Module-Data-Groups/Sprint-1/fix/median.test.js at 3db21bf8b49f87ae6b7d6b592742e2aa9d90fbe8 · CodeYourFuture/Module-Data-Groups · GitHub

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// median.test.js

// Someone has implemented calculateMedian but it isn't
// passing all the tests...
// Fix the implementation of calculateMedian so it passes all tests

const calculateMedian = require("./median.js");

describe("calculateMedian", () => {
  [
    { input: [1.5, 2.5, 3.5], expected: 2.5 },
    { input: [-2, -4, -6, -10], expected: -5 },
    { input: [3, 3, 3, 3, 3], expected: 3 },
    { input: [1, 3], expected: 2 },
    { input: [1], expected: 1 },
    { input: [1, 2, 3], expected: 2 },
    { input: [1, 2, 3, 4, 5], expected: 3 },
    { input: [1, 2, 3, 4], expected: 2.5 },
    { input: [1, 2, 3, 4, 5, 6], expected: 3.5 },
  ].forEach(({ input, expected }) =>
    it(`returns the median for [${input}]`, () =>
      expect(calculateMedian(input)).toEqual(expected))
  );

  [
    { input: [-5, -1, -3], expected: -3 },
    { input: [2, 2, 2, 2], expected: 2 },
    { input: [8, 4], expected: 6 },
    { input: [3, 1, 2], expected: 2 },
    { input: [5, 1, 3, 4, 2], expected: 3 },
    { input: [4, 2, 1, 3], expected: 2.5 },
    { input: [6, 1, 5, 3, 2, 4], expected: 3.5 },
    { input: [110, 20, 0], expected: 20 },
    { input: [6, -2, 2, 12, 14], expected: 6 },
  ].forEach(({ input, expected }) =>
    it(`returns the correct median for unsorted array [${input}]`, () =>
      expect(calculateMedian(input)).toEqual(expected))
  );

  it("doesn't modify the input array [3, 1, 2]", () => {
    const list = [3, 1, 2];
    calculateMedian(list);
    expect(list).toEqual([3, 1, 2]);
  });

  [
    "not an array",
    123,
    null,
    undefined,
    {},
    [],
    ["apple", null, undefined],
  ].forEach((val) =>
    it(`returns null for non-numeric array (${val})`, () =>
      expect(calculateMedian(val)).toBe(null))
  );

  [
    { input: ["a", null, 5, undefined], expected: 5 },
    { input: [1, 2, "3", null, undefined, 4], expected: 2 },
    { input: ["apple", 1, 2, 3, "banana", 4], expected: 2.5 },
    { input: [1, "2", 3, "4", 5], expected: 3 },
    { input: [1, "apple", 2, null, 3, undefined, 4], expected: 2.5 },
    { input: [3, "apple", 1, null, 2, undefined, 4], expected: 2.5 },
    { input: ["banana", 5, 3, "apple", 1, 4, 2], expected: 3 },
  ].forEach(({ input, expected }) =>
    it(`filters out non-numeric values and calculates the median for [${input}]`, () =>
      expect(calculateMedian(input)).toEqual(expected))
  );
});