fix(vitest): correctly override api with --no-api flag (#5386)

examples/playwright/test/basic.test.ts

@@ -20,9 +20,10 @@ describe.runIf(process.platform !== 'win32')('basic', async () => {
   })
 
   afterAll(async () => {
-    await browser.close()
+    // hook timed out and we already have another error
+    await browser?.close()
     await new Promise<void>((resolve, reject) => {
-      server.httpServer.close(error => error ? reject(error) : resolve())
+      server?.httpServer.close(error => error ? reject(error) : resolve())
     })
   })
 

packages/vitest/src/node/plugins/index.ts

@@ -45,8 +45,8 @@ export async function VitestPlugin(options: UserConfig = {}, ctx = new Vitest('t
         const testConfig = deepMerge(
           {} as UserConfig,
           configDefaults,
-          options,
           removeUndefinedValues(viteConfig.test ?? {}),
+          options,
         )
         testConfig.api = resolveApiServerConfig(testConfig)
 

test/config/test/resolution.test.ts

@@ -235,3 +235,31 @@ describe('correctly defines inline and noExternal flags', async () => {
     ])
   })
 })
+
+describe('correctly defines api flag', () => {
+  it('CLI overrides disabling api', async () => {
+    const c = await vitest({ api: false }, {
+      api: {
+        port: 1234,
+      },
+      watch: true,
+    })
+    expect(c.server.config.server.middlewareMode).toBe(true)
+    expect(c.config.api).toEqual({
+      middlewareMode: true,
+    })
+  })
+
+  it('CLI overrides inlined value', async () => {
+    const c = await vitest({ api: { port: 4321 } }, {
+      api: {
+        port: 1234,
+      },
+      watch: true,
+    })
+    expect(c.server.config.server.port).toBe(4321)
+    expect(c.config.api).toEqual({
+      port: 4321,
+    })
+  })
+})