Add support for custom route file extensions.

test/apps/custom-extension/test.ts

@@ -0,0 +1,61 @@
+import * as assert from 'assert';
+import { build } from '../../../api';
+import { AppRunner } from '../AppRunner';
+
+describe('custom extensions', function() {
+	this.timeout(10000);
+
+	let r: AppRunner;
+
+	// hooks
+	before('build app', () => build({ cwd: __dirname , ext: '.jesuslivesineveryone .whokilledthemuffinman .mdx .svelte' }));
+	before('start runner', async () => {
+		r = await new AppRunner().start(__dirname);
+	});
+
+	after(() => r && r.end());
+
+
+	
+	it('works with arbitrary extensions', async () => {
+		await r.load(`/`);
+
+
+		assert.equal(
+			await r.text('h1'),
+			'Great success!'
+		);
+	});
+
+	it('works with other arbitrary extensions', async () => {
+		await r.load(`/const`);
+
+		assert.equal(
+			await r.text('h1'),
+			'Tremendous!'
+		);
+
+		await r.load(`/a`);
+
+		assert.equal(
+			await r.text('h1'),
+			'a'
+		);
+
+		await r.load(`/test-slug`);
+
+		assert.equal(
+			await r.text('h1'),
+			'TEST-SLUG'
+		);
+
+		await r.load(`/unsafe-replacement`);
+
+		assert.equal(
+			await r.text('h1'),
+			'Bazooom!'
+		);
+	});
+
+	
+});