test: improve coverage

packages/runtime-dom/__tests__/helpers/useCssModule.spec.ts

@@ -0,0 +1,55 @@
+import { render, h, nodeOps } from '@vue/runtime-test'
+import { useCssModule } from '../../src/helpers/useCssModule'
+import { mockWarn } from '@vue/shared'
+
+describe('useCssModule', () => {
+  mockWarn()
+
+  function mountWithModule(modules: any, name?: string) {
+    let res
+    render(
+      h({
+        render() {},
+        __cssModules: modules,
+        setup() {
+          res = useCssModule(name)
+        }
+      }),
+      nodeOps.createElement('div')
+    )
+    return res
+  }
+
+  test('basic usage', () => {
+    const modules = {
+      $style: {
+        red: 'red'
+      }
+    }
+    expect(mountWithModule(modules)).toMatchObject(modules.$style)
+  })
+
+  test('basic usage', () => {
+    const modules = {
+      foo: {
+        red: 'red'
+      }
+    }
+    expect(mountWithModule(modules, 'foo')).toMatchObject(modules.foo)
+  })
+
+  test('warn out of setup usage', () => {
+    useCssModule()
+    expect('must be called inside setup').toHaveBeenWarned()
+  })
+
+  test('warn missing injection', () => {
+    mountWithModule(undefined)
+    expect('instance does not have CSS modules').toHaveBeenWarned()
+  })
+
+  test('warn missing injection', () => {
+    mountWithModule({ $style: { red: 'red' } }, 'foo')
+    expect('instance does not have CSS module named "foo"').toHaveBeenWarned()
+  })
+})