add more tests

cli/types/cypress.d.ts

@@ -3067,8 +3067,7 @@ declare namespace Cypress {
   type DevServerFn<ComponentDevServerOpts = any> = (cypressDevServerConfig: DevServerConfig, devServerConfig: ComponentDevServerOpts) => ResolvedDevServerConfig | Promise<ResolvedDevServerConfig>
 
   type ConfigHandler<T> = T
-    | ((baseConfig: T) => T)
-    | ((baseConfig: T) => Promise<T>)
+    | (() => T | Promise<T>)
 
   type DevServerConfigOptions = {
     bundler: 'webpack'

npm/vite-dev-server/src/devServer.ts

@@ -7,9 +7,7 @@ const debug = debugFn('cypress:vite-dev-server:devServer')
 
 const ALL_FRAMEWORKS = ['react', 'vue'] as const
 
-type ConfigHandler = UserConfig
-| ((baseConfig: InlineConfig) => Promise<UserConfig>)
-| ((baseConfig: InlineConfig) => UserConfig)
+type ConfigHandler = UserConfig | (() => UserConfig | Promise<UserConfig>)
 
 export type ViteDevServerConfig = {
   specs: Cypress.Spec[]

npm/vite-dev-server/src/resolveConfig.ts

@@ -93,7 +93,7 @@ export const createViteDevServerConfig = async (config: ViteDevServerConfig, vit
   let resolvedOverrides: UserConfig = {}
 
   if (typeof viteOverrides === 'function') {
-    resolvedOverrides = await viteOverrides(viteBaseConfig)
+    resolvedOverrides = await viteOverrides()
   } else if (typeof viteOverrides === 'object') {
     resolvedOverrides = viteOverrides
   }

npm/vite-dev-server/test/resolveConfig.spec.ts

@@ -1,10 +1,14 @@
-import { expect } from 'chai'
+import Chai, { expect } from 'chai'
 import { EventEmitter } from 'events'
 import * as vite from 'vite'
 import { scaffoldSystemTestProject } from './test-helpers/scaffoldProject'
 import { createViteDevServerConfig } from '../src/resolveConfig'
+import sinon from 'sinon'
+import SinonChai from 'sinon-chai'
 import type { ViteDevServerConfig } from '../src/devServer'
 
+Chai.use(SinonChai)
+
 const getViteDevServerConfig = (projectRoot: string) => {
   return {
     specs: [],
@@ -21,6 +25,29 @@ const getViteDevServerConfig = (projectRoot: string) => {
 describe('resolveConfig', function () {
   this.timeout(1000 * 60)
 
+  it('calls viteConfig if it is a function, passing in the base config', async () => {
+    const viteConfigFn = sinon.spy(async () => {
+      return {
+        server: {
+          fs: {
+            allow: ['some/other/file'],
+          },
+        },
+      }
+    })
+
+    const projectRoot = await scaffoldSystemTestProject('vite-inspect')
+    const viteDevServerConfig = {
+      ...getViteDevServerConfig(projectRoot),
+      viteConfig: viteConfigFn,
+    }
+
+    const viteConfig = await createViteDevServerConfig(viteDevServerConfig, vite)
+
+    expect(viteConfigFn).to.be.called
+    expect(viteConfig.server.fs.allow).to.include('some/other/file')
+  })
+
   context('inspect plugin', () => {
     it('should not include inspect plugin by default', async () => {
       const projectRoot = await scaffoldSystemTestProject('vite-inspect')

npm/webpack-dev-server/src/devServer.ts

@@ -27,9 +27,9 @@ type FrameworkConfig = {
   }
 }
 
-export type ConfigHandler = Partial<Configuration>
-| ((baseConfig: Configuration) => Promise<Configuration>)
-| ((baseConfig: Configuration) => Configuration)
+export type ConfigHandler =
+  Partial<Configuration>
+  | (() => Partial<Configuration> | Promise<Partial<Configuration>>)
 
 export type WebpackDevServerConfig = {
   specs: Cypress.Spec[]

npm/webpack-dev-server/src/makeWebpackConfig.ts

@@ -126,7 +126,7 @@ export async function makeWebpackConfig (
   }
 
   userWebpackConfig = typeof userWebpackConfig === 'function'
-    ? await userWebpackConfig(frameworkWebpackConfig)
+    ? await userWebpackConfig()
     : userWebpackConfig
 
   const userAndFrameworkWebpackConfig = modifyWebpackConfigForCypress(

npm/webpack-dev-server/test/makeWebpackConfig.spec.ts

@@ -1,10 +1,15 @@
-import { expect } from 'chai'
+import Chai, { expect } from 'chai'
 import EventEmitter from 'events'
 import snapshot from 'snap-shot-it'
+import { IgnorePlugin } from 'webpack'
 import { WebpackDevServerConfig } from '../src/devServer'
 import { sourceDefaultWebpackDependencies } from '../src/helpers/sourceRelativeWebpackModules'
 import { CYPRESS_WEBPACK_ENTRYPOINT, makeWebpackConfig } from '../src/makeWebpackConfig'
 import { createModuleMatrixResult } from './test-helpers/createModuleMatrixResult'
+import sinon from 'sinon'
+import SinonChai from 'sinon-chai'
+
+Chai.use(SinonChai)
 
 describe('makeWebpackConfig', () => {
   it('ignores userland webpack `output.publicPath` and `devServer.overlay` with webpack-dev-server v3', async () => {
@@ -136,4 +141,45 @@ describe('makeWebpackConfig', () => {
       'cypress-entry': CYPRESS_WEBPACK_ENTRYPOINT,
     })
   })
+
+  it('calls webpackConfig if it is a function, passing in the base config', async () => {
+    const testPlugin = new IgnorePlugin({
+      contextRegExp: /aaa/,
+      resourceRegExp: /bbb/,
+    })
+
+    const modifyConfig = sinon.spy(async () => {
+      return {
+        plugins: [testPlugin],
+      }
+    })
+
+    const devServerConfig: WebpackDevServerConfig = {
+      specs: [],
+      cypressConfig: {
+        isTextTerminal: false,
+        projectRoot: '.',
+        supportFile: '/support.js',
+        devServerPublicPathRoute: '/test-public-path', // This will be overridden by makeWebpackConfig.ts
+      } as Cypress.PluginConfigOptions,
+      webpackConfig: modifyConfig,
+      devServerEvents: new EventEmitter(),
+    }
+
+    const actual = await makeWebpackConfig({
+      devServerConfig,
+      sourceWebpackModulesResult: createModuleMatrixResult({
+        webpack: 4,
+        webpackDevServer: 4,
+      }),
+    })
+
+    expect(actual.plugins.length).to.eq(3)
+    expect(modifyConfig).to.have.been.called
+    // merged plugins get added at the top of the chain by default
+    // should be merged, not overriding existing plugins
+    expect(actual.plugins[0].constructor.name).to.eq('IgnorePlugin')
+    expect(actual.plugins[1].constructor.name).to.eq('HtmlWebpackPlugin')
+    expect(actual.plugins[2].constructor.name).to.eq('CypressCTWebpackPlugin')
+  })
 })