decision/crates/ld-server/tests/inertia.rs

//! Inertia in five levels (ADR 0007): the levels and the scale served, the
//! usual participation of a group, the change of inertia voted at the level
//! of its article, the migration of the four words of before, and the
//! amendment that raises E1 and E2 to level 4 in an existing base.

use axum::body::Body;
use axum::http::{Request, StatusCode, header};
use http_body_util::BodyExt;
use ld_engine::inertia::{InertiaLevel, Scale, gradient};
use ld_engine::threshold::required_ratio;
use ld_server::{AppState, CSRF_HEADER, CSRF_VALUE, Config, app, open_db, seed};
use serde_json::{Value, json};
use sqlx::SqlitePool;
use std::borrow::Cow;
use tower::ServiceExt;

struct Client {
    router: axum::Router,
    cookie: Option<String>,
}

impl Client {
    fn of(state: &AppState) -> Self {
        Self { router: app(state.clone()), cookie: None }
    }

    async fn new() -> (Self, AppState) {
        let db = open_db("sqlite::memory:").await.expect("db");
        let state = AppState::new(Config::for_tests(), db).await.expect("state");
        seed::ensure(&state).await.expect("seed");
        (Self::of(&state), state)
    }

    fn other(&self) -> Self {
        Self { router: self.router.clone(), cookie: None }
    }

    async fn call(&mut self, method: &str, uri: &str, body: Option<Value>) -> (StatusCode, Value) {
        let mut req = Request::builder().method(method).uri(uri).header(CSRF_HEADER, CSRF_VALUE);
        if let Some(c) = &self.cookie {
            req = req.header(header::COOKIE, c);
        }
        let req = match body {
            Some(b) => req.header(header::CONTENT_TYPE, "application/json").body(Body::from(b.to_string())),
            None => req.body(Body::empty()),
        }
        .expect("request");
        let res = self.router.clone().oneshot(req).await.expect("response");
        let status = res.status();
        if let Some(set) = res.headers().get(header::SET_COOKIE) {
            let raw = set.to_str().expect("cookie").split(';').next().unwrap_or_default().to_owned();
            if raw.starts_with("ld_session=") {
                self.cookie = Some(raw);
            }
        }
        let bytes = res.into_body().collect().await.expect("body").to_bytes();
        (status, serde_json::from_slice(&bytes).unwrap_or(Value::Null))
    }

    async fn get(&mut self, uri: &str) -> Value {
        let (s, v) = self.call("GET", uri, None).await;
        assert_eq!(s, StatusCode::OK, "{uri}: {v}");
        v
    }

    async fn login(&mut self, name: &str) {
        let (s, v) = self.call("POST", "/api/auth/dev", Some(json!({ "name": name, "admin": false }))).await;
        assert_eq!(s, StatusCode::OK, "{v}");
    }

    async fn vote(&mut self, proposal: &str, choice: &str) -> Value {
        let (s, v) =
            self.call("POST", &format!("/api/proposals/{proposal}/vote"), Some(json!({ "choice": choice }))).await;
        assert_eq!(s, StatusCode::OK, "{v}");
        v
    }

    async fn doc(&mut self, group: &str) -> Value {
        let g = self.get(&format!("/api/groups/{group}")).await;
        let id = g["docs"][0]["id"].as_str().expect("doc").to_owned();
        self.get(&format!("/api/docs/{id}")).await
    }
}

fn unit<'a>(doc: &'a Value, code: &str) -> &'a Value {
    doc["units"].as_array().expect("units").iter().find(|u| u["code"] == code).expect("unit")
}

fn level(k: u8) -> InertiaLevel {
    InertiaLevel::new(k).expect("1 to 5")
}

fn numbers(levels: &Value, key: &str) -> Vec<f64> {
    levels.as_array().expect("levels").iter().map(|l| l[key].as_f64().expect(key)).collect()
}

#[tokio::test]
async fn the_five_levels_and_the_scale_are_served() {
    let (mut c, _) = Client::new().await;
    c.login("Chiara").await;
    let doc = c.doc("monnaie-libre").await;
    // 3 everywhere, 4 for the two structural commitments.
    let raised: Vec<&str> = doc["units"]
        .as_array()
        .expect("units")
        .iter()
        .filter(|u| u["inertia"] != 3)
        .map(|u| u["code"].as_str().expect("code"))
        .collect();
    assert_eq!(raised, ["E1", "E2"]);
    assert!(unit(&doc, "E1")["inertia"] == 4 && unit(&doc, "E2")["inertia"] == 4);

    // No vote yet: the reference, 2C/W = 100 voters out of 5745.
    let p = &doc["doc"]["participation"];
    assert_eq!(
        (p["source"].as_str(), p["sample"].as_u64(), p["voters"].as_u64()),
        (Some("reference"), Some(0), Some(100))
    );
    assert_eq!(
        (p["minSample"].as_u64(), p["windowDays"].as_u64(), p["everyHours"].as_u64()),
        (Some(5), Some(365), Some(24))
    );
    let ratio = p["ratio"].as_f64().expect("ratio");
    assert!((ratio - 100.0 / 5745.0).abs() < 1e-12);

    let levels = &doc["levels"];
    assert_eq!(numbers(levels, "level"), [1.0, 2.0, 3.0, 4.0, 5.0]);
    assert_eq!(numbers(levels, "majorityPct"), [50.0, 50.0, 55.0, 60.0, 66.0]);
    assert_eq!(numbers(levels, "sharePct"), [60.0, 67.0, 75.0, 83.0, 90.0]);
    let scale = Scale { electorate: 5745, floor: 50.0, participation: ratio };
    for (l, k) in levels.as_array().expect("levels").iter().zip(InertiaLevel::ALL) {
        assert!((l["gradient"].as_f64().expect("G") - gradient(k, ratio)).abs() < 1e-12);
        // At the usual participation, C plus s_k of the votes beyond C.
        assert_eq!(l["cast"], 100);
        assert_eq!(l["required"].as_u64(), Some(u64::from(scale.required(100, k).expect("valid"))));
        let at_usual = 50.0 + k.share_pct() / 100.0 * 50.0;
        assert_eq!(l["required"].as_f64(), Some(at_usual.ceil()));
    }

    // A version: the five levels at its own participation, and the level it is voted at.
    let e1 = unit(&doc, "E1")["inForce"]["id"].as_str().expect("e1").to_owned();
    let d = c.get(&format!("/api/proposals/{e1}")).await;
    assert_eq!(d["proposal"]["votedAtInertia"], 4);
    assert_eq!(numbers(&d["levels"], "cast"), [0.0; 5]);
    assert_eq!(numbers(&d["levels"], "required"), [50.0; 5], "nothing passes under C");
    assert_eq!(d["participation"]["source"], "reference");
    assert_eq!(d["electorateSource"], "wot");
}

#[tokio::test]
async fn a_change_of_inertia_is_voted_at_the_level_of_its_article_and_journaled() {
    let (mut a, state) = Client::new().await;
    a.login("Yvv").await;
    let mut b = a.other();
    b.login("Chiara").await;
    let doc = a.doc("essai").await;
    let e2 = unit(&doc, "E2")["id"].as_str().expect("e2").to_owned();
    let to = |t: Value| json!({ "target": t });
    for bad in [json!(0), json!(6), json!("haute"), json!(null)] {
        let (s, v) = a.call("POST", &format!("/api/units/{e2}/inertia"), Some(to(bad.clone()))).await;
        assert_eq!((s, v["error"].as_str()), (StatusCode::BAD_REQUEST, Some("inertia")), "{bad}");
    }
    let (s, v) = a.call("POST", &format!("/api/units/{e2}/inertia"), Some(to(json!(4)))).await;
    assert_eq!((s, v["error"].as_str()), (StatusCode::BAD_REQUEST, Some("same_inertia")));
    let (s, v) = a.call("POST", &format!("/api/units/{e2}/inertia"), Some(to(json!(1)))).await;
    assert_eq!(s, StatusCode::OK, "{v}");
    let p = v["id"].as_str().expect("id").to_owned();
    let d = a.get(&format!("/api/proposals/{p}")).await;
    assert_eq!((d["proposal"]["inertiaTarget"].as_u64(), d["proposal"]["votedAtInertia"].as_u64()), (Some(1), Some(4)));
    // W(essai) = 2: both vote for, the article goes to level 1.
    a.vote(&p, "for").await;
    let v = b.vote(&p, "for").await;
    assert_eq!(v["entered"][0]["kind"], "inertia");
    let doc = a.doc("essai").await;
    let e2u = unit(&doc, "E2");
    assert_eq!(e2u["inertia"], 1);
    let changes = e2u["inertiaChanges"].as_array().expect("changes");
    assert_eq!(changes.len(), 1);
    assert_eq!(
        (changes[0]["from"].as_u64(), changes[0]["to"].as_u64(), changes[0]["cause"].as_str()),
        (Some(4), Some(1), Some("vote"))
    );
    // The adoption keeps the level it was judged at, and the scale.
    let params: String = sqlx::query_scalar("SELECT params FROM adoptions WHERE proposal_id = ?")
        .bind(&p)
        .fetch_one(&state.db)
        .await
        .expect("adoption");
    let params: Value = serde_json::from_str(&params).expect("json");
    assert_eq!(
        (params["level"].as_u64(), params["majority_pct"].as_f64(), params["share_pct"].as_f64()),
        (Some(4), Some(60.0), Some(83.0))
    );
    assert_eq!(
        (params["participation"].as_f64(), params["participation_source"].as_str()),
        (Some(0.5), Some("reference"))
    );
    assert!(params["gradient"].as_f64().is_some_and(|g| (g - gradient(level(4), 0.5)).abs() < 1e-12));
}

#[tokio::test]
async fn the_usual_participation_is_the_median_of_five_voted_proposals() {
    let (mut first, state) = Client::new().await;
    // Ten people, all members of the test group: W = 10, C = 1.
    let mut people = Vec::new();
    for name in ["P1", "P2", "P3", "P4", "P5", "P6", "P7", "P8", "P9", "P10"] {
        let mut c = first.other();
        c.login(name).await;
        people.push(c);
    }
    first.login("P1").await;
    let doc = first.doc("essai").await;
    let open: Vec<String> = ["I2", "T1", "E4", "E5", "E6"]
        .iter()
        .map(|code| unit(&doc, code)["proposals"][0]["id"].as_str().expect("open").to_owned())
        .collect();
    // 1, 2, 3, 3 and 4 voters (against: nothing enters into force, the count is what matters).
    for (p, n) in open.iter().zip([1, 2, 3, 3, 4]) {
        for c in people.iter_mut().take(n) {
            c.vote(p, "against").await;
        }
    }
    // Measured once a day, not at each vote: until then, the reference.
    let doc = first.doc("essai").await;
    assert_eq!(doc["doc"]["participation"]["source"], "reference");
    assert_eq!(doc["doc"]["electorate"], 10);

    let measured = ld_server::participation::refresh(&state, false).await.expect("refresh");
    assert!(measured.contains(&"essai".to_owned()));
    let doc = first.doc("essai").await;
    let p = &doc["doc"]["participation"];
    assert_eq!(
        (p["source"].as_str(), p["sample"].as_u64(), p["median"].as_f64()),
        (Some("median"), Some(5), Some(3.0))
    );
    assert_eq!((p["ratio"].as_f64(), p["voters"].as_u64(), p["bounded"].as_bool()), (Some(0.3), Some(3), Some(false)));
    assert!(p["measuredAt"].is_string());
    for (l, k) in doc["levels"].as_array().expect("levels").iter().zip(InertiaLevel::ALL) {
        assert!((l["gradient"].as_f64().expect("G") - gradient(k, 0.3)).abs() < 1e-12);
    }
    // Thresholds follow: the proposal with 4 voters is judged on this scale.
    let d = first.get(&format!("/api/proposals/{}", open[4])).await;
    let scale = Scale { electorate: 10, floor: 1.0, participation: 0.3 };
    let ratio = d["proposal"]["evaluation"]["requiredRatio"].as_f64().expect("ratio");
    assert!((ratio - required_ratio(10, 4, &scale.params(level(3)))).abs() < 1e-12);

    // A new vote does not move it within the day…
    people[4].vote(&open[0], "against").await;
    assert!(ld_server::participation::refresh(&state, false).await.expect("refresh").is_empty());
    assert_eq!(first.doc("essai").await["doc"]["participation"]["median"], 3.0);
    // …the next measure sees it: 2, 2, 3, 3, 4.
    ld_server::participation::refresh(&state, true).await.expect("refresh");
    assert_eq!(first.doc("essai").await["doc"]["participation"]["median"], 3.0);

    // A proposal last voted on more than a year ago leaves the sample: four are too few.
    sqlx::query("UPDATE votes SET cast_at = '2025-01-01T00:00:00Z' WHERE proposal_id = ?")
        .bind(&open[2])
        .execute(&state.db)
        .await
        .expect("age");
    ld_server::participation::refresh(&state, true).await.expect("refresh");
    let p = first.doc("essai").await["doc"]["participation"].clone();
    assert_eq!(
        (p["source"].as_str(), p["sample"].as_u64(), p["median"].as_f64()),
        (Some("reference"), Some(4), Some(2.5))
    );
    // The reference of the test group: 2C/W = 20 %.
    assert_eq!(p["ratio"].as_f64(), Some(0.2));
    // Monnaie libre is measured apart, from its own votes (none).
    let ml = first.doc("monnaie-libre").await;
    assert_eq!(
        (ml["doc"]["participation"]["sample"].as_u64(), ml["doc"]["participation"]["source"].as_str()),
        (Some(0), Some("reference"))
    );
}

#[tokio::test]
async fn a_withdrawn_proposal_leaves_the_usual_participation() {
    // Relecture of a576b68: withdrawn proposals vanish from the document and their
    // votes can no longer be taken back, so they must not weigh on the median.
    let (mut first, state) = Client::new().await;
    let mut people = Vec::new();
    for name in ["W1", "W2", "W3", "W4"] {
        let mut c = first.other();
        c.login(name).await;
        people.push(c);
    }
    first.login("W1").await;
    let doc = first.doc("essai").await;
    let open: Vec<String> = ["I2", "T1", "E4", "E5", "E6"]
        .iter()
        .map(|code| unit(&doc, code)["proposals"][0]["id"].as_str().expect("open").to_owned())
        .collect();
    for p in &open {
        for c in people.iter_mut().take(2) {
            c.vote(p, "against").await;
        }
    }
    ld_server::participation::refresh(&state, true).await.expect("refresh");
    let p = first.doc("essai").await["doc"]["participation"].clone();
    assert_eq!((p["source"].as_str(), p["sample"].as_u64()), (Some("median"), Some(5)));

    sqlx::query("UPDATE proposals SET status = 'withdrawn' WHERE id = ?")
        .bind(&open[0])
        .execute(&state.db)
        .await
        .expect("withdraw");
    ld_server::participation::refresh(&state, true).await.expect("refresh");
    let p = first.doc("essai").await["doc"]["participation"].clone();
    assert_eq!((p["source"].as_str(), p["sample"].as_u64()), (Some("reference"), Some(4)));
}

// ---------------------------------------------------------------------------
// The base as production holds it on 2026-10-30, then the new version
// ---------------------------------------------------------------------------

/// Migrations up to 0004: the schema production runs before this version.
async fn base_before_levels(tag: &str) -> (SqlitePool, AppState) {
    use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
    use std::str::FromStr;
    let options = SqliteConnectOptions::from_str("sqlite::memory:").expect("url").foreign_keys(true);
    let pool = SqlitePoolOptions::new().max_connections(1).connect_with(options).await.expect("db");
    let mut before = sqlx::migrate!("./migrations");
    before.migrations = Cow::Owned(before.migrations.iter().filter(|m| m.version <= 4).cloned().collect());
    before.run(&pool).await.expect("migrations 1 to 4");
    let mut cfg = Config::for_tests();
    cfg.data_dir = std::env::temp_dir().join(format!("ld-levels-{tag}-{}", std::process::id()));
    let state = AppState::new(cfg, pool.clone()).await.expect("state");
    seed::documents(&state).await.expect("documents");
    // The words of the time: every article `standard`.
    sqlx::query("UPDATE units SET inertia = 'standard'").execute(&pool).await.expect("words");
    (pool, state)
}

/// The new version starts: migration 0005, then the seed and its amendments.
async fn start_new_version(pool: &SqlitePool) -> AppState {
    let mut all = sqlx::migrate!("./migrations");
    all.set_ignore_missing(true);
    all.run(pool).await.expect("migrations");
    restart(pool).await
}

async fn restart(pool: &SqlitePool) -> AppState {
    let state = AppState::new(Config::for_tests(), pool.clone()).await.expect("state");
    seed::ensure(&state).await.expect("seed");
    state
}

async fn unit_id(pool: &SqlitePool, group: &str, code: &str) -> String {
    sqlx::query_scalar(
        "SELECT u.id FROM units u JOIN documents d ON d.id = u.doc_id WHERE d.group_slug = ? AND u.code = ?",
    )
    .bind(group)
    .bind(code)
    .fetch_one(pool)
    .await
    .expect("unit")
}

/// An open change of inertia written as production holds it (a word, no vote).
async fn legacy_inertia_proposal(pool: &SqlitePool, unit: &str, word: &str) -> String {
    let id = format!("legacy-{unit}-{word}");
    sqlx::query(
        "INSERT INTO proposals (id, unit_id, kind, inertia_target, title, body, status, origin, author_id, revision,
           created_at, updated_at, submitted_at)
         VALUES (?, ?, 'inertia', ?, ?, '', 'open', 'member', NULL, 1, '2026-10-29T21:54:00Z', '2026-10-29T21:54:00Z',
           '2026-10-29T21:54:00Z')",
    )
    .bind(&id)
    .bind(unit)
    .bind(word)
    .bind(format!("inertia:{word}"))
    .execute(pool)
    .await
    .expect("proposal");
    id
}

type Decision = (String, String, String, Option<String>);

async fn inertia_decisions(pool: &SqlitePool) -> Vec<Decision> {
    sqlx::query_as(
        "SELECT d.group_slug, a.unit_code, a.outcome, a.reason FROM inertia_amendments a
           JOIN documents d ON d.id = a.doc_id ORDER BY d.group_slug, a.unit_code",
    )
    .fetch_all(pool)
    .await
    .expect("decisions")
}

fn decided(rows: &[Decision]) -> Vec<(&str, &str, &str, Option<&str>)> {
    rows.iter().map(|(g, u, o, r)| (g.as_str(), u.as_str(), o.as_str(), r.as_deref())).collect()
}

#[tokio::test]
async fn a_new_base_starts_with_e1_and_e2_at_level_4() {
    let (_, state) = Client::new().await;
    assert_eq!(
        decided(&inertia_decisions(&state.db).await),
        [
            ("essai", "E1", "present", None),
            ("essai", "E2", "present", None),
            ("monnaie-libre", "E1", "present", None),
            ("monnaie-libre", "E2", "present", None),
        ]
    );
    let changes: i64 =
        sqlx::query_scalar("SELECT COUNT(*) FROM inertia_changes").fetch_one(&state.db).await.expect("n");
    assert_eq!(changes, 0, "born at 4: nothing changed");
}

#[tokio::test]
async fn the_migration_turns_the_four_words_into_levels_and_keeps_them() {
    let (pool, _) = base_before_levels("migration").await;
    let i1 = unit_id(&pool, "monnaie-libre", "I1").await;
    let e3 = unit_id(&pool, "monnaie-libre", "E3").await;
    for (unit, word) in [(&i1, "low"), (&e3, "high")] {
        sqlx::query("UPDATE units SET inertia = ? WHERE id = ?")
            .bind(word)
            .bind(unit)
            .execute(&pool)
            .await
            .expect("word");
    }
    let p = legacy_inertia_proposal(&pool, &e3, "max").await;
    // An adoption of before: its params are the letters it was judged by.
    let old_params = r#"{"majority_pct":50.0,"gradient":0.2,"base":0.1,"constant":50.0}"#;
    sqlx::query(
        "INSERT INTO adoptions (proposal_id, unit_id, doc_id, kind, votes_for, votes_against, electorate, required, params, at)
         SELECT 'past', ?, doc_id, 'text', 60, 0, 7224, 58, ?, '2026-10-25T00:00:00Z' FROM units WHERE id = ?",
    )
    .bind(&e3)
    .bind(old_params)
    .bind(&e3)
    .execute(&pool)
    .await
    .expect("adoption");

    let mut all = sqlx::migrate!("./migrations");
    all.set_ignore_missing(true);
    all.run(&pool).await.expect("migration 0005");

    let words: Vec<(String, String, Option<String>)> =
        sqlx::query_as("SELECT code, inertia, inertia_legacy FROM units WHERE doc_id = (SELECT doc_id FROM units WHERE id = ?) AND code IN ('I1', 'E1', 'E3') ORDER BY code")
            .bind(&i1)
            .fetch_all(&pool)
            .await
            .expect("units");
    assert_eq!(
        words,
        [
            ("E1".into(), "3".into(), Some("standard".into())),
            ("E3".into(), "4".into(), Some("high".into())),
            ("I1".into(), "2".into(), Some("low".into())),
        ]
    );
    let target: (Option<String>, Option<String>) =
        sqlx::query_as("SELECT inertia_target, inertia_target_legacy FROM proposals WHERE id = ?")
            .bind(&p)
            .fetch_one(&pool)
            .await
            .expect("proposal");
    assert_eq!(target, (Some("5".into()), Some("max".into())));
    let kept: String = sqlx::query_scalar("SELECT params FROM adoptions WHERE proposal_id = 'past'")
        .fetch_one(&pool)
        .await
        .expect("params");
    assert_eq!(kept, old_params, "the history is never rewritten");
}

/// Production on 2026-10-30 (orch): every article `standard`, no vote, and two open
/// changes of inertia at zero votes, I1 → max and E1 → max.
#[tokio::test]
async fn e1_and_e2_go_to_level_4_once_and_an_open_change_stays_open_voted_at_4() {
    let (pool, _) = base_before_levels("production").await;
    let mut proposals = Vec::new();
    for group in ["monnaie-libre", "essai"] {
        for code in ["I1", "E1"] {
            let u = unit_id(&pool, group, code).await;
            proposals.push((group, code, legacy_inertia_proposal(&pool, &u, "max").await));
        }
    }
    let state = start_new_version(&pool).await;
    let first = inertia_decisions(&pool).await;
    assert_eq!(
        decided(&first),
        [
            ("essai", "E1", "applied", None),
            ("essai", "E2", "applied", None),
            ("monnaie-libre", "E1", "applied", None),
            ("monnaie-libre", "E2", "applied", None),
        ]
    );
    let mut c = Client::of(&state);
    c.login("Yvv").await;
    for group in ["monnaie-libre", "essai"] {
        let doc = c.doc(group).await;
        let levels: Vec<(&str, u64)> = ["I1", "E1", "E2", "E3"]
            .iter()
            .map(|code| (*code, unit(&doc, code)["inertia"].as_u64().expect("level")))
            .collect();
        assert_eq!(levels, [("I1", 3), ("E1", 4), ("E2", 4), ("E3", 3)], "{group}");
        // The article says so.
        let changes = unit(&doc, "E1")["inertiaChanges"].as_array().expect("changes").clone();
        assert_eq!(changes.len(), 1);
        assert_eq!(
            (changes[0]["from"].as_u64(), changes[0]["to"].as_u64(), changes[0]["cause"].as_str()),
            (Some(3), Some(4), Some("amendment"))
        );
    }
    // The open changes stay open, their target read as 5, voted at the article's level.
    for (group, code, id) in &proposals {
        let d = c.get(&format!("/api/proposals/{id}")).await;
        assert_eq!(d["proposal"]["status"], "open", "{group} {code}");
        assert_eq!(d["proposal"]["inertiaTarget"], 5, "{group} {code}");
        let at = if *code == "E1" { 4 } else { 3 };
        assert_eq!(d["proposal"]["votedAtInertia"], at, "{group} {code}");
    }
    // And votable: in Monnaie libre, judged at level 4.
    let (_, _, e1_ml) = &proposals[1];
    c.vote(e1_ml, "for").await;
    let d = c.get(&format!("/api/proposals/{e1_ml}")).await;
    let ratio = d["proposal"]["evaluation"]["requiredRatio"].as_f64().expect("ratio");
    let p = d["participation"]["ratio"].as_f64().expect("p");
    let scale = Scale { electorate: 5745, floor: 50.0, participation: p };
    assert!((ratio - required_ratio(5745, 1, &scale.params(level(4)))).abs() < 1e-12);
    assert!((ratio - required_ratio(5745, 1, &scale.params(level(3)))).abs() > 1e-6, "not at the old level");
    assert_eq!(d["proposal"]["evaluation"]["required"], 50);
    // Republished where the document publishes; never from the test group.
    let queued: Vec<(String, String)> = sqlx::query_as(
        "SELECT d.group_slug, o.reason FROM outbox o JOIN documents d ON d.id = o.doc_id
          WHERE o.reason LIKE 'inertie%' ORDER BY o.id",
    )
    .fetch_all(&pool)
    .await
    .expect("outbox");
    assert_eq!(
        queued,
        [
            ("monnaie-libre".to_owned(), "inertie de départ relevée : E1, 3 → 4".to_owned()),
            ("monnaie-libre".to_owned(), "inertie de départ relevée : E2, 3 → 4".to_owned()),
        ]
    );
    // Once only: the next start changes nothing.
    let again = restart(&pool).await;
    assert_eq!(inertia_decisions(&again.db).await, first);
    let changes: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM inertia_changes").fetch_one(&pool).await.expect("n");
    assert_eq!(changes, 4);
}

#[tokio::test]
async fn an_inertia_changed_by_a_vote_keeps_its_level() {
    let (pool, _) = base_before_levels("voted").await;
    // The migration runs; a vote changes E2's inertia in the test group, before the
    // version that knows the amendment starts.
    let mut all = sqlx::migrate!("./migrations");
    all.set_ignore_missing(true);
    all.run(&pool).await.expect("migrations");
    let between = AppState::new(Config::for_tests(), pool.clone()).await.expect("state");
    let mut a = Client::of(&between);
    a.login("Yvv").await;
    let mut b = a.other();
    b.login("Chiara").await;
    let e2 = unit_id(&pool, "essai", "E2").await;
    let (s, v) = a.call("POST", &format!("/api/units/{e2}/inertia"), Some(json!({ "target": 5 }))).await;
    assert_eq!(s, StatusCode::OK, "{v}");
    let p = v["id"].as_str().expect("id").to_owned();
    a.vote(&p, "for").await;
    assert_eq!(b.vote(&p, "for").await["entered"][0]["kind"], "inertia");

    let state = restart(&pool).await;
    assert_eq!(
        decided(&inertia_decisions(&state.db).await),
        [
            ("essai", "E1", "applied", None),
            ("essai", "E2", "refused", Some("changed_by_vote")),
            ("monnaie-libre", "E1", "applied", None),
            ("monnaie-libre", "E2", "applied", None),
        ]
    );
    let mut c = Client::of(&state);
    c.login("Yvv").await;
    let doc = c.doc("essai").await;
    assert_eq!(unit(&doc, "E2")["inertia"], 5, "the vote holds");
}