Add test for lit-html syntax

tests/syntax-lit-html.test.js

@@ -0,0 +1,47 @@
+import { run } from './util/run'
+
+let css = String.raw
+
+test('it detects classes in lit-html templates', () => {
+  let config = {
+    content: [
+      {
+        raw: `html\`<button class="bg-blue-400 hover:bg-blue-600 text-white font-bold py-2 px-4 rounded">\${data.title}</button>\`;`,
+      },
+    ],
+    corePlugins: { preflight: false },
+    theme: {},
+    plugins: [],
+  }
+
+  return run('@tailwind utilities', config).then((result) => {
+    expect(result.css).toMatchCss(css`
+      .rounded {
+        border-radius: 0.25rem;
+      }
+      .bg-blue-400 {
+        --tw-bg-opacity: 1;
+        background-color: rgb(96 165 250 / var(--tw-bg-opacity));
+      }
+      .py-2 {
+        padding-top: 0.5rem;
+        padding-bottom: 0.5rem;
+      }
+      .px-4 {
+        padding-left: 1rem;
+        padding-right: 1rem;
+      }
+      .font-bold {
+        font-weight: 700;
+      }
+      .text-white {
+        --tw-text-opacity: 1;
+        color: rgb(255 255 255 / var(--tw-text-opacity));
+      }
+      .hover\:bg-blue-600:hover {
+        --tw-bg-opacity: 1;
+        background-color: rgb(37 99 235 / var(--tw-bg-opacity));
+      }
+    `)
+  })
+})