test: add PadelMatch engine test suite (failing)

Writes the complete TDD test suite for PadelMatch before the engine
exists. Build intentionally fails to compile (RED phase) — undefined
symbols PadelMatch, RulesConfig, US, THEM, and QUAD_* constants are all
defined in Task 3.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

source/PadelMatchTest.mc

@@ -0,0 +1,156 @@
+import Toybox.Lang;
+import Toybox.Test;
+
+// ---- plain helpers (not annotated :test, so not run as cases) ----
+
+function newMatch() as PadelMatch {
+    return new PadelMatch(new RulesConfig());
+}
+
+function newAdvantageMatch() as PadelMatch {
+    var r = new RulesConfig();
+    r.goldenPoint = false;
+    return new PadelMatch(r);
+}
+
+// Win one game for `team` under golden-point rules (4 straight points).
+function winGameFor(m as PadelMatch, team as Number) as Void {
+    for (var i = 0; i < 4; i += 1) { m.pointTo(team); }
+}
+
+// ---- test cases ----
+
+(:test) function testInitialState(logger as Logger) as Boolean {
+    var m = newMatch();
+    Test.assertEqualMessage(m.sets(US), 0, "sets US");
+    Test.assertEqualMessage(m.games(US), 0, "games US");
+    Test.assertEqualMessage(m.pointLabel(US), "0", "points US");
+    Test.assertEqualMessage(m.isMatchOver(), false, "not over");
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_BOTTOM_RIGHT, "US serves deuce");
+    return true;
+}
+
+(:test) function testPointLabelsProgress(logger as Logger) as Boolean {
+    var m = newMatch();
+    m.pointTo(US);
+    Test.assertEqualMessage(m.pointLabel(US), "15", "15");
+    m.pointTo(US);
+    Test.assertEqualMessage(m.pointLabel(US), "30", "30");
+    m.pointTo(US);
+    Test.assertEqualMessage(m.pointLabel(US), "40", "40");
+    return true;
+}
+
+(:test) function testGoldenGameWin(logger as Logger) as Boolean {
+    var m = newMatch();
+    winGameFor(m, US);
+    Test.assertEqualMessage(m.games(US), 1, "US won a game");
+    Test.assertEqualMessage(m.pointLabel(US), "0", "points reset");
+    return true;
+}
+
+(:test) function testAdvantageDeuceCycle(logger as Logger) as Boolean {
+    var m = newAdvantageMatch();
+    // 3-3 deuce
+    for (var i = 0; i < 3; i += 1) { m.pointTo(US); m.pointTo(THEM); }
+    Test.assertEqualMessage(m.pointLabel(US), "40", "deuce US 40");
+    m.pointTo(US);
+    Test.assertEqualMessage(m.pointLabel(US), "AD", "US advantage");
+    m.pointTo(THEM);
+    Test.assertEqualMessage(m.pointLabel(US), "40", "back to deuce");
+    m.pointTo(US); m.pointTo(US);
+    Test.assertEqualMessage(m.games(US), 1, "US won from advantage");
+    return true;
+}
+
+(:test) function testWinSetSixLove(logger as Logger) as Boolean {
+    var m = newMatch();
+    for (var g = 0; g < 6; g += 1) { winGameFor(m, US); }
+    Test.assertEqualMessage(m.sets(US), 1, "US won the set");
+    Test.assertEqualMessage(m.games(US), 0, "games reset");
+    return true;
+}
+
+(:test) function testTiebreakEntryAndWin(logger as Logger) as Boolean {
+    var m = newMatch();
+    for (var i = 0; i < 6; i += 1) { winGameFor(m, US); winGameFor(m, THEM); }
+    Test.assertEqualMessage(m.isInTiebreak(), true, "6-6 tiebreak");
+    Test.assertEqualMessage(m.games(US), 6, "games 6-6");
+    for (var p = 0; p < 7; p += 1) { m.pointTo(US); }
+    Test.assertEqualMessage(m.isInTiebreak(), false, "tiebreak done");
+    Test.assertEqualMessage(m.sets(US), 1, "US won the set via tiebreak");
+    return true;
+}
+
+(:test) function testServeSideParity(logger as Logger) as Boolean {
+    var m = newMatch();                                    // US serving
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_BOTTOM_RIGHT, "0 pts deuce");
+    m.pointTo(THEM);                                       // 1 point played
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_BOTTOM_LEFT, "1 pt ad");
+    m.pointTo(US);                                         // 2 points played
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_BOTTOM_RIGHT, "2 pts deuce");
+    return true;
+}
+
+(:test) function testServerAlternation(logger as Logger) as Boolean {
+    var m = newMatch();
+    winGameFor(m, US);                                     // serve passes to THEM
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_UPPER_LEFT, "THEM serves deuce");
+    return true;
+}
+
+(:test) function testTiebreakServing(logger as Logger) as Boolean {
+    var m = newMatch();
+    for (var i = 0; i < 6; i += 1) { winGameFor(m, US); winGameFor(m, THEM); }
+    // 12 games played, start server US -> US serves first in tiebreak
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_BOTTOM_RIGHT, "P0 US deuce");
+    m.pointTo(US);
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_UPPER_RIGHT, "P1 THEM ad");
+    m.pointTo(US);
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_UPPER_LEFT, "P2 THEM deuce");
+    m.pointTo(US);
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_BOTTOM_LEFT, "P3 US ad");
+    return true;
+}
+
+(:test) function testUndoAcrossGame(logger as Logger) as Boolean {
+    var m = newMatch();
+    winGameFor(m, US);                 // US 1 game, points 0-0, THEM to serve
+    m.pointTo(THEM);                   // THEM has 15
+    m.undo();                          // back to just-after-game
+    Test.assertEqualMessage(m.pointLabel(THEM), "0", "point undone");
+    m.undo();                          // undo the game-winning point
+    Test.assertEqualMessage(m.games(US), 0, "game undone");
+    Test.assertEqualMessage(m.pointLabel(US), "40", "back to 40");
+    return true;
+}
+
+(:test) function testUndoAtStartIsNoop(logger as Logger) as Boolean {
+    var m = newMatch();
+    m.undo();
+    Test.assertEqualMessage(m.games(US), 0, "still zero");
+    return true;
+}
+
+(:test) function testStartingServerToggle(logger as Logger) as Boolean {
+    var m = newMatch();
+    m.toggleStartingServer();
+    Test.assertEqualMessage(m.servingQuadrant(), QUAD_UPPER_LEFT, "THEM serves first");
+    m.pointTo(US);                     // match started; toggle now locked
+    m.toggleStartingServer();
+    Test.assertEqualMessage(m.canSetServer(), false, "server locked after first point");
+    return true;
+}
+
+(:test) function testMatchOver(logger as Logger) as Boolean {
+    var m = newMatch();
+    for (var s = 0; s < 2; s += 1) {
+        for (var g = 0; g < 6; g += 1) { winGameFor(m, US); }
+    }
+    Test.assertEqualMessage(m.isMatchOver(), true, "match over");
+    Test.assertEqualMessage(m.winner(), US, "US wins");
+    var setsBefore = m.sets(US);
+    m.pointTo(US);                     // ignored after match over
+    Test.assertEqualMessage(m.sets(US), setsBefore, "no scoring after match");
+    return true;
+}