Manage spys/matchers/custom equalities for beforeAll

- Refactor expectations to take list of matchers
- Add spyRegistry to manage runnables' spies
- Add clone util

[#66789174]

spec/core/SpyRegistrySpec.js

@@ -0,0 +1,55 @@
+describe("SpyRegistry", function() {
+  describe("#spyOn", function() {
+    it("checks for the existence of the object", function() {
+      var spyRegistry = new j$.SpyRegistry();
+      expect(function() {
+        spyRegistry.spyOn(void 0, 'pants');
+      }).toThrowError(/could not find an object/);
+    });
+
+    it("checks for the existence of the method", function() {
+      var spyRegistry = new j$.SpyRegistry(),
+        subject = {};
+
+      expect(function() {
+        spyRegistry.spyOn(subject, 'pants');
+      }).toThrowError(/method does not exist/);
+    });
+
+    it("checks if it has already been spied upon", function() {
+      var spies = [],
+        spyRegistry = new j$.SpyRegistry({currentSpies: function() { return spies; }}),
+        subject = { spiedFunc: function() {} };
+
+      spyRegistry.spyOn(subject, 'spiedFunc');
+
+      expect(function() {
+        spyRegistry.spyOn(subject, 'spiedFunc');
+      }).toThrowError(/has already been spied upon/);
+    });
+
+    it("overrides the method on the object and returns the spy", function() {
+      var originalFunctionWasCalled = false,
+        spyRegistry = new j$.SpyRegistry(),
+        subject = { spiedFunc: function() { originalFunctionWasCalled = true; } };
+
+      var spy = spyRegistry.spyOn(subject, 'spiedFunc');
+
+      expect(subject.spiedFunc).toEqual(spy);
+    });
+  });
+
+  describe("#clearSpies", function() {
+    it("restores the original functions on the spied-upon objects", function() {
+      var spies = [],
+        spyRegistry = new j$.SpyRegistry({currentSpies: function() { return spies; }}),
+        originalFunction = function() {},
+        subject = { spiedFunc: originalFunction };
+
+      spyRegistry.spyOn(subject, 'spiedFunc');
+      spyRegistry.clearSpies();
+
+      expect(subject.spiedFunc).toBe(originalFunction);
+    });
+  });
+});