From bd388e49496e0128b08241df18aa534e864259c6 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 10:22:39 +0000
Subject: [PATCH 01/24] Implement input validation and error handling in
 calculateMedian function

---
 Sprint-1/fix/median.js | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index 5c5b796e1..2f00b07ba 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -2,13 +2,39 @@
 // Start by running the tests for this function
 // If you're in the Sprint-1 directory, you can run `npm test -- fix` to run the tests in the fix directory
 
+
+
 // Hint: Please consider scenarios when 'list' isn't an array, is empty,
 // or contains values that aren't numbers (the function is expected to throw - see the tests).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  // 1. Check if 'list' is a valid array and not null/undefined
+  if (!Array.isArray(list)) {
+    throw new Error("calculateMedian requires an array of numbers");
+  }
+
+  // 2. Check if the array is empty
+  if (list.length === 0) {
+    throw new Error("calculateMedian requires a non-empty array");
+  }
+
+  // 3. Check if every item in the array is a valid number (no strings, null, undefined, etc.)
+  for (const item of list) {
+    if (typeof item !== "number" || Number.isNaN(item)) {
+      throw new Error("calculateMedian requires an array of numbers");
+    }
+  }
+
+  // 4. Create a sorted copy of the array so we don't mutate the original input
+  const sorted = [...list].sort((a, b) => a - b);
+  const mid = Math.floor(sorted.length / 2);
+
+  // 5. Calculate median for odd vs even length arrays
+  if (sorted.length % 2 !== 0) {
+    return sorted[mid];
+  } else {
+    return (sorted[mid - 1] + sorted[mid]) / 2;
+  }
 }
 
-module.exports = calculateMedian;
+module.exports = calculateMedian;
\ No newline at end of file

From dbf4e214659dc2d8f464ad3cc8f6c394b68fc74f Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 11:15:59 +0000
Subject: [PATCH 02/24] Add a blank line for better readability in dedupe test
 file

---
 Sprint-1/implement/dedupe.test.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index d7c8e3d8e..8182af7ee 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -18,6 +18,7 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // Then it should return an empty array
 test.todo("given an empty array, it returns an empty array");
 
+
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array

From 1e13f783af03204b64404869da4df9d725974552 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 11:36:42 +0000
Subject: [PATCH 03/24] Add tests for dedupe function to validate behavior with
 empty and unique arrays

---
 Sprint-1/implement/dedupe.test.js | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index 8182af7ee..73fd8841e 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -18,12 +18,33 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // Then it should return an empty array
 test.todo("given an empty array, it returns an empty array");
 
+it("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+})
+
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
+test.todo("given an array, it returns a copy of the original array");
+
+it("given an array, it returns a copy of the original array", () => {
+const input = [1,2,3];
+const result = dedupe(input)
+
+  expect(result).toEqual([1,2,3]);
+  expect(result).not.toBe(input);
+});
 
 // Given an array of strings or numbers
 // When passed to the dedupe function
 // Then it should return a new array with duplicates removed while preserving the 
 // first occurrence of each element from the original array.
+
+test.todo("given an array, it returns a duplicate while preserving the first occurrence of each element from the original array");
+
+it("given an array, it removes duplicates while preserving the first occurrence of elements", () => {
+expect(dedupe(['a', 'a', 'a', 'b', 'b', 'c'])).toEqual(['a', 'b', 'c']); 
+expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]); 
+ expect(dedupe([ 1, 2, 1])).toEqual([1, 2]); 
+});

From d940b04ee6b274395dca887d27a11df69cb57241 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 11:38:35 +0000
Subject: [PATCH 04/24] Implement dedupe function to remove duplicate values
 from an array

---
 Sprint-1/implement/dedupe.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..20f2603e0 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,4 @@
-function dedupe() {}
+function dedupe(arr) {
+  return [... new Set(arr)]
+}
+module.exports = dedupe;

From 26c125ec3cd77d3a0d91d3da1279c1c50f7d15df Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 11:54:51 +0000
Subject: [PATCH 05/24] Implement describeMedian function to calculate and
 return the median value, with error handling for invalid inputs

---
 Sprint-1/implement/describe-median.js | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Sprint-1/implement/describe-median.js b/Sprint-1/implement/describe-median.js
index 3381cfc0a..da67bbd60 100644
--- a/Sprint-1/implement/describe-median.js
+++ b/Sprint-1/implement/describe-median.js
@@ -20,6 +20,13 @@ function calculateMedian(list) {
 }
 
 // Implement this function. See describe-median.test.js for the acceptance criteria.
-function describeMedian(list) {}
+function describeMedian(list) {
+  try {
+    const median = calculateMedian(list);
+    return `The median is ${median}`;
+  } catch {
+    return `Could not calculate a median: ${error.message}`;
+  }
+}
 
 module.exports = describeMedian;

From 96de1955913b9725020c086d5c669346ae74c774 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 11:55:04 +0000
Subject: [PATCH 06/24] Add tests for describeMedian function to validate
 median calculation and error handling

---
 Sprint-1/implement/describe-median.test.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Sprint-1/implement/describe-median.test.js b/Sprint-1/implement/describe-median.test.js
index e7d18a264..5fad3d748 100644
--- a/Sprint-1/implement/describe-median.test.js
+++ b/Sprint-1/implement/describe-median.test.js
@@ -23,10 +23,19 @@ const describeMedian = require("./describe-median.js");
 // Delete this test.todo and replace it with a test.
 test.todo('given [1, 2, 3], returns "The median is 2"');
 
+describe("describeMedian", () => {
+  it("given [1, 2, 3], returns {The median is 2}", () => {
+    expect(describeMedian([1, 2, 3])).toEqual("The median is 2");
+  })
+})
+
+
 // Given an empty array
 // When passed to describeMedian
 // Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
 
+
+
 // Given something that isn't an array of numbers, e.g. "banana"
 // When passed to describeMedian
 // Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"

From 9ec2074c8a218894b3aa373640eff967a0449656 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 11:57:17 +0000
Subject: [PATCH 07/24] Add test case for describeMedian to handle empty array
 input

---
 Sprint-1/implement/describe-median.test.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Sprint-1/implement/describe-median.test.js b/Sprint-1/implement/describe-median.test.js
index 5fad3d748..12b4254bf 100644
--- a/Sprint-1/implement/describe-median.test.js
+++ b/Sprint-1/implement/describe-median.test.js
@@ -34,7 +34,13 @@ describe("describeMedian", () => {
 // When passed to describeMedian
 // Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
 
+test.todo('given [1, 2, 3], returns "The median is 2"');
 
+describe("describeMedian", () => {
+  it("given [], returns Could not calculate a median : calculateMedian requires a non-empty array", () => {
+    expect(describeMedian([])).toEqual("calculateMedian requires a non-empty array");
+  })
+})
 
 // Given something that isn't an array of numbers, e.g. "banana"
 // When passed to describeMedian

From 547e68b658c544c082df3080567948ed6b34a6af Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 12:00:58 +0000
Subject: [PATCH 08/24] Add test case for describeMedian to handle non-array
 input

---
 Sprint-1/implement/describe-median.test.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Sprint-1/implement/describe-median.test.js b/Sprint-1/implement/describe-median.test.js
index 12b4254bf..a1971366c 100644
--- a/Sprint-1/implement/describe-median.test.js
+++ b/Sprint-1/implement/describe-median.test.js
@@ -45,3 +45,10 @@ describe("describeMedian", () => {
 // Given something that isn't an array of numbers, e.g. "banana"
 // When passed to describeMedian
 // Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"
+test.todo('given [1, 2, 3], returns "The median is 2"');
+
+describe("describeMedian", () => {
+  it("given something is not an array, returns Could not calculate a median : calculateMedian requires an array of numbers", () => {
+    expect(describeMedian([])).toEqual("calculateMedian requires an array of numbers");
+  })
+})
\ No newline at end of file

From fe34b63a57adcc8bb93d3ba4dcb302de92fb4341 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 12:02:54 +0000
Subject: [PATCH 09/24] Refactor describeMedian tests to remove todos and
 ensure correct error handling for empty arrays

---
 Sprint-1/implement/describe-median.test.js | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/Sprint-1/implement/describe-median.test.js b/Sprint-1/implement/describe-median.test.js
index a1971366c..37d36d85c 100644
--- a/Sprint-1/implement/describe-median.test.js
+++ b/Sprint-1/implement/describe-median.test.js
@@ -26,22 +26,20 @@ test.todo('given [1, 2, 3], returns "The median is 2"');
 describe("describeMedian", () => {
   it("given [1, 2, 3], returns {The median is 2}", () => {
     expect(describeMedian([1, 2, 3])).toEqual("The median is 2");
-  })
-})
+  });
+
+  it("given an empty array, returns the correct error message", () => {
+    expect(describeMedian([])).toEqual(
+      "Could not calculate a median: calculateMedian requires a non-empty array"
+    );
+  });
+});
 
 
 // Given an empty array
 // When passed to describeMedian
 // Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
 
-test.todo('given [1, 2, 3], returns "The median is 2"');
-
-describe("describeMedian", () => {
-  it("given [], returns Could not calculate a median : calculateMedian requires a non-empty array", () => {
-    expect(describeMedian([])).toEqual("calculateMedian requires a non-empty array");
-  })
-})
-
 // Given something that isn't an array of numbers, e.g. "banana"
 // When passed to describeMedian
 // Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"

From 411ad3fa8329644d9ef427ad43eff2be5d18200f Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 12:03:57 +0000
Subject: [PATCH 10/24] Refactor describeMedian tests to improve clarity and
 organization

---
 Sprint-1/implement/describe-median.test.js | 29 ++++++++++------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/Sprint-1/implement/describe-median.test.js b/Sprint-1/implement/describe-median.test.js
index 37d36d85c..abdce10b8 100644
--- a/Sprint-1/implement/describe-median.test.js
+++ b/Sprint-1/implement/describe-median.test.js
@@ -28,25 +28,22 @@ describe("describeMedian", () => {
     expect(describeMedian([1, 2, 3])).toEqual("The median is 2");
   });
 
+  // Given an empty array
+  // When passed to describeMedian
+  // Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
+
   it("given an empty array, returns the correct error message", () => {
     expect(describeMedian([])).toEqual(
       "Could not calculate a median: calculateMedian requires a non-empty array"
     );
   });
-});
-
-
-// Given an empty array
-// When passed to describeMedian
-// Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
-
-// Given something that isn't an array of numbers, e.g. "banana"
-// When passed to describeMedian
-// Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"
-test.todo('given [1, 2, 3], returns "The median is 2"');
 
-describe("describeMedian", () => {
-  it("given something is not an array, returns Could not calculate a median : calculateMedian requires an array of numbers", () => {
-    expect(describeMedian([])).toEqual("calculateMedian requires an array of numbers");
-  })
-})
\ No newline at end of file
+  // Given something that isn't an array of numbers, e.g. "banana"
+  // When passed to describeMedian
+  // Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"
+  it("given something that isn't an array, returns the correct error message", () => {
+    expect(describeMedian("banana")).toEqual(
+      "Could not calculate a median: calculateMedian requires an array of numbers"
+    );
+  });
+});

From 1c76aa49f538fbb95a39356f2db15c172c22072b Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 12:06:37 +0000
Subject: [PATCH 11/24] Improve error handling in describeMedian by capturing
 error parameter

---
 Sprint-1/implement/describe-median.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sprint-1/implement/describe-median.js b/Sprint-1/implement/describe-median.js
index da67bbd60..23764c40a 100644
--- a/Sprint-1/implement/describe-median.js
+++ b/Sprint-1/implement/describe-median.js
@@ -24,7 +24,7 @@ function describeMedian(list) {
   try {
     const median = calculateMedian(list);
     return `The median is ${median}`;
-  } catch {
+  } catch(error) {
     return `Could not calculate a median: ${error.message}`;
   }
 }

From 34fbfe574b0d1ae3d24fe090c1453752e2dbe08e Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 12:14:00 +0000
Subject: [PATCH 12/24] Implement findMax function with input validation and
 error handling

---
 Sprint-1/implement/max.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..ea0b63558 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,23 @@
 function findMax(elements) {
+  // 1. Check if input is a valid array and not null/undefined
+  if (!Array.isArray(elements)) {
+    throw new Error("findMax requires an array of numbers");
+  }
+
+  // 2. Handle empty array edge case per requirements
+  if (elements.length === 0) {
+    return -Infinity;
+  }
+
+  // 3. Validate that every item in the array is strictly a number (no strings, null, etc.)
+  for (const item of elements) {
+    if (typeof item !== "number" || Number.isNaN(item)) {
+      throw new Error("findMax requires an array of numbers");
+    }
+  }
+
+  // 4. Return the maximum number using Math.max
+  return Math.max(...elements);
 }
 
 module.exports = findMax;

From 866d1d04ca07a56ff273fa83f64b747b6deace1b Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Sun, 1 Nov 2026 12:14:09 +0000
Subject: [PATCH 13/24] Add tests for findMax function to cover various
 scenarios including empty arrays, negative numbers, decimals, and non-array
 inputs

---
 Sprint-1/implement/max.test.js | 71 +++++++++++++++++++++++++---------
 1 file changed, 52 insertions(+), 19 deletions(-)

diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index ff3fbb5e5..8b136e896 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -16,28 +16,61 @@ const findMax = require("./max.js");
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+describe("findMax", () => {
+  it("given an empty array, returns -Infinity", () => {
+    expect(findMax([])).toEqual(-Infinity);
+  });
 
-// Given an array with one number
-// When passed to the max function
-// Then it should return that number
+  // Given an array with one number
+  // When passed to the max function
+  // Then it should return that number
 
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
+  it("given an array with one number, returns that number", () => {
+    expect(findMax([42])).toEqual(42);
+  });
 
-// Given an array with just negative numbers
-// When passed to the max function
-// Then it should return the closest one to zero
+  // Given an array with both positive and negative numbers
+  // When passed to the max function
+  // Then it should return the largest number overall
+  it("given an array with both positive and negative numbers, returns the largest number overall", () => {
+    expect(findMax([30, -50, 10, 40, -5])).toEqual(40);
+  });
 
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
+  // Given an array with just negative numbers
+  // When passed to the max function
+  // Then it should return the closest one to zero
+  it("given an array with just negative numbers, returns the closest one to zero", () => {
+    expect(findMax([-10, -3, -50, -5])).toEqual(-3);
+  });
 
-// Given an array containing a value that isn't a number
-// When passed to the max function
-// Then it should throw Error("findMax requires an array of numbers")
+  // Given an array with decimal numbers
+  // When passed to the max function
+  // Then it should return the largest decimal number
+  it("given an array with decimal numbers, returns the largest decimal number", () => {
+    expect(findMax([1.5, 2.7, 2.1, 0.4])).toEqual(2.7);
+  });
 
-// Given something that isn't an array at all, such as "hey", 42 or no argument
-// When passed to the max function
-// Then it should throw Error("findMax requires an array of numbers")
+  // Given an array containing a value that isn't a number
+  // When passed to the max function
+  // Then it should throw Error("findMax requires an array of numbers")
+  it("given an array containing a value that isn't a number, throws an error", () => {
+    expect(() => findMax(["hey", 10, "hi", 60, 10])).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+  });
+
+  // Given something that isn't an array at all, such as "hey", 42 or no argument
+  // When passed to the max function
+  // Then it should throw Error("findMax requires an array of numbers")
+  it("given something that isn't an array at all, throws an error", () => {
+    expect(() => findMax("hey")).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+    expect(() => findMax(42)).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+    expect(() => findMax()).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+  });
+});

From bc3b0d2a15f56612d60a5d691f21cbb261b41ac5 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:32:01 +0000
Subject: [PATCH 14/24] Implement calculateMean function with input validation
 and error handling

---
 Sprint-1/implement/mean.js | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/Sprint-1/implement/mean.js b/Sprint-1/implement/mean.js
index 36909ea1f..b7ac32e55 100644
--- a/Sprint-1/implement/mean.js
+++ b/Sprint-1/implement/mean.js
@@ -1,3 +1,25 @@
-function calculateMean(list) {}
+function calculateMean(list) {
+  // 1. Check if input is a valid array
+  if (!Array.isArray(list)) {
+    throw new Error("calculateMean requires an array of numbers");
+  }
 
-module.exports = calculateMean;
+  // 2. Check if the array is empty
+  if (list.length === 0) {
+    throw new Error("calculateMean requires a non-empty array");
+  }
+
+  // 3. Validate that every item in the array is strictly a number
+  let sum = 0;
+  for (const item of list) {
+    if (typeof item !== "number" || Number.isNaN(item)) {
+      throw new Error("calculateMean requires an array of numbers");
+    }
+    sum += item;
+  }
+
+  // 4. Return the calculated mean
+  return sum / list.length;
+}
+
+module.exports = calculateMean;
\ No newline at end of file

From ddaa794594f6c8bbe41d853d0f64db50afff8d68 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:34:03 +0000
Subject: [PATCH 15/24] Add test for calculateMean function to validate mean
 calculation for an array of numbers

---
 Sprint-1/implement/mean.test.js | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index 847b88676..8eb65faa6 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -19,11 +19,18 @@ const calculateMean = require("./mean.js");
 
 // Acceptance criteria:
 
-// Given an array of numbers
+
+// Delete this test.todo and replace it with a test.
+describe("calculateMean", () => {
+
+  // Given an array of numbers
 // When passed to calculateMean
 // Then it should return their mean
-// Delete this test.todo and replace it with a test.
-test.todo("given [1, 2, 6], returns 3");
+
+  it("given [1, 2, 6], returns 3", () => {
+    expect(calculateMean([1, 2, 6])).toEqual(3);
+  });
+})
 
 // Given an array with a single number
 // When passed to calculateMean

From 3e45546d4884dc406d1bd70703c0678a687fd971 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:34:36 +0000
Subject: [PATCH 16/24] Add test for calculateMean function to verify single
 number input

---
 Sprint-1/implement/mean.test.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index 8eb65faa6..c391cefda 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -30,12 +30,18 @@ describe("calculateMean", () => {
   it("given [1, 2, 6], returns 3", () => {
     expect(calculateMean([1, 2, 6])).toEqual(3);
   });
-})
 
 // Given an array with a single number
 // When passed to calculateMean
 // Then it should return that number
 
+it("given an array with a single number, returns that number", () => {
+    expect(calculateMean([10])).toEqual(10);
+  });
+})
+
+
+
 // Given an array containing negative or decimal numbers
 // When passed to calculateMean
 // Then it should return the correct mean

From b1069feceae5275f026f8bb86d3a0ef0328c38b2 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:35:16 +0000
Subject: [PATCH 17/24] Add test for calculateMean function to validate mean
 calculation for negative and decimal numbers

---
 Sprint-1/implement/mean.test.js | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index c391cefda..4e966e476 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -38,14 +38,21 @@ describe("calculateMean", () => {
 it("given an array with a single number, returns that number", () => {
     expect(calculateMean([10])).toEqual(10);
   });
-})
-
-
 
 // Given an array containing negative or decimal numbers
 // When passed to calculateMean
 // Then it should return the correct mean
 
+it("given an array containing negative or decimal numbers, returns the correct mean", () => {
+    expect(calculateMean([10, -2, 6])).toEqual(4);
+    expect(calculateMean([1.5, 2.5])).toEqual(2);
+  });
+})
+
+
+
+
+
 // Given an empty array
 // When passed to calculateMean
 // Then it should throw Error("calculateMean requires a non-empty array")

From 4faa8075b6283b2dc83d57bbe6628fc055d83671 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:36:47 +0000
Subject: [PATCH 18/24] Add tests for calculateMean function to verify error
 handling for empty arrays and non-array inputs

---
 Sprint-1/implement/mean.test.js | 35 ++++++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index 4e966e476..4104f379e 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -47,20 +47,45 @@ it("given an array containing negative or decimal numbers, returns the correct m
     expect(calculateMean([10, -2, 6])).toEqual(4);
     expect(calculateMean([1.5, 2.5])).toEqual(2);
   });
-})
-
-
-
-
 
 // Given an empty array
 // When passed to calculateMean
 // Then it should throw Error("calculateMean requires a non-empty array")
 
+it("given an empty array, throws the correct error", () => {
+    expect(() => calculateMean([])).toThrow(
+      new Error("calculateMean requires a non-empty array")
+    );
+  });
+
 // Given a value that isn't an array, e.g. "banana", 42, null or {}
 // When passed to calculateMean
 // Then it should throw Error("calculateMean requires an array of numbers")
 
+it("given a value that isn't an array (string, number, null, object), throws the correct error", () => {
+    expect(() => calculateMean("banana")).toThrow(
+      new Error("calculateMean requires an array of numbers")
+    );
+    expect(() => calculateMean(42)).toThrow(
+      new Error("calculateMean requires an array of numbers")
+    );
+    expect(() => calculateMean(null)).toThrow(
+      new Error("calculateMean requires an array of numbers")
+    );
+    expect(() => calculateMean({})).toThrow(
+      new Error("calculateMean requires an array of numbers")
+    );
+  });
+})
+
+
+
+
+
+
+
+
+
 // Given no argument at all
 // When passed to calculateMean
 // Then it should throw Error("calculateMean requires an array of numbers")

From 35df2b2cd7b5c4368287aea77cc31ea9e394ec8c Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:37:24 +0000
Subject: [PATCH 19/24] Add test for calculateMean function to verify error
 handling for no arguments

---
 Sprint-1/implement/mean.test.js | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index 4104f379e..4cef205ca 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -76,6 +76,16 @@ it("given a value that isn't an array (string, number, null, object), throws the
       new Error("calculateMean requires an array of numbers")
     );
   });
+
+// Given no argument at all
+// When passed to calculateMean
+// Then it should throw Error("calculateMean requires an array of numbers")
+
+it("given no argument at all, throws the correct error", () => {
+    expect(() => calculateMean()).toThrow(
+      new Error("calculateMean requires an array of numbers")
+    );
+  });
 })
 
 
@@ -86,9 +96,7 @@ it("given a value that isn't an array (string, number, null, object), throws the
 
 
 
-// Given no argument at all
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+
 
 // Given an array containing a non-number value, e.g. [1, "2", 3]
 // When passed to calculateMean

From 9d10901f13cef7532a81eee347b8abdd0b7d016f Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:37:59 +0000
Subject: [PATCH 20/24] Add tests for calculateMean function to validate error
 handling for non-number values and no arguments

---
 Sprint-1/implement/mean.test.js | 68 +++++++++++++++------------------
 1 file changed, 31 insertions(+), 37 deletions(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index 4cef205ca..f4a54f181 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -19,50 +19,48 @@ const calculateMean = require("./mean.js");
 
 // Acceptance criteria:
 
-
 // Delete this test.todo and replace it with a test.
 describe("calculateMean", () => {
-
   // Given an array of numbers
-// When passed to calculateMean
-// Then it should return their mean
+  // When passed to calculateMean
+  // Then it should return their mean
 
   it("given [1, 2, 6], returns 3", () => {
     expect(calculateMean([1, 2, 6])).toEqual(3);
   });
 
-// Given an array with a single number
-// When passed to calculateMean
-// Then it should return that number
+  // Given an array with a single number
+  // When passed to calculateMean
+  // Then it should return that number
 
-it("given an array with a single number, returns that number", () => {
+  it("given an array with a single number, returns that number", () => {
     expect(calculateMean([10])).toEqual(10);
   });
 
-// Given an array containing negative or decimal numbers
-// When passed to calculateMean
-// Then it should return the correct mean
+  // Given an array containing negative or decimal numbers
+  // When passed to calculateMean
+  // Then it should return the correct mean
 
-it("given an array containing negative or decimal numbers, returns the correct mean", () => {
+  it("given an array containing negative or decimal numbers, returns the correct mean", () => {
     expect(calculateMean([10, -2, 6])).toEqual(4);
     expect(calculateMean([1.5, 2.5])).toEqual(2);
   });
 
-// Given an empty array
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires a non-empty array")
+  // Given an empty array
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires a non-empty array")
 
-it("given an empty array, throws the correct error", () => {
+  it("given an empty array, throws the correct error", () => {
     expect(() => calculateMean([])).toThrow(
       new Error("calculateMean requires a non-empty array")
     );
   });
 
-// Given a value that isn't an array, e.g. "banana", 42, null or {}
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+  // Given a value that isn't an array, e.g. "banana", 42, null or {}
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires an array of numbers")
 
-it("given a value that isn't an array (string, number, null, object), throws the correct error", () => {
+  it("given a value that isn't an array (string, number, null, object), throws the correct error", () => {
     expect(() => calculateMean("banana")).toThrow(
       new Error("calculateMean requires an array of numbers")
     );
@@ -77,27 +75,23 @@ it("given a value that isn't an array (string, number, null, object), throws the
     );
   });
 
-// Given no argument at all
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+  // Given no argument at all
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires an array of numbers")
 
-it("given no argument at all, throws the correct error", () => {
+  it("given no argument at all, throws the correct error", () => {
     expect(() => calculateMean()).toThrow(
       new Error("calculateMean requires an array of numbers")
     );
   });
-})
-
-
-
-
-
 
+  // Given an array containing a non-number value, e.g. [1, "2", 3]
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires an array of numbers")
 
-
-
-
-
-// Given an array containing a non-number value, e.g. [1, "2", 3]
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+  it("given an array containing a non-number value, throws the correct error", () => {
+    expect(() => calculateMean([1, "2", 3])).toThrow(
+      new Error("calculateMean requires an array of numbers")
+    );
+  });
+});

From 292c6ed21cf22168c4f008f6629ba9a71bfbe2f9 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 21:40:13 +0000
Subject: [PATCH 21/24] Update test for calculateMean function to use different
 input values for mean calculation

---
 Sprint-1/implement/mean.test.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index f4a54f181..8fd9b4bff 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -42,7 +42,7 @@ describe("calculateMean", () => {
   // Then it should return the correct mean
 
   it("given an array containing negative or decimal numbers, returns the correct mean", () => {
-    expect(calculateMean([10, -2, 6])).toEqual(4);
+    expect(calculateMean([6, -2, 8])).toEqual(4); // 6 + (-2) + 8 = 12 / 3 = 4
     expect(calculateMean([1.5, 2.5])).toEqual(2);
   });
 

From 59d9646e809d9f7813f63f8fc0c068e8ccc8edf3 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 22:00:49 +0000
Subject: [PATCH 22/24] Add sum function to calculate the total of an array,
 including input validation

---
 Sprint-1/implement/sum.js | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..b263048d7 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,25 @@
 function sum(elements) {
+  // 1. Check if input is a valid array
+  if (!Array.isArray(elements)) {
+    throw new Error("sum requires an array of numbers");
+  }
+
+  // 2. Handle empty array edge case (sum of empty array is 0)
+  if (elements.length === 0) {
+    return 0;
+  }
+
+  // 3. Validate that every item in the array is strictly a number
+  let total = 0;
+  for (const item of elements) {
+    if (typeof item !== "number" || Number.isNaN(item)) {
+      throw new Error("sum requires an array of numbers");
+    }
+    total += item;
+  }
+
+  // 4. Return the calculated sum
+  return total;
 }
 
-module.exports = sum;
+module.exports = sum;
\ No newline at end of file

From 55d75287f62baa3c3ac5f00ebe9b0146c753fd05 Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 22:04:25 +0000
Subject: [PATCH 23/24] Add tests for sum function to validate various input
 scenarios and error handling

---
 Sprint-1/implement/sum.test.js | 50 ++++++++++++++++++++++++++++++++--
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index a288e0f0a..6725eac57 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -10,27 +10,73 @@ const sum = require("./sum.js");
 
 // Acceptance Criteria:
 
+
+describe("sum", () => {
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+
+it("given an empty array, returns 0", () => {
+    expect(sum([])).toEqual(0);
+  });
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
 
+it("given an array with just one number, returns that number", () => {
+    expect(sum([42])).toEqual(42);
+  });
+
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
 
+it("given an array containing negative numbers, returns the correct total sum", () => {
+    expect(sum([10, -20, 30])).toEqual(20);
+  });
+
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
 
-// Given an array containing a value that isn't a number
+it("given an array with decimal/float numbers, returns the correct total sum", () => {
+    expect(sum([1.5, 2.5, 3.0])).toEqual(7);
+  });
+
+  // Given an array containing a value that isn't a number
 // When passed to the sum function
 // Then it should throw Error("sum requires an array of numbers")
 
+it("given an array containing a value that isn't a number, throws an error", () => {
+    expect(() => sum(["hey", 10, "hi", 60, 10])).toThrow(
+      new Error("sum requires an array of numbers")
+    );
+  });
+
 // Given something that isn't an array at all, such as "hey", 42 or no argument
 // When passed to the sum function
 // Then it should throw Error("sum requires an array of numbers")
+
+it("given something that isn't an array at all, throws an error", () => {
+    expect(() => sum("hey")).toThrow(
+      new Error("sum requires an array of numbers")
+    );
+    expect(() => sum(42)).toThrow(
+      new Error("sum requires an array of numbers")
+    );
+    expect(() => sum()).toThrow(
+      new Error("sum requires an array of numbers")
+    );
+})
+})
+
+
+
+
+
+
+
+
+
+

From 02e7fdcac7373d9e50539793e4a3e8b29dbd698d Mon Sep 17 00:00:00 2001
From: Rahana Suleiman <rahanasuleiman8@gmail.com>
Date: Mon, 2 Nov 2026 22:10:16 +0000
Subject: [PATCH 24/24] Refactor includes function to use for...of loop for
 improved readability

---
 Sprint-1/refactor/includes.js | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 29dad81f0..8474eb211 100644
--- a/Sprint-1/refactor/includes.js
+++ b/Sprint-1/refactor/includes.js
@@ -1,8 +1,7 @@
-// Refactor the implementation of includes to use a for...of loop
+// Refactored implementation of includes using a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  for (const element of list) {
     if (element === target) {
       return true;
     }
@@ -10,4 +9,4 @@ function includes(list, target) {
   return false;
 }
 
-module.exports = includes;
+module.exports = includes;
\ No newline at end of file