feat: all-season assignments

tests/Config/SeasonCalendarTest.php

@@ -71,6 +71,52 @@ class SeasonCalendarTest extends TestCase
         (new SeasonCalendar('xx-yy', '04-01'))->seasonYearFor(new \DateTimeImmutable('2025-01-01'));
     }
 
+    /**
+     * @dataProvider currentOrUpcomingDates
+     */
+    public function testCurrentOrUpcomingSeasonYear(string $date, int $expected): void
+    {
+        $this->assertSame(
+            $expected,
+            $this->winter()->currentOrUpcomingSeasonYear(new \DateTimeImmutable($date))
+        );
+    }
+
+    public static function currentOrUpcomingDates(): iterable
+    {
+        yield 'inside the season' => ['2024-12-20', 2024];
+        yield 'last day of the season' => ['2025-04-01', 2024];
+        yield 'day after the season ends falls forward' => ['2025-04-02', 2025];
+        yield 'high summer falls forward' => ['2025-07-15', 2025];
+        yield 'day before the next season starts' => ['2025-10-31', 2025];
+        yield 'first day of the next season' => ['2025-11-01', 2025];
+        yield 'off-season in january is impossible for this window' => ['2025-01-05', 2024];
+    }
+
+    public function testCurrentOrUpcomingSeasonYearFallsForwardAcrossTheTurnOfTheYear(): void
+    {
+        // A window that ends before it starts in the same calendar year is the wrapping case;
+        // one that does not wrap has its off-season on both sides of the window instead.
+        $summer = new SeasonCalendar('05-01', '09-30');
+
+        $this->assertSame(2025, $summer->currentOrUpcomingSeasonYear(new \DateTimeImmutable('2025-03-01')));
+        $this->assertSame(2025, $summer->currentOrUpcomingSeasonYear(new \DateTimeImmutable('2025-06-01')));
+        $this->assertSame(2026, $summer->currentOrUpcomingSeasonYear(new \DateTimeImmutable('2025-11-20')));
+    }
+
+    public function testWindowFor(): void
+    {
+        [$start, $end] = $this->winter()->windowFor(2024);
+
+        $this->assertSame('2024-11-01', $start->format('Y-m-d'));
+        $this->assertSame('2025-04-01', $end->format('Y-m-d'));
+
+        [$start, $end] = (new SeasonCalendar('05-01', '09-30'))->windowFor(2025);
+
+        $this->assertSame('2025-05-01', $start->format('Y-m-d'));
+        $this->assertSame('2025-09-30', $end->format('Y-m-d'));
+    }
+
     /**
      * @dataProvider provideUpcomingSeasonDates
      */