diff --git a/package.json b/package.json
index bdd746a0f..6559da12c 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
     "build": "tsc -p ./tsconfig.build.json",
     "cli": "node -r ts-node/register -r tsconfig-paths/register src/cli/index.ts",
     "cli:debug": "node -r ts-node/register -r tsconfig-paths/register --inspect-brk src/cli/index.ts",
-    "generate-assets": "node ./scripts/generate-assets.js",
+    "generate-assets": "node -r ts-node/register ./scripts/generate-assets.ts",
     "inline-version": "./scripts/inline-version.js",
     "lint.fix": "yarn lint --fix",
     "lint": "tsc --noEmit && tslint 'src/**/*.ts'",
@@ -49,7 +49,7 @@
     "prebuild": "yarn build.clean && copyfiles -u 1 \"src/rulesets/oas*/**/*.json\" dist && copyfiles -u 1 \"src/rulesets/oas*/**/*.json\" ./ && yarn copy.html-templates",
     "prebuild.binary": "yarn build",
     "pretest.karma": "node ./scripts/generate-karma-fixtures.js && yarn pretest",
-    "pretest": "node ./scripts/generate-assets.js",
+    "pretest": "yarn generate-assets",
     "schema.update": "yarn typescript-json-schema --id \"http://stoplight.io/schemas/rule.schema.json\" --required tsconfig.json IRule --out ./src/meta/rule.schema.json",
     "test.harness": "jest -c ./jest.harness.config.js",
     "test.karma": "karma start",
diff --git a/scripts/generate-assets.js b/scripts/generate-assets.js
deleted file mode 100755
index c910ef4a7..000000000
--- a/scripts/generate-assets.js
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/usr/bin/env node
-/**
- * This script generates a list of assets that are needed to load spectral:oas ruleset.
- * It contains all OAS custom functions and *resolved* rulesets.
- * The assets are stores in a single filed call assets.json in the following format:
- * `<require-call-path>: <content>`
- * where the `require-call-path` is the path you'd normally pass to require(), i.e. `@stoplight/spectral/rulesets/oas/index.js` and `content` is the text data.
- * Assets can be loaded using Spectral#registerStaticAssets statc method, i.e. `Spectral.registerStaticAssets(require('@stoplight/spectral/rulesets/assets/assets.json'))`;
- * If you execute the code above, ruleset will be loaded fully offline, without a need to make any request.
- */
-
-const path = require('@stoplight/path');
-const fs = require('fs');
-const { promisify } = require('util');
-const { parse } = require('@stoplight/yaml');
-const { httpAndFileResolver } = require('../dist/resolvers/http-and-file');
-
-const readFileAsync = promisify(fs.readFile);
-const writeFileAsync = promisify(fs.writeFile);
-const readdirAsync = promisify(fs.readdir);
-const statAsync = promisify(fs.stat);
-
-const baseDir = path.join(__dirname, '../rulesets/assets/');
-
-if (!fs.existsSync(baseDir)) {
-  fs.mkdirSync(baseDir);
-}
-
-const target = path.join(baseDir, `assets.json`);
-const assets = {};
-
-(async () => {
-  await processDirectory(assets, path.join(__dirname, '../rulesets/oas'));
-  await writeFileAsync(target, JSON.stringify(assets, null, 2));
-})();
-
-async function processDirectory(assets, dir) {
-  await Promise.all((await readdirAsync(dir)).map(async name => {
-    if (name === 'schemas') return;
-    const target = path.join(dir, name);
-    const stats = await statAsync(target);
-    if (stats.isDirectory()) {
-      return processDirectory(assets, target);
-    } else {
-      let content = await readFileAsync(target, 'utf8');
-      if (path.extname(name) === '.json') {
-        content = JSON.stringify((await httpAndFileResolver.resolve(JSON.parse(content), {
-          dereferenceRemote: true,
-          dereferenceInline: false,
-          baseUri: target,
-          parseResolveResult(opts) {
-            opts.result = parse(opts.result);
-            return opts;
-          },
-        })).result);
-      }
-
-      assets[path.join('@stoplight/spectral', path.relative(path.join(__dirname, '..'), target))] = content;
-    }
-  }));
-}
diff --git a/scripts/generate-assets.ts b/scripts/generate-assets.ts
new file mode 100644
index 000000000..b68995a76
--- /dev/null
+++ b/scripts/generate-assets.ts
@@ -0,0 +1,68 @@
+/**
+ * This script generates a list of assets that are needed to load spectral:oas ruleset.
+ * It contains all OAS custom functions and *resolved* rulesets.
+ * The assets are stores in a single filed call assets.json in the following format:
+ * `<require-call-path>: <content>`
+ * where the `require-call-path` is the path you'd normally pass to require(), i.e. `@stoplight/spectral/rulesets/oas/index.js` and `content` is the text data.
+ * Assets can be loaded using Spectral#registerStaticAssets statc method, i.e. `Spectral.registerStaticAssets(require('@stoplight/spectral/rulesets/assets/assets.json'))`;
+ * If you execute the code above, ruleset will be loaded fully offline, without a need to make any request.
+ */
+
+import { IUriParserResult } from '@stoplight/json-ref-resolver/types';
+import * as path from '@stoplight/path';
+import { parse } from '@stoplight/yaml';
+import * as fs from 'fs';
+import { promisify } from 'util';
+import { httpAndFileResolver } from '../dist/resolvers/http-and-file';
+
+const readFileAsync = promisify(fs.readFile);
+const writeFileAsync = promisify(fs.writeFile);
+const readdirAsync = promisify(fs.readdir);
+const statAsync = promisify(fs.stat);
+
+const baseDir = path.join(__dirname, '../rulesets/assets/');
+
+if (!fs.existsSync(baseDir)) {
+  fs.mkdirSync(baseDir);
+}
+
+const assetsPath = path.join(baseDir, `assets.json`);
+const generatedAssets = {};
+
+(async () => {
+  await processDirectory(generatedAssets, path.join(__dirname, '../rulesets/oas'));
+  await writeFileAsync(assetsPath, JSON.stringify(generatedAssets, null, 2));
+})();
+
+async function processDirectory(assets: Record<string, string>, dir: string) {
+  await Promise.all(
+    (await readdirAsync(dir)).map(async (name: string) => {
+      if (name === 'schemas') return;
+      const target = path.join(dir, name);
+      const stats = await statAsync(target);
+      if (stats.isDirectory()) {
+        return processDirectory(assets, target);
+      } else {
+        let content = await readFileAsync(target, 'utf8');
+        if (path.extname(name) === '.json') {
+          content = JSON.stringify(
+            (
+              await httpAndFileResolver.resolve(JSON.parse(content), {
+                dereferenceRemote: true,
+                dereferenceInline: false,
+                baseUri: target,
+                parseResolveResult(opts) {
+                  return new Promise<IUriParserResult>(resolve => {
+                    resolve({ result: parse(opts.result) });
+                  });
+                },
+              })
+            ).result,
+          );
+        }
+
+        assets[path.join('@stoplight/spectral', path.relative(path.join(__dirname, '..'), target))] = content;
+      }
+    }),
+  );
+}
diff --git a/scripts/generate-karma-fixtures.js b/scripts/generate-karma-fixtures.js
index 9bef59baa..9503fc2a1 100755
--- a/scripts/generate-karma-fixtures.js
+++ b/scripts/generate-karma-fixtures.js
@@ -8,9 +8,9 @@ if (!fs.existsSync(baseDir)) {
   fs.mkdirSync(baseDir);
 }
 
-for (const spec of ['', '2', '3']) {
-  const target = path.join(baseDir, `oas${spec}-functions.json`);
-  const fnsPath = path.join(__dirname, `../rulesets/oas${spec}/functions`);
+for (const rulesetName of ['oas']) {
+  const target = path.join(baseDir, `${rulesetName}-functions.json`);
+  const fnsPath = path.join(__dirname, `../rulesets/${rulesetName}/functions`);
   const bundledFns = {};
 
   if (fs.existsSync(fnsPath)) {
diff --git a/src/__tests__/generate-assets.jest.test.ts b/src/__tests__/generate-assets.jest.test.ts
new file mode 100644
index 000000000..f9609b16e
--- /dev/null
+++ b/src/__tests__/generate-assets.jest.test.ts
@@ -0,0 +1,38 @@
+import { existsSync, readFileSync } from 'fs';
+
+describe('generate-assets', () => {
+  let assets: Record<string, string>;
+
+  beforeAll(() => {
+    const path = __dirname + '/../../rulesets/assets/assets.json';
+    if (!existsSync(path)) {
+      fail('Missing assets.json file. Please run `yarn generate-assets`.');
+    }
+
+    const content = readFileSync(path, { encoding: 'utf8' });
+    assets = JSON.parse(content);
+    expect(assets).not.toBeUndefined();
+    expect(Object.keys(assets).length).toBeGreaterThan(1);
+  });
+
+  describe('produces properly serialized built-in rulesets', () => {
+    const testCases = [
+      ['oas', 'oas2-schema', 'title', 'A JSON Schema for Swagger 2.0 API.'],
+      ['oas', 'oas3-schema', 'description', 'Validation schema for OpenAPI Specification 3.0.X.'],
+    ];
+
+    it.each(testCases)(
+      "Ruleset '%s' contains a rule '%s' with an inlined schema bearing a '%s' property",
+      (ruleset: string, ruleName: string, schemaKey: string, schemaValue: string) => {
+        const key = `@stoplight/spectral/rulesets/${ruleset}/index.json`;
+        expect(Object.keys(assets)).toContain(key);
+        const content = JSON.parse(assets[key]);
+        const rule = content.rules[ruleName];
+        expect(rule).not.toBeUndefined();
+        const schema = rule.then.functionOptions.schema;
+        expect(schema[schemaKey]).not.toBeUndefined();
+        expect(schema[schemaKey]).toEqual(schemaValue);
+      },
+    );
+  });
+});
diff --git a/src/rulesets/__tests__/offline.schemas.jest.test.ts b/src/rulesets/__tests__/offline.schemas.jest.test.ts
index d037f41d9..227c086fe 100644
--- a/src/rulesets/__tests__/offline.schemas.jest.test.ts
+++ b/src/rulesets/__tests__/offline.schemas.jest.test.ts
@@ -85,7 +85,7 @@ describe('Online vs Offline context', () => {
   test('all rulesets are accounted for', async () => {
     const dir = path.join(__dirname, '../../../rulesets/');
 
-    // Would that fail, run  `yarn generate-assets` ;-)
+    // Would that fail, run  `yarn build` ;-)
     expect(fs.existsSync(dir)).toBeTruthy();
 
     const discoveredRulesets: string[] = [];