import { describe, expect, it } from "vitest";
import { moveTarget } from "./moveInList";

describe("moveTarget", () => {
  it("sends an item to the top, one up, one down, or to the bottom", () => {
    expect(moveTarget(2, 5, "top")).toBe(0);
    expect(moveTarget(2, 5, "up")).toBe(1);
    expect(moveTarget(2, 5, "down")).toBe(3);
    expect(moveTarget(2, 5, "bottom")).toBe(4);
  });

  it("is null for a move that goes nowhere: the first up, the last down", () => {
    expect(moveTarget(0, 5, "top")).toBeNull();
    expect(moveTarget(0, 5, "up")).toBeNull();
    expect(moveTarget(4, 5, "down")).toBeNull();
    expect(moveTarget(4, 5, "bottom")).toBeNull();
    expect(moveTarget(0, 1, "down")).toBeNull();
  });

  it("is null for an index outside the list", () => {
    expect(moveTarget(-1, 5, "top")).toBeNull();
    expect(moveTarget(5, 5, "up")).toBeNull();
  });
});