Add comments to includes tests

Author: Eugenie-A

Sprint-1/refactor/includes.test.js

@@ -2,34 +2,49 @@
 
 const includes = require("./includes.js");
 
+// Given an array containing the target value
+// When passed to the includes function
+// Then it should return true
 test("returns true when target is in array", () => {
   const currentOutput = includes(["a", "b", "c", "d"], "c");
   const targetOutput = true;
 
   expect(currentOutput).toEqual(targetOutput);
 });
 
+// Given an array that does not contain the target value
+// When passed to the includes function
+// Then it should return false
 test("returns false when target not in array", () => {
   const currentOutput = includes([1, 2, 3, 4], "a");
   const targetOutput = false;
 
   expect(currentOutput).toEqual(targetOutput);
 });
 
+// Given an array where the target appears more than once
+// When passed to the includes function
+// Then it should still return true
 test("returns true when the target is in array multiple times", () => {
   const currentOutput = includes([1, 2, 2, 3], 2);
   const targetOutput = true;
 
   expect(currentOutput).toEqual(targetOutput);
 });
 
+// Given an empty array
+// When passed to the includes function
+// Then it should return false
 test("returns false for empty array", () => {
   const currentOutput = includes([]);
   const targetOutput = false;
 
   expect(currentOutput).toEqual(targetOutput);
 });
 
+// Given an array containing null as an element
+// When passed to the includes function with null as the target
+// Then it should return true
 test("searches for null", () => {
   const currentOutput = includes(["b", "z", null, "a"], null);
   const targetOutput = true;