
h.event(1)
.team(["alice"])
.team(["bob"])
.winner(0)
.commit()
.unwrap();
let _ = h.converge().unwrap();
}
#[test]
fn fluent_event_builder_draw() {
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.25)
.build();
h.event(1)
.team(["alice"])
.team(["bob"])
.draw()
.commit()
.unwrap();
let _ = h.converge().unwrap();
}
#[test]
fn current_skill_and_learning_curve() {
use trueskill_tt::History;
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.0)
.build();
h.record_winner(&"a", &"b", 1).unwrap();
h.record_winner(&"a", &"b", 2).unwrap();
let _ = h.converge().unwrap();
let a = h.current_skill(&"a").unwrap();
assert!(a.mu() > 25.0);
let b = h.current_skill(&"b").unwrap();
assert!(b.mu() < 25.0);
let a_curve = h.learning_curve(&"a");
assert_eq!(a_curve.len(), 2);
assert_eq!(a_curve[0].0, 1);
assert_eq!(a_curve[1].0, 2);
let all = h.learning_curves();
assert_eq!(all.len(), 2);
assert!(all.contains_key("a"));
assert!(all.contains_key("b"));
}
#[test]
fn log_evidence_total_vs_subset() {
use trueskill_tt::{ConstantDrift, History};
let mut h = History::builder()
.mu(0.0)
.sigma(6.0)
.beta(1.0)
.p_draw(0.0)
.drift(ConstantDrift(0.0))
.build();
h.record_winner(&"a", &"b", 1).unwrap();
h.record_winner(&"b", &"a", 2).unwrap();
let total = h.log_evidence();
let a_only = h.log_evidence_for(&[&"a"]);
assert!(total.is_finite());
assert!(a_only.is_finite());
}
#[test]
fn predict_quality_two_teams() {
use trueskill_tt::History;
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.0)
.build();
h.record_winner(&"a", &"b", 1).unwrap();
let _ = h.converge().unwrap();
let q = h.predict_quality(&[&[&"a"], &[&"b"]]).unwrap();
assert!(q > 0.0 && q <= 1.0);
}
#[test]
fn predict_outcome_two_teams_sums_to_one() {
use trueskill_tt::History;
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.p_draw(0.0)
.build();
h.record_winner(&"a", &"b", 1).unwrap();
let _ = h.converge().unwrap();
let p = h.predict_outcome(&[&[&"a"], &[&"b"]]).unwrap();
let wins = p.win_probabilities();
assert_eq!(wins.len(), 2);
// With p_draw == 0 there is no draw outcome, so the two win
// probabilities are the whole space.
assert!((p.total() - 1.0).abs() < 1e-9, "total = {}", p.total());
assert!((wins[0] + wins[1] - 1.0).abs() < 1e-9);
assert!(wins[0] > wins[1]);
}
#[test]
fn fluent_event_builder_scores() {
use trueskill_tt::ConstantDrift;
let mut h = History::builder()
.mu(25.0)
.sigma(25.0 / 3.0)
.beta(25.0 / 6.0)
.drift(ConstantDrift(0.0))
.build();
h.event(1)
.team(["alice"])
.team(["bob"])
.scores([12.0, 4.0])
.commit()
.unwrap();
let _ = h.converge().unwrap();
let a = h.current_skill(&"alice").unwrap();
let b = h.current_skill(&"bob").unwrap();
assert!(a.mu() > b.mu());
}
/// Every field of `ConvergenceReport` must carry real information.
///
/// `slices_skipped` was public, hardcoded to `0`, and reported a plausible
/// value for a feature that never existed — the same shape as the inert
/// `online` flag in #19. It was removed in #33. This pins the remaining fields
/// so the next always-constant member has to survive an assertion rather than
/// just a reviewer's attention.
#[test]
fn every_convergence_report_field_is_populated() {
let mut h = History::builder().build();
for time in 1..=6i64 {
h.record_winner(&"a", &"b", time).unwrap();
}
let report = h.converge().unwrap();
assert!(
report.iterations > 0,
"iterations is zero on a real converge"
);
assert!(report.converged, "fixture must converge");
assert!(
report.final_step.0.is_finite() && report.final_step.1.is_finite(),
"final_step is not finite: {:?}",
report.final_step
);
assert!(
report.log_evidence.is_finite() && report.log_evidence < 0.0,
"log_evidence is not a finite negative log probability: {}",
report.log_evidence
);
assert_eq!(
report.per_iteration_time.len(),
report.iterations,
"per_iteration_time must carry one duration per iteration"
);
}