Cover the #DEX registry projection fix with a targeted test

tests/gen2_pokedex_text_registry_test.lua

@@ -0,0 +1,91 @@
+-- The #DEX screen (src/ui/gen2/PokedexMenu.lua) reads its KIND label and
+-- description pages from data.gen2Pokedex.entries, a table loaded straight
+-- from disk before mods:load runs -- a separate table from data.pokemon,
+-- the `pokemon` registry's own merge target
+-- (mod.content.pokemon:patch(id, { dexEntry = ... })). Without a projection
+-- step, a translation mod's #DEX text validates against the registry and
+-- never reaches the screen. src/core/gen2/PokedexText.lua is that
+-- projection, called once after the merge (src/core/Game2.lua). ROM-free:
+--   luajit tests/gen2_pokedex_text_registry_test.lua
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+local S = require("tests.harness").suite("gen2 pokedex text registry")
+local check, eq = S.check, S.eq
+
+local PokedexText = require("src.core.gen2.PokedexText")
+
+-- A patched species (CYNDAQUIL, kind/text/text2 all overridden), one left
+-- alone (TOTODILE, no dexEntry at all in data.pokemon -- a mod that never
+-- touched it), and one gen2Pokedex has no matching data.pokemon row for
+-- (UNOWN, e.g. a form gen2Pokedex tracks that the pokemon registry does not).
+do
+  local data = {
+    pokemon = {
+      CYNDAQUIL = { name = "CYNDAQUIL", dexEntry = {
+        kind = "SOURIS DE FEU", text = "Page un traduite.",
+        text2 = "Page deux traduite.",
+      } },
+      TOTODILE = { name = "TOTODILE" },
+    },
+    gen2Pokedex = { entries = {
+      CYNDAQUIL = { id = "CYNDAQUIL", dex = 155, kind = "FIRE MOUSE",
+        height = 108, weight = 170,
+        text = "It is timid, and always curls itself up in a ball.",
+        text2 = "If attacked, it flares up its back for protection." },
+      TOTODILE = { id = "TOTODILE", dex = 158, kind = "BIG JAW",
+        height = 200, weight = 200, text = "English page one.",
+        text2 = "English page two." },
+      UNOWN = { id = "UNOWN", dex = 201, kind = "SYMBOL",
+        height = 50, weight = 50, text = "English only." },
+    } },
+  }
+
+  local touched = PokedexText.apply(data)
+  eq(touched, 1, "only the species a mod actually patched are touched")
+
+  local cyndaquil = data.gen2Pokedex.entries.CYNDAQUIL
+  eq(cyndaquil.kind, "SOURIS DE FEU", "kind reaches the #DEX entry")
+  eq(cyndaquil.text, "Page un traduite.", "page one reaches the #DEX entry")
+  eq(cyndaquil.text2, "Page deux traduite.", "page two reaches the #DEX entry")
+  eq(cyndaquil.dex, 155, "dex number is untouched -- it is not translatable text")
+  eq(cyndaquil.height, 108, "height is untouched -- game state, not prose")
+  eq(cyndaquil.weight, 170, "weight is untouched -- game state, not prose")
+
+  local totodile = data.gen2Pokedex.entries.TOTODILE
+  eq(totodile.kind, "BIG JAW", "a species with no dexEntry patch stays in English")
+  eq(totodile.text, "English page one.", "unpatched page one is untouched")
+
+  local unown = data.gen2Pokedex.entries.UNOWN
+  eq(unown.kind, "SYMBOL",
+    "a #DEX entry with no data.pokemon counterpart at all is left alone")
+end
+
+-- A patch that only sets `kind` (species_kinds without species_dex_text
+-- shipped, or vice versa) must not blank out the fields it did not touch.
+do
+  local data = {
+    pokemon = { ABRA = { name = "ABRA", dexEntry = { kind = "PSY" } } },
+    gen2Pokedex = { entries = {
+      ABRA = { id = "ABRA", dex = 63, kind = "PSI",
+        text = "English text.", text2 = "English text two." },
+    } },
+  }
+  PokedexText.apply(data)
+  local abra = data.gen2Pokedex.entries.ABRA
+  eq(abra.kind, "PSY", "kind alone is applied")
+  eq(abra.text, "English text.", "text is left alone when the patch omits it")
+  eq(abra.text2, "English text two.", "text2 is left alone when the patch omits it")
+end
+
+-- Missing tables at every level answer 0 rather than raising -- a Gen 1 boot,
+-- or a Gold boot with no mods loaded, never calls this with a shaped table.
+do
+  eq(PokedexText.apply(nil), 0, "nil data does not raise")
+  eq(PokedexText.apply({}), 0, "empty data does not raise")
+  eq(PokedexText.apply({ gen2Pokedex = { entries = {} } }), 0,
+    "no data.pokemon at all does not raise")
+end
+
+check(true, "PokedexText.apply covers the projection this fix adds")
+
+S.finish()