test: guard source-only consumer reflection contracts

src/test/java/codechicken/multipart/ConsumerReflectionCompatibilityTest.java

@@ -0,0 +1,75 @@
+package codechicken.multipart;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+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.assertTrue;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.Arrays;
+
+import net.minecraft.block.Block;
+
+import org.junit.jupiter.api.Test;
+
+import codechicken.microblock.BlockMicroMaterial;
+import codechicken.microblock.ItemSaw;
+import codechicken.microblock.MicroMaterialRegistry;
+import codechicken.microblock.MicroMaterialRegistry.IMicroMaterial;
+import codechicken.multipart.minecraft.ButtonPart;
+import cpw.mods.fml.relauncher.ReflectionHelper;
+
+/** Source-only compatibility contracts used by optional integrations in the target pack. */
+class ConsumerReflectionCompatibilityTest {
+
+    @Test
+    void guideNhMixinCanTargetBlockMicroMaterialFields() throws NoSuchFieldException {
+        Field block = field(BlockMicroMaterial.class, "block", Block.class);
+        Field meta = field(BlockMicroMaterial.class, "meta", int.class);
+
+        assertFalse(Modifier.isStatic(block.getModifiers()));
+        assertFalse(Modifier.isStatic(meta.getModifiers()));
+    }
+
+    @Test
+    void etFuturumCanReplaceButtonOrientationArrays() {
+        Field metaSideMap = ReflectionHelper.findField(ButtonPart.class, "metaSideMap");
+        Field sideMetaMap = ReflectionHelper.findField(ButtonPart.class, "sideMetaMap");
+
+        assertMutableStaticIntArray(metaSideMap);
+        assertMutableStaticIntArray(sideMetaMap);
+    }
+
+    @Test
+    void iguanaCanFindTheSawHarvestLevel() throws NoSuchFieldException {
+        Field harvestLevel = field(ItemSaw.class, "harvestLevel", int.class);
+
+        assertFalse(Modifier.isStatic(harvestLevel.getModifiers()));
+    }
+
+    @Test
+    void galacticraftNameOnlyLookupFindsOneCompatibleRegistrationMethod() throws NoSuchMethodException {
+        Method[] methods = Arrays.stream(MicroMaterialRegistry.class.getMethods())
+                .filter(method -> method.getName().equals("registerMaterial")).toArray(Method[]::new);
+
+        assertEquals(1, methods.length, "Galacticraft invokes the first public method with this name");
+        assertTrue(Modifier.isStatic(methods[0].getModifiers()));
+        assertArrayEquals(new Class<?>[] { IMicroMaterial.class, String.class }, methods[0].getParameterTypes());
+        assertNotNull(BlockMicroMaterial.class.getConstructor(Block.class, int.class));
+    }
+
+    private static Field field(Class<?> owner, String name, Class<?> type) throws NoSuchFieldException {
+        Field field = owner.getDeclaredField(name);
+        assertEquals(type, field.getType());
+        return field;
+    }
+
+    private static void assertMutableStaticIntArray(Field field) {
+        assertEquals(int[].class, field.getType());
+        assertTrue(Modifier.isStatic(field.getModifiers()));
+        assertFalse(Modifier.isFinal(field.getModifiers()));
+    }
+}