calculateMean.test.ts

import { calculateMean } from "../calculateMean";

describe("Tests for AverageMean", () => {
  it("should be a function", () => {
    expect(typeof calculateMean).toEqual("function");
  });

  it("should throw error for invalid input", () => {
    expect(() => calculateMean([])).toThrow();
  });

  it("should return the mean of an array of consecutive numbers", () => {
    const meanFunction = calculateMean([1, 2, 3, 4]);
    expect(meanFunction).toBe(2.5);
  });

  it("should return the mean of an array of numbers", () => {
    const meanFunction = calculateMean([10, 40, 100, 20]);
    expect(meanFunction).toBe(42.5);
  });

  it("should return the mean of an array of decimal numbers", () => {
    const meanFunction = calculateMean([1.3, 12.67, 99.14, 20]);
    expect(meanFunction).toBe(33.2775);
  });

  it("should return the mean of an array of numbers, including negatives", () => {
    const meanFunction = calculateMean([10, -40, 100, -20]);
    expect(meanFunction).toBe(12.5);
  });
});