added tests for clientUnarydEcorator

__tests__/callFactories/callDecorators/clientUnaryDecorator.js

@@ -1,16 +1,46 @@
-const object = {};
+const clientUnaryDecorator = require("../../../lib/callFactories/callDecorators/clientUnaryDecorator");
+
+const customCall = {};
+
+const mockOn = jest.fn();
+const mockCallback = jest.fn();
 const originalCall = {
-  hello: "hello"
+  hello: "hello",
+  request: "request",
+  metadata: "metadata",
+  on: mockOn
 };
-const clientUnaryDecorator = require("../../../lib/callFactories/callDecorators/clientUnaryDecorator");
+
+clientUnaryDecorator(customCall, originalCall);
 
 describe("tests for client unary decorator", () => {
   describe("basic Tests for method assignment", () => {
+    it("should have an on", () => {
+      expect(customCall.hasOwnProperty("on")).toBeTruthy();
+    });
+
+    it("should assign the body property to be call's request", () => {
+      expect(customCall.body).toBe(originalCall.request);
+    });
+
+    it("should assign the head to be the metadata", () => {
+      expect(customCall.head).toBe(originalCall.metadata);
+    });
+  });
+
+  describe("tests for on method", () => {
     beforeEach(() => {
-      clientUnaryDecorator(object, () => {});
+      mockOn.mockClear();
+      mockCallback.mockClear();
     });
-    it("should have an on", () => {
-      expect(object.hasOwnProperty("on")).toBeTruthy();
+    it("on should accept a data string and callback", () => {
+      customCall.on("data", mockCallback);
+      expect(mockCallback.mock.calls.length).toBe(1);
+    });
+
+    it("should work without a string and just a callback", () => {
+      customCall.on(mockCallback);
+      expect(mockCallback.mock.calls.length).toBe(1);
     });
   });
 });

lib/callFactories/callDecorators/clientUnaryDecorator.js

@@ -10,6 +10,9 @@ module.exports = function clientUnaryDecorator(customCall, originalCall) {
   customCall.head = originalCall.metadata;
 
   customCall.on = function(string, callback) {
+    if (typeof string !== "function" && callback === undefined) {
+      throw new Error("Second parameter to .on must be a callback.");
+    }
     if (typeof string === "function") {
       string(this.body);
     } else {