Add type tests for @ember/renderer

type-tests/@ember/renderer-tests.ts

@@ -0,0 +1,28 @@
+import { renderSettled, renderComponent } from '@ember/renderer';
+
+import { expectTypeOf } from 'expect-type';
+
+// ------- renderSettled -------
+expectTypeOf(renderSettled()).toMatchTypeOf<Promise<void>>();
+expectTypeOf<Parameters<typeof renderSettled>>().toMatchTypeOf<never[]>();
+
+// ------- renderComponent -------
+expectTypeOf<ReturnType<typeof renderComponent>>().toEqualTypeOf<{ destroy: () => void }>();
+type Params = Parameters<typeof renderComponent>;
+expectTypeOf<Params[0]>().toBeObject();
+expectTypeOf<Params[1]>().toBeObject();
+expectTypeOf<Params[1]['into']>().toBeObject();
+expectTypeOf<Params[1]['owner']>().toEqualTypeOf<undefined | object>();
+expectTypeOf<Params[1]['env']>().toMatchTypeOf<undefined | { isInteractive?: boolean | undefined }>();
+expectTypeOf<Params[1]['args']>().toEqualTypeOf<undefined | Record<string, unknown>>();
+
+// @ts-expect-error (args are required)
+renderComponent()
+// @ts-expect-error (wrong number of args)
+renderComponent(1);
+// @ts-expect-error (first arg not an object)
+renderComponent(1, null);
+// @ts-expect-error (second arg doesn't match the options)
+renderComponent({}, null);
+// @ts-expect-error (into is not an IntoTarget (Cursor | Element | SimpleElement))
+renderComponent({}, { into: 1 });