completed the todo tests

Author: djebsoft

Sprint-2/implement/contains.test.js

@@ -20,16 +20,31 @@ as the object doesn't contains a key of 'c'
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("given an empty object, returns false", () => {
+  expect(contains({}, "x")).toEqual(false);
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("given an object with properties, returns true when passed to contains with an existing property name", () => {
+  expect(
+    contains({ gitName: "djebsoft", position: "cyf trainee" }, "gitName")
+  ).toEqual(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("given an object with properties, returns false when passed to contains with a non-existent property name", () => {
+  expect(
+    contains({ gitName: "djebsoft", position: "cyf trainee" }, "age")
+  ).toEqual(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("given invalid parameters, returns false or throws an error", () => {
+  expect(contains(["gitName", "position"], "gitName")).toEqual(false);
+});