Improve JS1 week2 exercise 2 (#15)

* Show expected/actual - this both helps the students debug, and better
  matches what they should see professionally from tests.
* Make question about removing element less misleading (its old wording
  suggests modifying the array, before telling you not to).
* Add decimal edge case.

Author: illicitonion

week-2/2-mandatory/2-function-creation.js

@@ -18,11 +18,8 @@ Tip: use logical operators
 function validate(num) {}
 
 /* 
-Write a function that removes an element from an array
-The function must:
-- NOT change the original array
-- return a new array with the item removed
-- remove the item at the specified index
+Write a function that returns a copy of the given array arr, but with the element at the given index, index removed.
+The function must NOT change the original array, arr.
 */
 
 function remove(arr, index) {
@@ -43,6 +40,27 @@ function formatPercentage(arr) {
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
+const util = require('util');
+
+function test(test_name, actual, expected) {
+  let status;
+
+  let isEqual;
+  if (Array.isArray(expected)) {
+    isEqual = arraysEqual(actual, expected);
+  } else {
+    isEqual = actual === expected;
+  }
+
+  if (isEqual) {
+    status = "PASSED";
+  } else {
+    status = `FAILED: expected: ${util.inspect(expected)} but your function returned: ${util.inspect(actual)}`;
+  }
+
+  console.log(`${test_name}: ${status}`);
+}
+
 function arraysEqual(a, b) {
   if (a === b) return true;
   if (a == null || b == null) return false;
@@ -55,62 +73,49 @@ function arraysEqual(a, b) {
   return true;
 }
 
-function test(test_name, expr) {
-  let status;
-  if (expr) {
-    status = "PASSED";
-  } else {
-    status = "FAILED";
-  }
-
-  console.log(`${test_name}: ${status}`);
-}
-
 test(
   "tidyUpString function works - case 1",
-  arraysEqual(tidyUpString(["/Daniel ", "irina ", " Gordon", "ashleigh "]), [
+  tidyUpString(["/Daniel ", "irina ", " Gordon", "ashleigh "]), [
     "daniel",
     "irina",
     "gordon",
     "ashleigh"
-  ])
+  ]
 );
 test(
   "tidyUpString function works - case 2",
-  arraysEqual(
-    tidyUpString([" /Sanyia ", " Michael ", "AnTHonY ", "   Tim   "]),
-    ["sanyia", "michael", "anthony", "tim"]
-  )
+  tidyUpString([" /Sanyia ", " Michael ", "AnTHonY ", "   Tim   "]),
+  ["sanyia", "michael", "anthony", "tim"]
 );
 
-test("validate function works - case 1", validate(10) === true);
-test("validate function works - case 2", validate(18) === true);
-test("validate function works - case 3", validate(17) === false);
-test("validate function works - case 4", validate("Ten") === false);
-test("validate function works - case 5", validate(108) === false);
+test("validate function works - case 1", validate(10), true);
+test("validate function works - case 2", validate(18), true);
+test("validate function works - case 3", validate(17), false);
+test("validate function works - case 4", validate("Ten"), false);
+test("validate function works - case 5", validate(108), false);
 
 test(
   "remove function works - case 1",
-  arraysEqual(remove([10, 293, 292, 176, 29], 3), [10, 293, 292, 29])
+  remove([10, 293, 292, 176, 29], 3), [10, 293, 292, 29]
 );
 test(
-  "remove function works - case 1",
-  arraysEqual(remove(["a", "b", "c", "d", "e", "f", "g"], 6), [
+  "remove function works - case 2",
+  remove(["a", "b", "c", "d", "e", "f", "g"], 6), [
     "a",
     "b",
     "c",
     "d",
     "e",
     "f"
-  ])
+  ]
 );
 
 test(
   "formatPercentage function works - case 1",
-  arraysEqual(formatPercentage([23, 18, 187.2, 0.372]), [
+  formatPercentage([23, 18.103, 187.2, 0.372]), [
     "23%",
-    "18%",
+    "18.1%",
     "100%",
     "0.37%"
-  ])
-);
+  ]
+);