diff --git a/Sprint-2/debug/address.js b/Sprint-2/debug/address.js
index 940a6af83..fde180d6d 100644
--- a/Sprint-2/debug/address.js
+++ b/Sprint-2/debug/address.js
@@ -12,4 +12,4 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address["houseNumber"]}`);
diff --git a/Sprint-2/debug/author.js b/Sprint-2/debug/author.js
index 8c2125977..441096d65 100644
--- a/Sprint-2/debug/author.js
+++ b/Sprint-2/debug/author.js
@@ -11,6 +11,7 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+for (const value of Object.keys(author)) {
   console.log(value);
-}
+} 
+// An object is not iterable.
\ No newline at end of file
diff --git a/Sprint-2/debug/recipe.js b/Sprint-2/debug/recipe.js
index 6cbdd22cd..9e04261cc 100644
--- a/Sprint-2/debug/recipe.js
+++ b/Sprint-2/debug/recipe.js
@@ -10,6 +10,7 @@ const recipe = {
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
+
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+  ingredients:  
+${recipe.ingredients.join('\n')}`); //\n
diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index cd779308a..9f67674ee 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,3 +1,6 @@
-function contains() {}
-
+function contains(object,property) {
+// contains({a: 1, b: 2}, 'c') // returns false
+    return object.hasOwnProperty(property);
+}
+//console.log(contains({a:1, b:2},'a'))
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 326bdb1f2..cd00eef4c 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -20,7 +20,7 @@ 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.todo("contains on empty object returns false");
 
 // Given an object with properties
 // When passed to contains with an existing property name
@@ -33,3 +33,15 @@ test.todo("contains on empty object returns false");
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+describe("contains", () => {
+    [
+        { input: [{a: 1, b: 2}, 'b'], expected: true},
+        { input: [{a: 1, b: 2}, 'c'], expected: false},
+        { input: [{},'a'], expected: false},
+        { input: [[],'a'], expected: false},
+
+    ].forEach(({input, expected}) =>
+        it(`Expected to check the object contains a particular property, for: [${input}]`,() => expect(contains(...input)).toEqual(expected))
+
+    );
+});
\ No newline at end of file
diff --git a/Sprint-2/implement/lookup.js b/Sprint-2/implement/lookup.js
index a6746e07f..06a2ba157 100644
--- a/Sprint-2/implement/lookup.js
+++ b/Sprint-2/implement/lookup.js
@@ -1,5 +1,12 @@
-function createLookup() {
+function createLookup(countryCurrencyPairs) {
   // implementation here
+  let objectLookup = {}
+  for (i = 0 ; i<  countryCurrencyPairs.length ; i++){
+    //const [country, currency] = countryCurrencyPairs[i]
+     //objectLookup[country] = currency;
+    objectLookup[countryCurrencyPairs[i][0]] = countryCurrencyPairs[i][1];
+  }
+  return objectLookup
 }
 
 module.exports = createLookup;
diff --git a/Sprint-2/implement/lookup.test.js b/Sprint-2/implement/lookup.test.js
index 547e06c5a..ff7cb699a 100644
--- a/Sprint-2/implement/lookup.test.js
+++ b/Sprint-2/implement/lookup.test.js
@@ -1,6 +1,6 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
+//test.todo("creates a country currency code lookup for multiple codes");
 
 /*
 
@@ -33,3 +33,13 @@ It should return:
    'CA': 'CAD'
  }
 */
+
+describe("createLookup", () => {
+    [
+        { input: [['US', 'USD'], ['CA', 'CAD']], expected: {'US': 'USD', 'CA': 'CAD'}},
+
+    ].forEach(({input, expected}) =>
+        it(`It should Create a lookup object of key value pairs from an array of code pairs [${input}]`,() => expect(createLookup(input)).toEqual(expected))
+
+    );
+});
diff --git a/Sprint-2/implement/querystring.js b/Sprint-2/implement/querystring.js
index 45ec4e5f3..f56f6853e 100644
--- a/Sprint-2/implement/querystring.js
+++ b/Sprint-2/implement/querystring.js
@@ -6,11 +6,11 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    //const [key, value] = pair.split("=", 2);
+     const [key, value] = [pair.slice(0,pair.indexOf('=')),pair.slice(pair.indexOf('=')+1)];
+     queryParams[key] = value;
   }
-
   return queryParams;
 }
-
+console.log(parseQueryString("a=1&b=2"))
 module.exports = parseQueryString;
diff --git a/Sprint-2/implement/querystring.test.js b/Sprint-2/implement/querystring.test.js
index 3e218b789..ca706b35d 100644
--- a/Sprint-2/implement/querystring.test.js
+++ b/Sprint-2/implement/querystring.test.js
@@ -7,6 +7,22 @@ const parseQueryString = require("./querystring.js")
 
 test("parses querystring values containing =", () => {
   expect(parseQueryString("equation=x=y+1")).toEqual({
-    "equation": "x=y+1",
+    equation: "x=y+1",
   });
 });
+
+test("parses querystring with multiple key-value pairs", () => {
+  expect(parseQueryString("a=1&b=2")).toEqual({
+    a: "1",
+    b: "2",
+  });
+});
+
+test("Handle more than 1 pair in the query string", () => {
+  expect(parseQueryString("sort=newest&color=blue")).toEqual({
+    sort: "newest",
+    color: "blue",
+  });
+});
+
+
diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index f47321812..cdf6f0d91 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -1,3 +1,19 @@
-function tally() {}
+function tally(listItems) {
+  if (typeof listItems === "string" || !Array.isArray(listItems)) return new Error("Input must be array");
+  if (listItems.length === 0) return {};
 
+  let objectItems = {};
+
+  for (const item of listItems) {
+    //objectItems[item] = (objectItems[item] || 0) + 1;
+    if (objectItems[item]) {
+        objectItems[item] += 1;
+    } else {
+        objectItems[item] = 1;
+    }
+  }
+
+  return objectItems;
+}
+console.log(tally(['a','a','a','b','c','c','a']))
 module.exports = tally;
diff --git a/Sprint-2/implement/tally.test.js b/Sprint-2/implement/tally.test.js
index 2ceffa8dd..89ba25523 100644
--- a/Sprint-2/implement/tally.test.js
+++ b/Sprint-2/implement/tally.test.js
@@ -23,7 +23,7 @@ const tally = require("./tally.js");
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+//test.todo("tally on an empty array returns an empty object");
 
 // Given an array with duplicate items
 // When passed to tally
@@ -32,3 +32,15 @@ test.todo("tally on an empty array returns an empty object");
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+describe('tally',() =>{
+    [
+        {input:['a'], expected:{ a: 1 }},
+        {input:['a', 'a', 'a'], expected:{ a: 3 }},
+        {input:['a', 'a', 'b', 'c'], expected:{ a : 2, b: 1, c: 1 }},
+        {input:[], expected:{}},
+        {input: 'String', expected: new Error("Input must be array")},
+    ].forEach(({input,expected})=>
+    it(`return an object containing the count for each unique item for [${input}]`,()=>
+    expect(tally(input)).toEqual(expected))
+);
+});
\ No newline at end of file
diff --git a/Sprint-2/interpret/invert.js b/Sprint-2/interpret/invert.js
index bb353fb1f..b25dd2755 100644
--- a/Sprint-2/interpret/invert.js
+++ b/Sprint-2/interpret/invert.js
@@ -10,20 +10,22 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
-}
-
-// a) What is the current return value when invert is called with { a : 1 }
+} 
 
+//19 a) What is the current return value when invert is called with { a : 1 }
+//      After the function invert() is called with the parameter { a : 1 }, it returns: { key : 1 }
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
-
+//      After the function invert() is called with the parameter { a: 1, b: 2 }, it returns: { key : 2 }
 // c) What is the target return value when invert is called with {a : 1, b: 2}
-
+//      After the function invert() with the parameter { a: 1, b: 2 }, the target return value is: { 1 : a , 2 : b }
 // c) What does Object.entries return? Why is it needed in this program?
-
+//      Object.entries return an Array of key-value pair arrays from obj. It is useful but not strictly necessary. 
 // d) Explain why the current return value is different from the target output
-
+//      Because in the line 13 the invertedObj.key statement is not using the value of the key variable. 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+//    Done!
+module.exports = invert;
diff --git a/Sprint-2/interpret/invert.test.js b/Sprint-2/interpret/invert.test.js
new file mode 100644
index 000000000..701a991eb
--- /dev/null
+++ b/Sprint-2/interpret/invert.test.js
@@ -0,0 +1,12 @@
+const invert = require("./invert.js");
+// E.g. invert({x : 10, y : 20}), target output: {"10": "x", "20": "y"}
+describe("invert", () =>{
+    [
+        {input:{x : 10, y : 20}, expected:{"10": "x", "20": "y"}},
+        {input:{ a : 1 }, expected:{ 1 : "a" }},
+        {input:{a : 1, b: 2}, expected:{ 1 : "a" , 2 : "b" }},
+    ].forEach(({input,expected}) =>
+        it(`return inverted key / value object, for [${input}]`,()=>
+        expect(invert(input)).toEqual(expected))
+)
+});