Add type-level test harness (pnpm test:types)

.prettierignore

@@ -0,0 +1,4 @@
+# Type-level test files use intentional long, single-line cases so that each
+# `@ts-expect-error` attaches to the error on the line immediately below it.
+# Prettier's line wrapping would move the error off that line and break them.
+*.test-d.ts

package.json

@@ -11,6 +11,7 @@
     "release": "pnpm publish --no-git-checks",
     "test": "vitest",
     "test:e2e": "vitest --mode e2e --reporter=verbose --test-timeout 10000",
+    "test:types": "vitest --run --mode types",
     "format": "prettier --write \"**/*.{ts,tsx,md,json,css,scss,html}\""
   },
   "sideEffects": false,

src/test/schema/Country.json

@@ -21,6 +21,10 @@
     {
       "type": "Decimal",
       "name": "population"
+    },
+    {
+      "type": "Int",
+      "name": "rank"
     }
   ]
 }

src/test/types-setup.ts

@@ -0,0 +1,8 @@
+import { generateCode } from "./client.utils";
+
+// The type tests import the generated test client (`./db/models`), which is
+// not committed — generate it up front, like the e2e setup does, but without
+// the database container: only tsc consumes the result.
+export function setup() {
+  generateCode();
+}

tsconfig.typecheck.json

@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "incremental": false,
+    "composite": false
+  },
+  "include": ["src/test/**/*.test-d.ts"],
+  "exclude": ["node_modules", "dist"]
+}

vitest.config.ts

@@ -17,8 +17,27 @@ const e2eTests: ViteUserConfig["test"] = {
   maxWorkers: 1,
 };
 
+// Type-level tests (`*.test-d.ts`), checked by tsc via Vitest's typecheck mode.
+// No runtime / DB — the client is `declare`d in the test files; the global
+// setup only generates the test client code the suite typechecks against.
+const typeTests: ViteUserConfig["test"] = {
+  include: [],
+  globalSetup: ["src/test/types-setup.ts"],
+  typecheck: {
+    enabled: true,
+    only: true,
+    include: ["src/test/**/*.test-d.ts"],
+    tsconfig: "tsconfig.typecheck.json",
+  },
+};
+
 export default defineConfig((env) => {
-  const testConfig = env.mode === "e2e" ? e2eTests : unitTests;
+  const testConfig =
+    env.mode === "e2e"
+      ? e2eTests
+      : env.mode === "types"
+        ? typeTests
+        : unitTests;
   return {
     plugins: [
       {