pike/val Public Public: anyone can read this; nobody can change it.

import { expect, test } from "bun:test";

import { makeGrid } from "./grid.ts";

const LINES = ["#########", "#.......#", "#.##.##.#", "#.......#", "#########"];

const cells = (g: ReturnType<typeof makeGrid>) => g.cellsOf(".");

test("many distances to one fixed target build one field", () => {

  const g = makeGrid(LINES, 10);

  const target = cells(g)[0]!;

  for (const from of cells(g)) g.walkDistance(from, target);

  expect(g.fieldsBuilt()).toBe(1);

});

test("varying the target builds a field per target", () => {

  const g = makeGrid(LINES, 10);

  const from = cells(g)[0]!;

  for (const to of cells(g)) g.walkDistance(from, to);

  expect(g.fieldsBuilt()).toBe(cells(g).length);

});

test("pathStep shares the field walkDistance built for the goal", () => {

  const g = makeGrid(LINES, 10);

  const goal = cells(g).at(-1)!;

  for (const from of cells(g)) {

    g.walkDistance(from, goal);

    g.pathStep(from, goal);

  }

  expect(g.fieldsBuilt()).toBe(1);

});

test("walk distance is symmetric, so swapping the arguments is safe", () => {

  const g = makeGrid(LINES, 10);

  for (const a of cells(g)) for (const b of cells(g)) expect(g.walkDistance(a, b)).toBe(g.walkDistance(b, a));

});

test("clearPaths forgets the fields, so the next ask builds again", () => {

  const g = makeGrid(LINES, 10);

  const [a, b] = cells(g);

  g.walkDistance(a!, b!);

  g.clearPaths();

  g.walkDistance(a!, b!);

  expect(g.fieldsBuilt()).toBe(2);

});