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import { describe, expect, it } from "vitest";
import { BalanceToBudgetRatio } from "./balanceToBudgetRatio";
import { Gbp } from "./currency/gbp";
describe("balanceToBudgetRatio", () => {
it("new() returns null when budget is null", () => {
const result = BalanceToBudgetRatio.new(new Gbp(1, 0, 1), null);
expect(result).toBeNull();
});
it("toString() rounds to 2 decimal places", () => {
const mockCurrencyPi = { valueOf: () => Math.PI };
const mockCurrencyUnit = { valueOf: () => 1 };
const sut = BalanceToBudgetRatio.new(mockCurrencyPi, {
quantity: mockCurrencyUnit,
period: 42,
});
const result = sut?.toString();
expect(result).toBe("3.14");
});
it("new() sets normalisedRatio to 1 when balance and budget are equal and positive", () => {
const twoFifty = new Gbp(2, 50, 1);
const result = BalanceToBudgetRatio.new(twoFifty, {
quantity: twoFifty,
period: 42,
});
expect(result?.normalisedRatio).toBeCloseTo(1.0);
});
it("new() sets normalisedRatio to 2 when balance is twice budget", () => {
const twoFifty = new Gbp(2, 50, 1);
const oneTwentyFive = new Gbp(1, 25, 1);
const result = BalanceToBudgetRatio.new(twoFifty, {
quantity: oneTwentyFive,
period: 42,
});
expect(result?.normalisedRatio).toBeCloseTo(2.0);
});
it("new() sets normalisedRatio to -2 when a negative balance is -1 * twice budget", () => {
const minusTwoFifty = new Gbp(2, 50, -1);
const oneTwentyFive = new Gbp(1, 25, 1);
const result = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: oneTwentyFive,
period: 42,
});
expect(result?.normalisedRatio).toBeCloseTo(-2.0);
});
it("new() sets normalisedRatio to -0.5 when balance is -1 * half a negative budget", () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const minusTwoFifty = new Gbp(2, 50, -1);
const result = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: minusTwoFifty,
period: 42,
});
expect(result?.normalisedRatio).toBeCloseTo(-0.5);
});
it("new() sets normalisedRatio to 1 when balance and budget are equal and negative", () => {
const minusTwoFifty = new Gbp(2, 50, -1);
const result = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: minusTwoFifty,
period: 42,
});
expect(result?.normalisedRatio).toBeCloseTo(1.0);
});
it('new() sets recommended action to "arrears" when ratio is less than 0', () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const minusTwoFifty = new Gbp(2, 50, -1);
const result = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: minusTwoFifty,
period: 42,
});
expect(result?.recommendedAction).toBe("arrears");
});
it('new() sets recommended action to "save" when ratio is between 0 and 1', () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const twoFifty = new Gbp(2, 50, 1);
const result = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: twoFifty,
period: 42,
});
expect(result?.recommendedAction).toBe("save");
});
it('new() sets recommended action to "spend" when ratio is larger than 1', () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const twoFifty = new Gbp(2, 50, 1);
const result = BalanceToBudgetRatio.new(twoFifty, {
quantity: oneTwentyFive,
period: 42,
});
expect(result?.recommendedAction).toBe("spend");
});
it("normalises to a factor of 2 when all ratios are positive", () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const twoFifty = new Gbp(2, 50, 1);
const twoOverOne = BalanceToBudgetRatio.new(twoFifty, {
quantity: oneTwentyFive,
period: 42,
});
const twoOverTwo = BalanceToBudgetRatio.new(twoFifty, {
quantity: twoFifty,
period: 42,
});
const oneOverOne = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: oneTwentyFive,
period: 42,
});
const oneOverTwo = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: twoFifty,
period: 42,
});
const normaliser = BalanceToBudgetRatio.makeNormaliser(
twoOverOne,
twoOverTwo,
oneOverOne,
oneOverTwo,
);
expect(normaliser(twoOverOne).normalisedRatio).toBeCloseTo(1.0);
expect(normaliser(twoOverTwo).normalisedRatio).toBeCloseTo(0.5);
expect(normaliser(oneOverOne).normalisedRatio).toBeCloseTo(0.5);
expect(normaliser(oneOverTwo).normalisedRatio).toBeCloseTo(0.25);
});
it("normalises to a factor of 2 when all ratios are negative", () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const twoFifty = new Gbp(2, 50, 1);
const minusOneTwentyFive = new Gbp(1, 25, -1);
const minusTwoFifty = new Gbp(2, 50, -1);
const minusTwoOverOne = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: oneTwentyFive,
period: 42,
});
const minusTwoOverTwo = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: twoFifty,
period: 42,
});
const minusOneOverOne = BalanceToBudgetRatio.new(minusOneTwentyFive, {
quantity: oneTwentyFive,
period: 42,
});
const minusOneOverTwo = BalanceToBudgetRatio.new(minusOneTwentyFive, {
quantity: twoFifty,
period: 42,
});
const normaliser = BalanceToBudgetRatio.makeNormaliser(
minusTwoOverOne,
minusTwoOverTwo,
minusOneOverOne,
minusOneOverTwo,
);
expect(normaliser(minusTwoOverOne).normalisedRatio).toBeCloseTo(-1.0);
expect(normaliser(minusTwoOverTwo).normalisedRatio).toBeCloseTo(-0.5);
expect(normaliser(minusOneOverOne).normalisedRatio).toBeCloseTo(-0.5);
expect(normaliser(minusOneOverTwo).normalisedRatio).toBeCloseTo(-0.25);
});
it("normalises to a factor of 2 when ratios are a mix of positive and negative", () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const twoFifty = new Gbp(2, 50, 1);
const minusOneTwentyFive = new Gbp(1, 25, -1);
const minusTwoFifty = new Gbp(2, 50, -1);
const twoOverOne = BalanceToBudgetRatio.new(twoFifty, {
quantity: oneTwentyFive,
period: 42,
});
const twoOverTwo = BalanceToBudgetRatio.new(twoFifty, {
quantity: twoFifty,
period: 42,
});
const oneOverOne = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: oneTwentyFive,
period: 42,
});
const oneOverTwo = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: twoFifty,
period: 42,
});
const minusTwoOverOne = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: oneTwentyFive,
period: 42,
});
const minusTwoOverTwo = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: twoFifty,
period: 42,
});
const minusOneOverOne = BalanceToBudgetRatio.new(minusOneTwentyFive, {
quantity: oneTwentyFive,
period: 42,
});
const minusOneOverTwo = BalanceToBudgetRatio.new(minusOneTwentyFive, {
quantity: twoFifty,
period: 42,
});
const normaliser = BalanceToBudgetRatio.makeNormaliser(
twoOverOne,
twoOverTwo,
oneOverOne,
oneOverTwo,
minusTwoOverOne,
minusTwoOverTwo,
minusOneOverOne,
minusOneOverTwo,
);
expect(normaliser(twoOverOne).normalisedRatio).toBeCloseTo(1.0);
expect(normaliser(twoOverTwo).normalisedRatio).toBeCloseTo(0.5);
expect(normaliser(oneOverOne).normalisedRatio).toBeCloseTo(0.5);
expect(normaliser(oneOverTwo).normalisedRatio).toBeCloseTo(0.25);
expect(normaliser(minusTwoOverOne).normalisedRatio).toBeCloseTo(-1.0);
expect(normaliser(minusTwoOverTwo).normalisedRatio).toBeCloseTo(-0.5);
expect(normaliser(minusOneOverOne).normalisedRatio).toBeCloseTo(-0.5);
expect(normaliser(minusOneOverTwo).normalisedRatio).toBeCloseTo(-0.25);
});
it("sorts large positive ratios before small positive ratios", () => {
const oneTwentyFive = new Gbp(1, 25, 1);
const twoFifty = new Gbp(2, 50, 1);
const twoOverTwo = BalanceToBudgetRatio.new(twoFifty, {
quantity: twoFifty,
period: 42,
});
const oneOverTwo = BalanceToBudgetRatio.new(oneTwentyFive, {
quantity: twoFifty,
period: 42,
});
const resultLeftways = BalanceToBudgetRatio.compare(twoOverTwo, oneOverTwo);
const resultRightways = BalanceToBudgetRatio.compare(
oneOverTwo,
twoOverTwo,
);
expect(resultLeftways).toBeCloseTo(-resultRightways);
expect(resultLeftways).toBeLessThan(0);
});
it("sorts small negative ratios before large negative ratios", () => {
const twoFifty = new Gbp(2, 50, 1);
const minusOneTwentyFive = new Gbp(1, 25, -1);
const minusTwoFifty = new Gbp(2, 50, -1);
const minusTwoOverTwo = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: twoFifty,
period: 42,
});
const minusOneOverTwo = BalanceToBudgetRatio.new(minusOneTwentyFive, {
quantity: twoFifty,
period: 42,
});
const resultLeftways = BalanceToBudgetRatio.compare(
minusOneOverTwo,
minusTwoOverTwo,
);
const resultRightways = BalanceToBudgetRatio.compare(
minusTwoOverTwo,
minusOneOverTwo,
);
expect(resultLeftways).toBeCloseTo(-resultRightways);
expect(resultLeftways).toBeLessThan(0);
});
it("sorts positive ratios before negative ratios", () => {
const twoFifty = new Gbp(2, 50, 1);
const minusTwoFifty = new Gbp(2, 50, -1);
const twoOverTwo = BalanceToBudgetRatio.new(twoFifty, {
quantity: twoFifty,
period: 42,
});
const minusTwoOverTwo = BalanceToBudgetRatio.new(minusTwoFifty, {
quantity: twoFifty,
period: 42,
});
const resultLeftways = BalanceToBudgetRatio.compare(
twoOverTwo,
minusTwoOverTwo,
);
const resultRightways = BalanceToBudgetRatio.compare(
minusTwoOverTwo,
twoOverTwo,
);
expect(resultLeftways).toBeCloseTo(-resultRightways);
expect(resultLeftways).toBeLessThan(0);
});
});
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