test(integration-karma): test bare decorator APIs (#4434)

Co-authored-by: Will Harney <[email protected]>

packages/@lwc/integration-karma/test/api/decorators/facade.js

@@ -0,0 +1 @@
+export { api, track, wire } from 'lwc';

packages/@lwc/integration-karma/test/api/decorators/index.spec.js

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+// This facade is used because the compiler will throw `IS_NOT_DECORATOR` if it detects a decorator
+// imported from 'lwc' used as a non-decorator. But it can't detect when those same functions are
+// re-exported from a facade!
+import { api, track, wire } from './facade.js';
+
+describe('decorator APIs used as non-decorators', () => {
+ it('api() throws error', () => {
+ expect(api).toThrowError(
+ process.env.NODE_ENV === 'production'
+ ? ''
+ : /@api decorator can only be used as a decorator function/
+ );
+ });
+
+ it('wire() throws error', () => {
+ expect(wire).toThrowError(
+ process.env.NODE_ENV === 'production'
+ ? ''
+ : /@wire\(adapter, config\?\) may only be used as a decorator/
+ );
+ });
+
+ it('track() throws error when passed arguments.length !== 1', () => {
+ const funcs = [
+ () => track(),
+ () => track('foo', 'bar'),
+ () => track('foo', undefined),
+ () => track('foo', 'bar', 'baz'),
+ () => track('foo', undefined, 'baz'),
+ ];
+
+ for (const func of funcs) {
+ expect(func).toThrowError(
+ process.env.NODE_ENV === 'production'
+ ? ''
+ : /@track decorator can only be used with one argument to return a trackable object, or as a decorator function/
+ );
+ }
+ });
+
+ it('track() returns reactive proxy when passed exactly 1 arg', () => {
+ const obj = { foo: 'bar' };
+ const proxy = track(obj);
+
+ expect(proxy).toEqual(obj);
+ expect(proxy).not.toBe(obj);
+ });
+});