Add unit tests for CompatibleMaterial

This especially eases adding support for new Minecraft versions

Core/src/test/java/com/songoda/core/compatibility/material/CompatibleMaterialTest.java

@@ -0,0 +1,85 @@
+package com.songoda.core.compatibility.material;
+
+import be.seeseemelk.mockbukkit.MockBukkit;
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+class CompatibleMaterialTest {
+    @BeforeEach
+    void setUp() {
+        MockBukkit.mock();
+    }
+
+    @AfterEach
+    void tearDown() {
+        MockBukkit.unmock();
+    }
+
+    @Test
+    void getMaterialForNull() {
+        assertNull(CompatibleMaterial.getMaterial((Material) null));
+        assertNull(CompatibleMaterial.getMaterial((ItemStack) null));
+    }
+
+    @Test
+    void getMaterialForAllBukkitMaterials() {
+        Map<CompatibleMaterial, Material> returnedMaterials = new HashMap<>(Material.values().length);
+        for (Material bukkitMaterial : Material.values()) {
+            CompatibleMaterial compatibleMaterial = CompatibleMaterial.getMaterial(bukkitMaterial);
+
+            if (bukkitMaterial.name().startsWith("LEGACY_")) {
+                assertNull(compatibleMaterial);
+                continue;
+            }
+            assertNotNull(compatibleMaterial, () -> "Could not get an CompatibleMaterial for Material." + bukkitMaterial.name());
+            assertEquals(bukkitMaterial, compatibleMaterial.getMaterial());
+            assertEquals(compatibleMaterial, CompatibleMaterial.getMaterial(bukkitMaterial.name()));
+
+            assertFalse(returnedMaterials.containsKey(compatibleMaterial),
+                    () -> String.format("Assertion failed when converting Material.%s to CompatibleMaterial.%s: " +
+                                    "CompatibleMaterial.%1$s has already been returned for Material.%3$s previously",
+                            bukkitMaterial.name(),
+                            compatibleMaterial.name(),
+                            returnedMaterials.get(compatibleMaterial).name()
+                    ));
+
+            assertEquals(bukkitMaterial.isAir(), compatibleMaterial.isAir(), getMaterialPropertyAssertionError(compatibleMaterial, "Air"));
+            assertEquals(bukkitMaterial.isBlock(), compatibleMaterial.isBlock(), getMaterialPropertyAssertionError(compatibleMaterial, "Block"));
+            assertEquals(bukkitMaterial.isBurnable(), compatibleMaterial.isBurnable(), getMaterialPropertyAssertionError(compatibleMaterial, "Burnable"));
+            assertEquals(bukkitMaterial.isEdible(), compatibleMaterial.isEdible(), getMaterialPropertyAssertionError(compatibleMaterial, "Edible"));
+            assertEquals(bukkitMaterial.isFlammable(), compatibleMaterial.isFlammable(), getMaterialPropertyAssertionError(compatibleMaterial, "Flammable"));
+            assertEquals(bukkitMaterial.isFuel(), compatibleMaterial.isFuel(), getMaterialPropertyAssertionError(compatibleMaterial, "Fuel"));
+            assertEquals(bukkitMaterial.isInteractable(), compatibleMaterial.isInteractable(), getMaterialPropertyAssertionError(compatibleMaterial, "Interactable"));
+            assertEquals(bukkitMaterial.isItem(), compatibleMaterial.isItem(), getMaterialPropertyAssertionError(compatibleMaterial, "Item"));
+            assertEquals(bukkitMaterial.isOccluding(), compatibleMaterial.isOccluding(), getMaterialPropertyAssertionError(compatibleMaterial, "Occluding"));
+            assertEquals(bukkitMaterial.isSolid(), compatibleMaterial.isSolid(), getMaterialPropertyAssertionError(compatibleMaterial, "Solid"));
+            assertEquals(bukkitMaterial.isTransparent(), compatibleMaterial.isTransparent(), getMaterialPropertyAssertionError(compatibleMaterial, "Transparent"));
+
+            assertFalse(compatibleMaterial.usesCompatibility());
+            assertFalse(compatibleMaterial.usesData());
+            assertEquals(-1, compatibleMaterial.getData());
+
+            ItemStack compatibleItem = compatibleMaterial.getItem();
+            assertEquals(bukkitMaterial, compatibleItem.getType());
+            assertEquals(compatibleMaterial, CompatibleMaterial.getMaterial(compatibleItem));
+
+            returnedMaterials.put(compatibleMaterial, bukkitMaterial);
+        }
+    }
+
+    private Supplier<String> getMaterialPropertyAssertionError(CompatibleMaterial compatibleMaterial, String propertyName) {
+        return () -> String.format("Expected CompatibleMaterial.%s to be '%s'", compatibleMaterial.name(), propertyName);
+    }
+}