Add tests for the CSS language server

Author: thecrypticace

packages/tailwindcss-language-server/src/language/css-server.ts

@@ -40,6 +40,11 @@ export class CssServer {
     const stylesheets = getLanguageModelCache<Stylesheet>(10, 60, (document) =>
       cssLanguageService.parseStylesheet(document),
     )
+    documents.onDidOpen(({ document }) => {
+      connection.sendNotification('@/tailwindCSS/documentReady', {
+        uri: document.uri,
+      })
+    })
     documents.onDidClose(({ document }) => {
       stylesheets.onDocumentRemoved(document)
     })

packages/tailwindcss-language-server/tests/css/css-server.test.ts

@@ -0,0 +1,33 @@
+import { expect } from 'vitest'
+import { css, defineTest } from '../../src/testing'
+import { createClient } from '../utils/client'
+
+defineTest({
+  name: 'css language handles custom-variant at-rule',
+  fs: {
+    //
+  },
+  prepare: async ({ root }) => ({
+    client: await createClient({
+      server: 'css',
+      root,
+    }),
+  }),
+  handle: async ({ client }) => {
+    let doc = await client.open({
+      lang: 'tailwindcss',
+      name: 'file-1.css',
+      text: css`
+        @import 'tailwindcss';
+        @custom-variant foo (&:hover);
+        @custom-variant bar {
+          &:hover {
+            @slot;
+          }
+        }
+      `,
+    })
+
+    expect(await doc.diagnostics()).toEqual([])
+  },
+})

packages/tailwindcss-language-server/tests/utils/connection.ts

@@ -3,6 +3,7 @@ import { createConnection } from 'vscode-languageserver/node'
 import type { ProtocolConnection } from 'vscode-languageclient/node'
 import { Duplex, type Readable, type Writable } from 'node:stream'
 import { TW } from '../../src/tw'
+import { CssServer } from '../../src/language/css-server'
 
 class TestStream extends Duplex {
   _write(chunk: string, _encoding: string, done: () => void) {
@@ -18,6 +19,10 @@ const SERVERS = {
     ServerClass: TW,
     binaryPath: './bin/tailwindcss-language-server',
   },
+  css: {
+    ServerClass: CssServer,
+    binaryPath: './bin/css-language-server',
+  },
 }
 
 export interface ConnectOptions {