chore(node): add tests for preview host (#518)

* Add tests

* Format

packages/node/test/preview-host.test.js

@@ -0,0 +1,63 @@
+import assert from 'node:assert/strict';
+import { after, before, describe, it } from 'node:test';
+import nodejs from '../dist/index.js';
+import { loadFixture } from './test-utils.js';
+
+describe('Astro preview host', () => {
+	it('defaults to localhost', async () => {
+		const fixture = await loadFixture({
+			root: './fixtures/preview-headers/',
+			output: 'server',
+			adapter: nodejs({ mode: 'standalone' }),
+		});
+		await fixture.build();
+		const devPreview = await fixture.preview();
+		assert.equal(devPreview.host, 'localhost');
+		await devPreview.stop();
+	});
+
+	it('uses default when set to false', async () => {
+		const fixture = await loadFixture({
+			root: './fixtures/preview-headers/',
+			output: 'server',
+			adapter: nodejs({ mode: 'standalone' }),
+			server: {
+				host: false,
+			},
+		});
+		await fixture.build();
+		const devPreview = await fixture.preview();
+		assert.equal(devPreview.host, 'localhost');
+		await devPreview.stop();
+	});
+
+	it('sets wildcard host if set to true', async () => {
+		const fixture = await loadFixture({
+			root: './fixtures/preview-headers/',
+			output: 'server',
+			adapter: nodejs({ mode: 'standalone' }),
+			server: {
+				host: true,
+			},
+		});
+		await fixture.build();
+		const devPreview = await fixture.preview();
+		assert.equal(devPreview.host, '0.0.0.0');
+		await devPreview.stop();
+	});
+
+	it('allows setting specific host', async () => {
+		const fixture = await loadFixture({
+			root: './fixtures/preview-headers/',
+			output: 'server',
+			adapter: nodejs({ mode: 'standalone' }),
+			server: {
+				host: '127.0.0.1',
+			},
+		});
+		await fixture.build();
+		const devPreview = await fixture.preview();
+		assert.equal(devPreview.host, '127.0.0.1');
+		await devPreview.stop();
+	});
+});