diff --git a/Java/src/test/java/com/gildedrose/GildedRoseTest.java b/Java/src/test/java/com/gildedrose/GildedRoseTest.java
index 8ae29eec..ff6fcfe1 100644
--- a/Java/src/test/java/com/gildedrose/GildedRoseTest.java
+++ b/Java/src/test/java/com/gildedrose/GildedRoseTest.java
@@ -1,17 +1,166 @@
 package com.gildedrose;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 class GildedRoseTest {
 
-    @Test
-    void foo() {
-        Item[] items = new Item[] { new Item("foo", 0, 0) };
-        GildedRose app = new GildedRose(items);
-        app.updateQuality();
-        assertEquals("fixme", app.items[0].name);
-    }
+  private GildedRose gildedRose;
 
+  @BeforeEach
+  void setup() {
+    gildedRose = new GildedRose(new Item[0]);
+  }
+
+  @Test
+  void qualityDegradesWhenDateHasPassed() {
+    Item item = new ItemBuilder().name("standard item").sellIn(2).quality(30).build();
+
+    gildedRose.updateQuality(item);
+    assertEquals(1, item.sellIn);
+    assertEquals(29, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(0, item.sellIn);
+    assertEquals(28, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(-1, item.sellIn);
+    assertEquals(26, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(-2, item.sellIn);
+    assertEquals(24, item.quality);
+  }
+
+  @Test
+  void conjuredItemsDegradesTwiceAsFast() {
+    Item item = ItemFixture.conjured().sellIn(2).quality(30).build();
+
+    gildedRose.updateQuality(item);
+    assertEquals(1, item.sellIn);
+    assertEquals(28, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(0, item.sellIn);
+    assertEquals(26, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(-1, item.sellIn);
+    assertEquals(24, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(-2, item.sellIn);
+    assertEquals(22, item.quality);
+  }
+
+  @Test
+  void qualityNeverNegative() {
+    Item item = ItemFixture.standard().sellIn(1).quality(1).build();
+
+    gildedRose.updateQuality(item);
+    assertEquals(0, item.sellIn);
+    assertEquals(0, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(-1, item.sellIn);
+    assertEquals(0, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(-2, item.sellIn);
+    assertEquals(0, item.quality);
+  }
+
+  @Test
+  void agedBrieIncreasesQuality() {
+    Item item = ItemFixture.agedBrie().sellIn(5).quality(10).build();
+
+    gildedRose.updateQuality(item);
+    assertEquals(4, item.sellIn);
+    assertEquals(11, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(3, item.sellIn);
+    assertEquals(12, item.quality);
+  }
+
+  @Test
+  void qualityNeverBiggerThan50() {
+    Item item = ItemFixture.agedBrie().sellIn(5).quality(49).build();
+    gildedRose.updateQuality(item);
+    assertEquals(50, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(50, item.quality);
+  }
+
+  @Test
+  void qualityNeverBiggerThan50AtConstruction() {
+    assertThrows(
+        IllegalArgumentException.class, () -> ItemFixture.agedBrie().sellIn(5).quality(51).build());
+  }
+
+  @Test
+  void qualityNeverBiggerThan50AtConstructionUnlessSulfuras() {
+    ItemFixture.sulfuras().sellIn(5).build();
+  }
+
+  @Test
+  void sulfurasIsNotSellable() {
+    Item item = ItemFixture.sulfuras().sellIn(5).build();
+    gildedRose.updateQuality(item);
+    assertEquals(80, item.quality);
+    assertEquals(5, item.sellIn);
+  }
+
+  @Test
+  void backStagePasses() {
+    Item item = ItemFixture.backstagePass().sellIn(12).quality(20).build();
+
+    gildedRose.updateQuality(item);
+    assertEquals(21, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(22, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(24, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(26, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(28, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(30, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(32, item.quality);
+
+    item.quality = 20;
+    gildedRose.updateQuality(item);
+    assertEquals(23, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(26, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(29, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(32, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(35, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(0, item.quality);
+
+    gildedRose.updateQuality(item);
+    assertEquals(0, item.quality);
+  }
 }