Updated the test system

test/pipeAsyncFunctions.test.js

@@ -0,0 +1,16 @@
+const expect = require('expect');
+const {pipeAsyncFunctions} = require('./_30s.js');
+
+test('pipeAsyncFunctions is a Function', () => {
+  expect(pipeAsyncFunctions).toBeInstanceOf(Function);
+});
+test('pipeAsyncFunctions result should be 15', () => {
+  expect(
+    pipeAsyncFunctions(
+      x => x + 1,
+      x => new Promise(resolve => setTimeout(() => resolve(x + 2), 0)),
+      x => x + 3,
+      async x => (await x) + 4
+    )(5)
+  ).resolves.toBe(15);
+});