feat: show my bookings on a month calendar

tests/Model/MonthGridTest.php

@@ -0,0 +1,129 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Model;
+
+use App\Model\MonthGrid;
+use PHPUnit\Framework\TestCase;
+
+class MonthGridTest extends TestCase
+{
+    public function testTheGridIsAlwaysSixWeeksOfSevenDays(): void
+    {
+        // February 2026 needs four rows; the grid still renders six, so paging never changes its
+        // height.
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-02-15'), new \DateTimeImmutable('2026-02-15'));
+
+        self::assertCount(6, $grid->weeks);
+
+        foreach ($grid->weeks as $week) {
+            self::assertCount(7, $week);
+        }
+    }
+
+    public function testItStartsOnTheMondayOnOrBeforeTheFirst(): void
+    {
+        // 1 September 2026 is a Tuesday, so the grid opens on 31 August.
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-09-21'), new \DateTimeImmutable('2026-09-21'));
+
+        self::assertSame('2026-08-31', $grid->gridStart->format('Y-m-d'));
+        self::assertSame('2026-09-01', $grid->monthStart->format('Y-m-d'));
+        self::assertSame('1', $grid->gridStart->format('N'));
+    }
+
+    public function testAMonthBeginningOnAMondayStartsOnThatMonday(): void
+    {
+        // 1 June 2026 is a Monday: no leading days at all.
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-06-10'), new \DateTimeImmutable('2026-06-10'));
+
+        self::assertSame('2026-06-01', $grid->gridStart->format('Y-m-d'));
+    }
+
+    public function testTheEndIsTheLastCellOfTheGrid(): void
+    {
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-09-21'), new \DateTimeImmutable('2026-09-21'));
+
+        self::assertSame('2026-10-11', $grid->gridEnd->format('Y-m-d'));
+        self::assertEquals($grid->weeks[5][6]->date, $grid->gridEnd);
+    }
+
+    public function testEveryCellIsTheDayAfterTheOneBefore(): void
+    {
+        // Guards the modify('+1 day') walk: March and October carry the DST switches, where naive
+        // arithmetic on timestamps would repeat or skip a day.
+        foreach (['2026-03-15', '2026-10-15'] as $inMonth) {
+            $grid = MonthGrid::around(new \DateTimeImmutable($inMonth), new \DateTimeImmutable($inMonth));
+
+            $expected = $grid->gridStart;
+            foreach ($grid->weeks as $week) {
+                foreach ($week as $day) {
+                    self::assertSame($expected->format('Y-m-d'), $day->date->format('Y-m-d'));
+                    self::assertSame('00:00:00', $day->date->format('H:i:s'));
+                    $expected = $expected->modify('+1 day');
+                }
+            }
+        }
+    }
+
+    public function testDaysOutsideTheMonthAreFlagged(): void
+    {
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-09-21'), new \DateTimeImmutable('2026-09-21'));
+
+        self::assertFalse($grid->weeks[0][0]->inMonth, '31 August is a leading day.');
+        self::assertTrue($grid->weeks[0][1]->inMonth, '1 September is in the month.');
+        self::assertFalse($grid->weeks[5][6]->inMonth, '11 October is a trailing day.');
+    }
+
+    public function testTodayIsNeitherPastNorAnyOtherDay(): void
+    {
+        $today = new \DateTimeImmutable('2026-09-21');
+        $grid = MonthGrid::around($today, $today);
+
+        $flagged = [];
+        foreach ($grid->weeks as $week) {
+            foreach ($week as $day) {
+                if ($day->isToday) {
+                    $flagged[] = $day->date->format('Y-m-d');
+                    self::assertFalse($day->isPast, 'Today is not past.');
+                }
+            }
+        }
+
+        self::assertSame(['2026-09-21'], $flagged);
+    }
+
+    public function testPastAndWeekendFlags(): void
+    {
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-09-21'), new \DateTimeImmutable('2026-09-21'));
+
+        $days = [];
+        foreach ($grid->weeks as $week) {
+            foreach ($week as $day) {
+                $days[$day->key()] = $day;
+            }
+        }
+
+        self::assertTrue($days['2026-09-20']->isPast);
+        self::assertFalse($days['2026-09-22']->isPast);
+        // 19/20 September 2026 is a Saturday/Sunday.
+        self::assertTrue($days['2026-09-19']->isWeekend);
+        self::assertTrue($days['2026-09-20']->isWeekend);
+        self::assertFalse($days['2026-09-21']->isWeekend);
+    }
+
+    public function testTheTimePartOfTheGivenDayIsIgnored(): void
+    {
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-09-21 17:43:12'), new \DateTimeImmutable('2026-09-21'));
+
+        self::assertSame('2026-09-01 00:00:00', $grid->monthStart->format('Y-m-d H:i:s'));
+        self::assertTrue($grid->weeks[3][0]->isToday, 'Today must still be recognised.');
+    }
+
+    public function testTheKeyIsTheDayItIndexesPayloadBy(): void
+    {
+        $grid = MonthGrid::around(new \DateTimeImmutable('2026-09-21'), new \DateTimeImmutable('2026-09-21'));
+
+        self::assertSame('2026-08-31', $grid->weeks[0][0]->key());
+    }
+}