Created unit tests for function used for calculating avg value from a…

…n array.

cli-tests/helpers/reducers/avg-by-prop.spec.mjs

@@ -0,0 +1,69 @@
+import { getAverageByProp } from "#helpers/reducers/avg-by-prop.mjs";
+const FUNCTIONS = [
+  {
+    runtime: "nodejs18.x",
+    memorySize: 1024,
+    ephemeralStorage: {
+      size: 512,
+    },
+  },
+  {
+    runtime: "nodejs18.x",
+    memorySize: 1024,
+    ephemeralStorage: {
+      size: 512,
+    },
+  },
+  {
+    runtime: "nodejs20.x",
+    memorySize: 128,
+    ephemeralStorage: {
+      size: 512,
+    },
+  },
+  {
+    runtime: "nodejs20.x",
+    memorySize: 128,
+    ephemeralStorage: {
+      size: 512,
+    },
+  },
+];
+
+describe("getAverageByProp", () => {
+  test.each([
+    ["memorySize", 576],
+    ["ephemeralStorage.size", 512],
+  ])(
+    "Should return the average value for the specified dotNotation.",
+    (dotNotation, expected) => {
+      const result = getAverageByProp(FUNCTIONS, dotNotation);
+
+      expect(result).toEqual(expected);
+    }
+  );
+
+  test.each([[null], [undefined], [""], [false], [true], [1], [522], [54]])(
+    "Should throw an error for bad dot notation entries %#",
+    (dotNotation) => {
+      expect(() => {
+        getAverageByProp(FUNCTIONS, dotNotation);
+      }).toThrow("JSON dot notation is required.");
+    }
+  );
+
+  test.each([[null], [undefined], [""], [false], [true], [1], [522], [54]])(
+    "Should throw an invalid array error %#",
+    (nonArrayInput) => {
+      expect(() => {
+        getAverageByProp(nonArrayInput, "memorySize");
+      }).toThrow("Invalid array");
+    }
+  );
+
+  it("Should return 0 for empty arrays", () => {
+    const result = getAverageByProp([], "ephemeralStorage.size");
+
+    expect(result).toEqual(0);
+  });
+});

cli/helpers/reducers/avg-by-prop.mjs

@@ -4,24 +4,28 @@ import { getNestedProperty } from "../json/get-nested-property.mjs";
  * @function getAverageByProp
  * @description Method used for retrieving the average value for the specified property
  * @param {object[]} array List of input objects
- * @param {string} property JSON notation path of property that will be used for average calculation.
+ * @param {string} dotNotation JSON notation path of property that will be used for average calculation.
  * @returns {number}
  */
-export function getAverageByProp(array, property) {
+export function getAverageByProp(array, dotNotation) {
   if (!Array.isArray(array)) {
     throw new Error("Invalid array");
   }
 
-  if (typeof property !== "string") {
-    throw new Error("Property input should be a string.");
+  if (typeof dotNotation !== "string") {
+    throw new Error("JSON dot notation is required.");
+  }
+
+  if (!dotNotation) {
+    throw new Error("JSON dot notation is required.");
   }
 
   if (array && array.length <= 0) {
     return 0;
   }
 
   const total = (array || []).reduce(
-    (total, item) => total + (getNestedProperty(item, property) || 0),
+    (total, item) => total + (getNestedProperty(item, dotNotation) || 0),
     0
   );