Merge pull request 'Hold'em dealer: blind fix, design tokens, and the decrowd' (#116) from fix/naming-a-blind-deals-the-hand into master

Reviewed-on: #116

JoshHeaps.Net/Pages/Casino/TexasHoldem.cshtml

@@ -7,18 +7,23 @@
 
 <div id="holdemApp">
     <header id="holdemHeader">
+        @* Six equally-weighted buttons used to sit here in two rows, and on a 390px
+           phone the felt did not start until 225px down — a quarter of the screen spent
+           before the dealer saw the table. Only two of the six are per-hand controls.
+           The rest have gone where they belong rather than into a "more" menu, which
+           would have relocated the crowding rather than removed it: Reset Table to the
+           Session panel beside Clear history and the save/load pair, Quick Split down
+           with Common rulings where the other "open something else" link already lives,
+           and the way back to the site up top where a back link goes. *@
         <div id="holdemHeaderLeft">
+            <a href="/casino" class="holdemBackLink">← Casino</a>
             <h1>Texas Hold'em Dealer</h1>
-            <p class="holdemSubtitle">Seat your players, track the action, split the pot.</p>
             <span id="handCounterBadge" class="handCounterBadge">Hand #1</span>
         </div>
         <div id="holdemHeaderActions">
-            <a href="/casino/texasholdem/quicksplit" class="holdemBtn" title="Chop a pot without setting up a table">Quick Split</a>
             <button id="misdealBtn" class="holdemBtn" title="Take this hand back — every chip returns to the player who put it in, and the same button deals again" hidden>Misdeal</button>
             <button id="nextHandBtn" class="holdemBtn" title="Move the button, small blind and big blind to the next occupied seat">Next Hand ⟳</button>
             <button id="resolvePotBtn" class="holdemBtn holdemBtnAccent">Resolve Pot</button>
-            <button id="resetTableBtn" class="holdemBtn holdemBtnDanger">Reset Table</button>
-            <a href="/casino" class="holdemBtn holdemBtnGhost">← Casino</a>
         </div>
     </header>
 
@@ -37,6 +42,7 @@
             <p id="tableHint" class="tableHint"></p>
             <p class="tableHintActions">
                 <button type="button" id="openRulingsBtn" class="linkBtn">Common rulings</button>
+                <a href="/casino/texasholdem/quicksplit" class="linkBtn" title="Chop a pot without setting up a table">Quick Split</a>
             </p>
         </section>
 
@@ -52,7 +58,11 @@
                 </div>
             </section>
 
-            <details class="sidebarPanel" open>
+            @* Not `open` in the markup any more. Whether this panel starts open is a
+               question about the table, so main.js answers it after the state has
+               loaded: open on a table nobody has set up yet, shut on one already
+               half-way through a night. *@
+            <details class="sidebarPanel" id="tableSetupPanel">
                 <summary>Table Setup</summary>
                 <div class="panelBody">
                     <label class="fieldRow">
@@ -209,6 +219,11 @@
                         <button id="saveTableBtn" class="holdemBtn holdemBtnSmall">Save table file</button>
                         <button id="loadTableBtn" class="holdemBtn holdemBtnSmall">Load table file</button>
                         <input id="loadTableInput" type="file" accept="application/json,.json" hidden />
+                        @* Down from the header, where it sat in the same weight as Resolve Pot
+                           — the most-pressed control in a session next to the one that throws
+                           the night away. Here it is beside Clear history, which is the other
+                           thing that destroys records, and behind a panel you have to open. *@
+                        <button id="resetTableBtn" class="holdemBtn holdemBtnSmall holdemBtnDanger">Reset table</button>
                     </div>
                 </div>
             </details>

JoshHeaps.Net/wwwroot/js/casino/holdem/actionBar.js

@@ -231,7 +231,17 @@ const ActionBar = {
             undo.type = "button";
             undo.className = "actionUndo";
             undo.title = `Undo ${undoLabel}`;
-            undo.textContent = `↶ ${undoLabel}`;
+            // The label goes in its own element rather than straight onto the button.
+            // The pill is a fixed width — it names the last action, so its text changes
+            // on every tap, and a control that resizes under the dealer's thumb reads
+            // as the interface twitching. Fixed width means long labels have to
+            // ellipsize, and only a real element can: as a bare text node the label
+            // truncated *through* the keycap below it, which then sat squashed against
+            // the cut-off text looking like a rendering fault.
+            const label = document.createElement("span");
+            label.className = "actionUndoLabel";
+            label.textContent = `↶ ${undoLabel}`;
+            undo.appendChild(label);
             // U undoes, and nothing said so — this control was the only place a dealer
             // could have learned it, and it was the one action bar control without its
             // key printed on it.

JoshHeaps.Net/wwwroot/js/casino/holdem/betting.js

@@ -459,6 +459,25 @@ const Betting = {
         return (state.street || "preflop") === "preflop" && state.seats.every(p => !p.hasActed);
     },
 
+    // Are the blinds actually down? Moving the button or naming a blind means two
+    // completely different things depending on the answer, and `onlyBlindsIn` alone
+    // cannot tell them apart: a table sitting in setup, with no cards out and nothing
+    // committed, satisfies it just as well as a hand that has only just been dealt.
+    //
+    // With a hand open, the blinds are chips on the felt. Re-aiming them has to take
+    // those chips back and post them again from the new positions, or the badges and
+    // the money disagree.
+    //
+    // Before the deal it is a marker being slid round a table with nothing in the
+    // middle. Re-posting there would *deal the hand* — betting opened, blinds taken off
+    // two stacks, action on the seat after the big blind — which is not what a dealer
+    // means by "she's the big blind this one". Setting the positions is how a dealer
+    // gets ready to deal; the cards come out when they press the button, and not a
+    // moment before.
+    blindsArePosted(state) {
+        return !!state.bettingOpen && this.onlyBlindsIn(state);
+    },
+
     // Chips the pot has been priced with but nobody has actually paid.
     //
     // Two ways a contribution gets into this tool. Tapping the action moves chips: the

JoshHeaps.Net/wwwroot/js/casino/holdem/main.js

@@ -176,8 +176,7 @@ document.addEventListener("DOMContentLoaded", () => {
             // After it, the blinds have to follow the button or the badges and the
             // money disagree — but that's a real thing happening to real chips, and
             // the dealer gets told rather than finding out later.
-            const willRepost = state.bettingOpen && Betting.onlyBlindsIn(state) &&
-                HoldemState.unresolvedContributions(state) > Betting.EPSILON_CHIPS;
+            const willRepost = Betting.blindsArePosted(state);
 
             seatAction(index, willRepost
                 ? `Button on ${nameOf(index)} — blinds taken back and re-posted.`
@@ -204,18 +203,29 @@ document.addEventListener("DOMContentLoaded", () => {
             if (partner === index || partner === null) partner = Betting.nextLiveIndex(state, index);
 
             const label = which === "sb" ? "small blind" : "big blind";
-            seatAction(index, `${nameOf(index)} posts the ${label}.`, () => {
+            // Only a hand that is already open has blinds to move. Before the deal this
+            // is aiming the next hand, and re-posting would have dealt it — the dealer
+            // says who the blind is well before they say "cards".
+            const posted = Betting.blindsArePosted(state);
+            seatAction(index, posted
+                ? `${nameOf(index)} posts the ${label}.`
+                : `${nameOf(index)} has the ${label} next hand.`, () => {
                 state.blindOverride = which === "sb"
                     ? { sbIndex: index, bbIndex: partner }
                     : { sbIndex: partner, bbIndex: index };
-                if (Betting.onlyBlindsIn(state)) Betting.repostBlinds(state);
+                if (posted) Betting.repostBlinds(state);
             });
         },
 
-        clearBlindOverride: () => seatAction(state.dealerSeatIndex, "Blinds follow the button again.", () => {
+        clearBlindOverride: () => {
+            const posted = Betting.blindsArePosted(state);
+            seatAction(state.dealerSeatIndex, posted
+                ? "Blinds follow the button again — taken back and re-posted."
+                : "Blinds follow the button again.", () => {
                 state.blindOverride = null;
-            if (Betting.onlyBlindsIn(state)) Betting.repostBlinds(state);
-        }),
+                if (posted) Betting.repostBlinds(state);
+            });
+        },
 
         editSeat: index => Render.toggleSeatEditor(index),
 
@@ -247,6 +257,22 @@ document.addEventListener("DOMContentLoaded", () => {
 
     Render.mount(state, hooks);
 
+    // Table Setup used to ship open, so the tool's first screen was its most crowded
+    // one: seat count, blind direction, dedicated dealer, both blinds, starting stack
+    // and two sub-panels, all under a felt the dealer had come here to look at. It is
+    // the right panel to have open on a table nobody has touched, and the wrong one to
+    // have open on the fourth hand of a night.
+    //
+    // Decided once, here, rather than on every render — a panel that reopened itself
+    // whenever the table emptied would fight the dealer who had just shut it.
+    (() => {
+        const panel = document.getElementById("tableSetupPanel");
+        if (!panel) return;
+        const fresh = (Number(state.handNumber) || 1) === 1 &&
+            !state.seats.some(seat => HoldemState.seatInPlay(seat));
+        panel.open = fresh;
+    })();
+
     const openPotWizard = () => {
         // Chips still in front of players belong in the pot being priced, so bank them
         // before the wizard reads anyone's contribution.

JoshHeaps.Net/wwwroot/js/casino/holdem/render.js

@@ -88,6 +88,19 @@ const Render = {
         hint.textContent = this.canDragSeats()
             ? "Tap a seat to edit · double-tap to fold · press and hold for quick actions · drag to swap seats."
             : "Tap a seat to edit · double-tap to fold · press and hold for quick actions, including moving a seat.";
+
+        // But only on the first hand. Two lines of instructions under the felt are worth
+        // having on a table nobody has dealt at yet, and worth nothing on the fifth hand
+        // of the night — by then the dealer either knows the gestures or is not going to
+        // learn them from a caption they have scrolled past forty times.
+        //
+        // Keyed to the hand number rather than to whether a hand is currently out, on
+        // purpose. `bettingOpen` was the obvious test and it is the wrong one: the hint
+        // would vanish at every deal and come back at every payout, so a two-line block
+        // under the felt would appear and disappear twice a hand, shunting the rulings
+        // link and the whole panel stack up and down all night. This way it goes once,
+        // at the first deal of the session, and stays gone.
+        hint.hidden = (Number(this.state.handNumber) || 1) > 1 || !!this.state.bettingOpen;
     },
 
     renderNotes() {
@@ -553,8 +566,21 @@ const Render = {
     // font down keeps every digit, which matters: a dealer misreading a stack is a
     // worse outcome than a small one, so this shrinks rather than abbreviating.
     fitAmount(el) {
-        const length = (el.textContent || "").length;
+        const formatted = el.textContent || "";
+        // The separators go before the type size does. "$1,234,567" is ten characters,
+        // which used to drop the puck to 7px — and 7px is not a size anybody reads a
+        // stack off a felt at, so the shrink-rather-than-abbreviate rule above was
+        // buying precision the dealer then couldn't see. Without its commas the same
+        // number is eight characters, and eight fits at 10px with every digit intact.
+        // Grouping is a reading aid for a column of figures; this is one number on a
+        // 64px puck, and the aid costs more than it gives.
+        const text = formatted.length >= 10 ? formatted.replace(/,/g, "") : formatted;
+        if (text !== formatted) el.textContent = text;
+
+        const length = text.length;
         el.classList.toggle("puckAmountLong", length >= 8 && length < 10);
+        // Only a stack of $100,000,000 or more still lands here. It is an overflow
+        // guard rather than a size anybody is expected to read.
         el.classList.toggle("puckAmountHuge", length >= 10);
     },
 

tests/holdem/aimingTheBlinds.test.js

@@ -0,0 +1,128 @@
+// Saying who the blind is, before saying "cards".
+//
+// A dealer sets the table up out loud — button here, she's the small blind, he's the
+// big blind — and only then deals. The seat menu offers "Make small blind" for exactly
+// that, and it was answering by dealing the hand: betting opened, two stacks docked,
+// the action bar up and waiting on the seat after the big blind. The dealer had said
+// where the blinds go, and the tool heard "deal".
+//
+// The condition it was asking is `onlyBlindsIn`, which means "nothing has happened in
+// this hand except the blinds" — true of a hand one second old, and equally true of a
+// table in setup with no cards out and nothing committed. Those two need telling apart,
+// which is what `blindsArePosted` is for.
+const test = require("node:test");
+const { describe } = require("node:test");
+const assert = require("node:assert");
+const { Betting, HoldemState, makeTable, chipsOnTable } = require("./load");
+
+describe("before the deal", () => {
+    test("the blinds are not down, however much the table looks ready", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3] });
+        assert.equal(state.bettingOpen, false);
+        // The old condition, on its own, says yes here — this is the whole bug.
+        assert.equal(Betting.onlyBlindsIn(state), true);
+        assert.equal(Betting.blindsArePosted(state), false);
+    });
+
+    test("a table straight out of setup, with nobody seated, is the same answer", () => {
+        assert.equal(Betting.blindsArePosted(HoldemState.createDefault()), false);
+    });
+
+    test("re-posting would have dealt the hand, which is why it is guarded", () => {
+        // Not a rule, a demonstration: repostBlinds ends in beginHand. Calling it in
+        // setup is the deal, and nothing about naming a blind should reach it.
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3] });
+        Betting.repostBlinds(state);
+        assert.equal(state.bettingOpen, true, "chips off two stacks and the action bar up");
+        assert.notEqual(state.actingSeatIndex, null);
+    });
+
+    test("naming a blind moves a badge and no chips", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3] });
+        const before = chipsOnTable(state);
+
+        // What the seat menu does: pin the override, repost only if the blinds are down.
+        state.blindOverride = { sbIndex: 3, bbIndex: 0 };
+        if (Betting.blindsArePosted(state)) Betting.repostBlinds(state);
+
+        assert.equal(state.bettingOpen, false, "still setup — the dealer hasn't dealt");
+        assert.equal(state.actingSeatIndex, null, "nobody is being asked to act");
+        assert.deepEqual(state.seats.map(p => Betting.committed(p)), [0, 0, 0, 0, 0, 0]);
+        assert.equal(chipsOnTable(state), before);
+
+        // And the badges say what the dealer just said.
+        const blinds = HoldemState.getBlindSeats(state);
+        assert.equal(blinds.sbIndex, 3);
+        assert.equal(blinds.bbIndex, 0);
+    });
+
+    test("and the hand that follows posts from where they were aimed", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3], smallBlind: 1, bigBlind: 2 });
+        state.blindOverride = { sbIndex: 3, bbIndex: 0 };
+        if (Betting.blindsArePosted(state)) Betting.repostBlinds(state);
+
+        Betting.beginHand(state);
+        assert.equal(Betting.committed(state.seats[3]), 1);
+        assert.equal(Betting.committed(state.seats[0]), 2);
+    });
+
+    test("giving the button away is a marker moving too", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3] });
+        const before = chipsOnTable(state);
+
+        const willRepost = Betting.blindsArePosted(state);
+        state.dealerSeatIndex = 2;
+        if (willRepost) Betting.repostBlinds(state);
+
+        assert.equal(willRepost, false);
+        assert.equal(state.bettingOpen, false);
+        assert.equal(chipsOnTable(state), before);
+    });
+});
+
+describe("once the hand is dealt", () => {
+    test("the blinds are down, and re-aiming them moves real chips", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        const before = chipsOnTable(state);
+        Betting.beginHand(state);
+        assert.equal(Betting.blindsArePosted(state), true);
+        assert.equal(Betting.committed(state.seats[1]), 1);
+
+        state.blindOverride = { sbIndex: 3, bbIndex: 0 };
+        if (Betting.blindsArePosted(state)) Betting.repostBlinds(state);
+
+        assert.equal(Betting.committed(state.seats[1]), 0, "the old small blind got their chip back");
+        assert.equal(Betting.committed(state.seats[3]), 1);
+        assert.equal(Betting.committed(state.seats[0]), 2);
+        assert.equal(chipsOnTable(state), before, "no chips created or lost in the shuffle");
+    });
+
+    test("but not once somebody has answered them", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.call(state, state.actingSeatIndex);
+        assert.equal(Betting.blindsArePosted(state), false, "there is a call to unpick now");
+    });
+
+    test("nor on a later street", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        state.street = "flop";
+        assert.equal(Betting.blindsArePosted(state), false);
+    });
+
+    test("and a misdealt hand goes back to being a table in setup", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.takeHandBack(state);
+        assert.equal(Betting.blindsArePosted(state), false, "nothing is posted until the dealer deals again");
+    });
+
+    test("as does a hand that has been paid out", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.sweepToHandTotals(state);
+        HoldemState.startNextHand(state);
+        assert.equal(Betting.blindsArePosted(state), false);
+    });
+});

tests/holdem/designTokens.test.js

@@ -0,0 +1,149 @@
+// The stylesheet has to keep picking from the scales.
+//
+// Before the token block went in, holdem.css used 42 different spacing values, 31 font
+// sizes, 14 border-radii and 139 colours, and defined three custom properties. None of
+// that was anybody's decision — each number was chosen at the moment it was needed, and
+// the result read as crowded even where nothing overlapped, because a 0.42rem gap next
+// to a 0.45rem gap next to a 0.5rem gap gives the eye no rhythm to lock onto.
+//
+// A one-off cleanup would last until the next `padding: 0.35rem`. So the scales are
+// checked here instead: a new value has to be a step on one of them, or an exception
+// with a reason written next to it.
+//
+// This reads the stylesheet as text rather than through a CSS parser, on purpose — the
+// rest of this suite has no dependencies and runs in a second, and a regex over
+// declarations is enough to catch the thing that actually happens, which is somebody
+// (me) typing a number instead of reaching for a token.
+const test = require("node:test");
+const { describe } = require("node:test");
+const assert = require("node:assert");
+const fs = require("fs");
+const path = require("path");
+
+const CSS_PATH = path.join(__dirname, "..", "..", "JoshHeaps.Net", "wwwroot", "css", "casino", "holdem.css");
+const css = fs.readFileSync(CSS_PATH, "utf8");
+
+// Comments carry measurements and rationale — "measured at 342px tall on a phone" —
+// and none of that is a declaration. Strip them before looking for values.
+const declarations = css.replace(/\/\*[\s\S]*?\*\//g, "");
+
+// Everything after the token block. The :root block is where the raw values are
+// supposed to be.
+const body = declarations.slice(declarations.indexOf("#potBadgeAmount,"));
+
+const valuesIn = (properties, source = body) => {
+    const found = [];
+    const re = new RegExp(`\\b(${properties.join("|")})\\s*:([^;}]*)`, "g");
+    let m;
+    while ((m = re.exec(source)) !== null) {
+        const [, prop, value] = m;
+        // calc() and env() do their own arithmetic on tokens; the tokens inside them
+        // are still checked, because the regex below looks at bare numbers only.
+        (value.match(/(?<![\w-])[0-9.]+(rem|px|em)\b/g) || []).forEach(v => found.push({ prop, value: v }));
+    }
+    return found;
+};
+
+describe("the spacing scale", () => {
+    // Hairlines and structural clearances, each one deliberate:
+    //   0px/1px/3px/4px/22px — borders, hairline offsets, and the 22px of room a seat
+    //                          puck's name gives the dealer button beside it.
+    //   5rem/9rem            — how far the page has to scroll past the fixed action
+    //                          bar. Not rhythm; clearance for a thing of a known size.
+    const ALLOWED = new Set(["0px", "1px", "2px", "3px", "4px", "22px", "5rem", "9rem"]);
+
+    test("every gap, margin and padding comes off the scale", () => {
+        const offenders = valuesIn(
+            ["padding", "padding-top", "padding-right", "padding-bottom", "padding-left",
+             "margin", "margin-top", "margin-right", "margin-bottom", "margin-left",
+             "gap", "row-gap", "column-gap"])
+            .filter(v => !ALLOWED.has(v.value));
+
+        assert.deepEqual(offenders, [],
+            "use var(--sp-0 … --sp-6), or add the value to ALLOWED with a reason");
+    });
+
+    test("and the scale is the one the tokens define", () => {
+        ["--sp-0", "--sp-1", "--sp-2", "--sp-3", "--sp-4", "--sp-5", "--sp-6"]
+            .forEach(token => assert.match(css, new RegExp(`\\${token}:`), `${token} is not defined`));
+    });
+});
+
+describe("the type scale", () => {
+    //   16px  — the size below which iOS zooms the page when a field is focused, so
+    //           every text input states it. Not a typographic choice.
+    //   1.05em, 0.44rem — relative bumps inside a component, and the shrink-to-fit for
+    //           a six-figure stack on a 58px seat puck.
+    const ALLOWED = new Set(["16px", "1.05em", "0.44rem"]);
+
+    test("every font-size comes off the scale", () => {
+        const offenders = valuesIn(["font-size"]).filter(v => !ALLOWED.has(v.value));
+        assert.deepEqual(offenders, [],
+            "use var(--fs-2xs … --fs-2xl), or add the value to ALLOWED with a reason");
+    });
+
+    test("and the scale is the one the tokens define", () => {
+        ["--fs-2xs", "--fs-xs", "--fs-sm", "--fs-base", "--fs-md", "--fs-lg", "--fs-xl", "--fs-2xl"]
+            .forEach(token => assert.match(css, new RegExp(`\\${token}:`), `${token} is not defined`));
+    });
+});
+
+describe("the corner scale", () => {
+    test("every border-radius comes off it", () => {
+        const offenders = valuesIn(["border-radius"]).filter(v => v.value !== "2px");
+        assert.deepEqual(offenders, [], "use var(--r-sm | --r-md | --r-lg | --r-pill)");
+    });
+});
+
+describe("the tokens themselves", () => {
+    test("every var() the stylesheet reaches for exists", () => {
+        const used = new Set((css.match(/var\((--[a-zA-Z0-9-]+)/g) || []).map(s => s.slice(4)));
+        // Published from JS at runtime rather than declared here — see actionBar.js.
+        const fromScript = new Set(["--actionBarHeight", "--feltRoomPx"]);
+        // Defined by the site's own stylesheet, not this one.
+        const fromSite = new Set(["--font-mono"]);
+        const missing = [...used].filter(t =>
+            !fromScript.has(t) && !fromSite.has(t) && !new RegExp(`\\${t}\\s*:`).test(css));
+        assert.deepEqual(missing, []);
+    });
+
+    test("and the dark surfaces stay off pure black", () => {
+        // Shadows are invisible on #000, so depth has to come from a lighter surface —
+        // and white text on true black is the pairing that smears on an OLED phone,
+        // which is what this tool is used on.
+        const surfaces = [...css.matchAll(/--surface-\d+:\s*(#[0-9a-fA-F]{3,8})/g)].map(m => m[1].toLowerCase());
+        assert.ok(surfaces.length >= 4, "the surface ramp should have four steps");
+        surfaces.forEach(hex => {
+            assert.notEqual(hex, "#000");
+            assert.notEqual(hex, "#000000");
+        });
+    });
+});
+
+describe("numbers that change while the dealer watches", () => {
+    test("are set in tabular figures", () => {
+        // A "1" is narrower than an "8" in a proportional face, so a pot ticking from
+        // $18 to $21 shuffles its digits sideways and the eye reads movement where
+        // there is only arithmetic.
+        assert.match(css, /font-variant-numeric:\s*tabular-nums/);
+        ["#potBadgeAmount", ".seatPuckStack", ".actionPot", ".standingsRow"]
+            .forEach(sel => assert.ok(css.includes(sel),
+                `${sel} should be in the tabular-figures list`));
+    });
+});
+
+describe("controls that must not resize under a thumb", () => {
+    test("the undo pill has a fixed width, not a content width", () => {
+        // It names the last action, so its label changes on every tap. Measured across
+        // one hand before this: 148, 110, 109, 108, 109, 110, 120.
+        const rule = css.match(/\.actionUndo\s*\{[^}]*\}/);
+        assert.ok(rule, ".actionUndo rule not found");
+        assert.match(rule[0], /width:\s*[0-9.]+rem/);
+    });
+
+    test("and its label is the part that ellipsizes", () => {
+        const rule = css.match(/\.actionUndoLabel\s*\{[^}]*\}/);
+        assert.ok(rule, ".actionUndoLabel rule not found");
+        assert.match(rule[0], /text-overflow:\s*ellipsis/);
+    });
+});