From 55794ea464b22e20fbb53c10fb32ad5727a7e1dc Mon Sep 17 00:00:00 2001
From: "@permadeath.com" <did:plc:nlzmjyfv6loqtxyzvdcznwgf>
Date: Mon, 17 Aug 2026 19:51:22 -0400
Subject: [PATCH] test(scenarios): gate the generated figures against what they
 came from

Two committed artifacts that nothing checked against each other, which is the
same shape as the report drift #240 guarded.

unit-stats.json is collected from the two report.json files and neither
regenerates the other, so a refreshed report left every weight on a force card
describing a machine that may no longer be in the fight. The script has had a
--check since it was written and nothing ran it; prek does now. It is hermetic
and takes 46ms, unlike boards.json or megamek-text.ts, which need MegaMek and
so cannot be gated this way.

daily.json's per-unit battle values and its side totals come from different
parts of the same report, and nothing compared them. Summing one against the
other is also what says `mms index`'s positional join still lines up: the
report lists a faction in MegaMek's order, and if that stopped matching the
file's order the units would keep their names and swap their values - no total
would move, every row would be wrong. Two of Bug Company's Stingers differ by
124 BV on skills alone.

Both checked by mutation: a hand-edited weight fails the hook, a hand-edited
per-unit value fails the test.
---
 prek.toml                  | 16 ++++++++++++
 web/scripts/daily.test.mjs | 52 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/prek.toml b/prek.toml
index 7d4799f..6e4697d 100644
--- a/prek.toml
+++ b/prek.toml
@@ -92,6 +92,22 @@ files = '^plan/.*\.md$'
 # touching plan/ is a human writing prose in these same files, and a hook that
 # edited the register underneath them would be changing the thing being
 # written rather than reporting on it.
+# The unit table against the reports it is collected from. Both are committed
+# and neither regenerates the other, so a report refreshed without re-running
+# the script leaves every weight on a force card describing a machine that is
+# no longer in the fight - and a stale figure renders exactly as well as a
+# current one.
+#
+# Hermetic and instant: the inputs are the two report.json files in this repo,
+# so unlike boards.json or megamek-text.ts this needs no MegaMek to check.
+[[repos.hooks]]
+id = "unit-stats"
+name = "unit stats"
+language = "system"
+entry = "scripts/unit-stats.py --out web/src/content/unit-stats.json --check"
+pass_filenames = false
+files = '^(scripts/unit-stats\.py|web/src/content/unit-stats\.json|services/api/src/matches/(daily|scenarios)/report\.json)$'
+
 [[repos.hooks]]
 id = "plan-register"
 name = "plan register"
diff --git a/web/scripts/daily.test.mjs b/web/scripts/daily.test.mjs
index 8339ce1..2bf54a1 100644
--- a/web/scripts/daily.test.mjs
+++ b/web/scripts/daily.test.mjs
@@ -304,6 +304,58 @@ test("every rule a challenge switches has MegaMek's own description", async () =
   }
 });
 
+test("each side's battle value is the sum of the units in it", () => {
+  // daily.json is generated from the scenarios and arena's report of what they
+  // are worth, and the per-unit figures and the side total come from different
+  // parts of that report. If they ever disagree, one of them is describing a
+  // fight nobody is playing - and a wrong battle value renders exactly as well
+  // as a right one, so nothing else would notice.
+  //
+  // This is also what says the positional join in `mms index` still lines up:
+  // the report lists a faction in MegaMek's own order, and if that stopped
+  // matching the file's order the units would keep their names and swap their
+  // values, which changes no total but every row. Two of Bug Company's
+  // Stingers differ by 124 BV on skills alone.
+  for (const challenge of challenges) {
+    for (const side of challenge.sides) {
+      const known = side.units.filter((unit) => unit.bv !== undefined);
+      if (known.length === 0) continue;
+      assert.equal(
+        known.length,
+        side.units.length,
+        `${challenge.slug} ${side.name}: some units carry a battle value and ` +
+          `some do not, so the total cannot be checked against them`,
+      );
+      const summed = known.reduce((total, unit) => total + unit.bv, 0);
+      assert.equal(
+        summed,
+        side.bv,
+        `${challenge.slug} ${side.name}: the units add up to ${summed} but ` +
+          `the side says ${side.bv}`,
+      );
+    }
+  }
+});
+
+test("a daily's crews are carried, because the battle values depend on them", () => {
+  // BV 2.0 multiplies by gunnery and piloting, so a figure without the skills
+  // that produced it cannot be checked by anything, here or by a reader.
+  for (const challenge of challenges) {
+    for (const side of challenge.sides) {
+      for (const unit of side.units) {
+        if (unit.bv === undefined) continue;
+        assert.equal(
+          typeof unit.gunnery,
+          "number",
+          `${challenge.slug} ${side.name} ${unit.name}: a battle value with ` +
+            `no gunnery behind it`,
+        );
+        assert.equal(typeof unit.piloting, "number", `${unit.name} piloting`);
+      }
+    }
+  }
+});
+
 test("a rule the card shows is one somebody chose to show", async () => {
   // Disclosure is a property of the lock, not a second kind of lock: a daily
   // pins its map and its planetary conditions too, and those are equally
-- 
2.51.2