chore: extract napiVersion into its own harness module

implementors/node/features.js

@@ -8,8 +8,6 @@ globalThis.experimentalFeatures = {
   postFinalizer: true,
 };
 
-globalThis.napiVersion = Number(process.versions.napi);
-
 globalThis.skipTest = () => {
   process.exit(0);
 };

implementors/node/napi-version.js

@@ -0,0 +1 @@
+globalThis.napiVersion = Number(process.versions.napi);

implementors/node/tests.ts

@@ -40,6 +40,12 @@ const MUST_CALL_MODULE_PATH = path.join(
   "node",
   "must-call.js"
 );
+const NAPI_VERSION_MODULE_PATH = path.join(
+  ROOT_PATH,
+  "implementors",
+  "node",
+  "napi-version.js"
+);
 
 export function listDirectoryEntries(dir: string) {
   const entries = fs.readdirSync(dir, { withFileTypes: true });
@@ -80,6 +86,8 @@ export function runFileInSubprocess(
         "file://" + GC_MODULE_PATH,
         "--import",
         "file://" + MUST_CALL_MODULE_PATH,
+        "--import",
+        "file://" + NAPI_VERSION_MODULE_PATH,
         filePath,
       ],
       { cwd }

tests/harness/napi-version.js

@@ -0,0 +1,6 @@
+'use strict';
+
+// napiVersion is a positive integer
+if (typeof napiVersion !== 'number' || napiVersion < 1 || !Number.isInteger(napiVersion)) {
+  throw new Error('Expected a global napiVersion that is a positive integer');
+}