diff --git a/vite-build-config.test.ts b/vite-build-config.test.ts
new file mode 100644
index 0000000..5c809a5
--- /dev/null
+++ b/vite-build-config.test.ts
@@ -0,0 +1,79 @@
+import path from 'node:path'
+import { describe, expect, it } from 'vitest'
+
+import viteConfig from './vite.config'
+
+type ViteConfigFactory = (env: {
+    mode: string
+    command: 'build' | 'serve'
+}) => unknown
+
+async function resolveConfig(
+    mode: string,
+    command: 'build' | 'serve' = 'build'
+) {
+    const config = (viteConfig as ViteConfigFactory)({ mode, command })
+    return (await Promise.resolve(config)) as Record<string, any>
+}
+
+describe('vite config', () => {
+    it('discovers interface pages and keeps the client build output stable', async () => {
+        const config = await resolveConfig('client')
+
+        expect(config.build?.rollupOptions?.input).toEqual({
+            template: path.join(
+                'plugins',
+                'interface',
+                'pages',
+                'template',
+                'index.tsx'
+            ),
+        })
+        expect(config.build?.outDir).toBe('./public')
+        expect(config.build?.copyPublicDir).toBe(true)
+        expect(config.build?.emptyOutDir).toBe(false)
+        expect(config.build?.manifest).toBe(true)
+        expect(config.publicDir).toBe('./plugins/interface/public')
+        expect(config.resolve?.alias?.['@interface']).toBe(
+            path.resolve(process.cwd(), './plugins/interface')
+        )
+
+        const output = config.build?.rollupOptions?.output
+        expect(output.entryFileNames).toBe('assets/[name].[hash].js')
+        expect(output.chunkFileNames).toBe('assets/[name].[hash].js')
+        expect(output.assetFileNames).toBe('assets/[name].[hash][extname]')
+        expect(output.manualChunks.vendor).toEqual([
+            'hono/jsx',
+            'hono/jsx/dom/client',
+        ])
+        expect(output.manualChunks.components).toEqual(
+            expect.arrayContaining([
+                './plugins/interface/components/button/Button',
+                './plugins/interface/components/input/Input',
+                './plugins/interface/components/card',
+                './plugins/interface/components/avatar',
+            ])
+        )
+    })
+
+    it('keeps the worker build pointed at the Cloudflare entrypoint', async () => {
+        const config = await resolveConfig('development', 'serve')
+
+        expect(config.assetsInclude).toEqual(['**/*.sql'])
+        expect(config.server).toMatchObject({ port: 8787 })
+        expect(config.build?.rollupOptions?.external).toEqual([
+            'cloudflare:workers',
+        ])
+
+        const pluginNames = config.plugins
+            .map((plugin: { name?: string } | null | undefined) => plugin?.name)
+            .filter(Boolean)
+
+        expect(pluginNames).toEqual(
+            expect.arrayContaining([
+                '@hono/vite-dev-server',
+                '@hono/vite-build/cloudflare-workers',
+            ])
+        )
+    })
+})