Add unit tests for quality of Aged Brie

src/test/kotlin/com/gildedrose/QualityTest.kt

@@ -85,4 +85,30 @@ class QualityTest {
         val expectedQuality = (initialItemQuality - days * 2).coerceAtLeast(0)
         assertThat(item.quality).isEqualTo(expectedQuality)
     }
+
+    @Test
+    fun givenAgedBrie_afterAnyNumberOfDays_shouldIncreaseQualityByNumberOfDays() {
+        val days = generateRandomNumber()
+        val item = Item("Aged Brie", generateRandomNumber(), (0..50).shuffled().last())
+        val initialItemQuality = item.quality
+        val app = GildedRose(arrayOf(item))
+
+        app.advanceTimeBy(days)
+
+        val expectedQuality = (initialItemQuality + days).coerceAtMost(50)
+        assertThat(item.quality).isEqualTo(expectedQuality)
+    }
+
+    @Test
+    fun givenBackstagePass_afterAnyNumberOfDays_shouldIncreaseQualityByNumberOfDays() {
+        val days = generateRandomNumber()
+        val item = Item("Backstage passes to a TAFKAL80ETC concert", generateRandomNumber(), (0..50).shuffled().last())
+        val initialItemQuality = item.quality
+        val app = GildedRose(arrayOf(item))
+
+        app.advanceTimeBy(days)
+
+        val expectedQuality = (initialItemQuality + days).coerceAtMost(50)
+        assertThat(item.quality).isEqualTo(expectedQuality)
+    }
 }

texttest/specs.txt

@@ -1,13 +1,13 @@
 SPECS
     LOGIC
         # - sellIn decreases every day
-        - Item.quality
+        # - Item.quality
             # - is >= 0 && <= 50
             # - decrements with number of days until sellIn is 0 then with the double of it
-        - Sulfuras
+        # - Sulfuras
             # sellIn = 0 // doesnt change
             # quality is 80 and does not decrease
-        - AgedBrie increases in quality
+        # - AgedBrie increases in quality
         - BackstagePasses
             increases in quality like AgedBrie
                 sellIn <= 0 - quality = 0