Basics for testing block level bus stuff.

build.gradle

@@ -75,7 +75,7 @@ dependencies {
     compileOnly fg.deobf("mezz.jei:jei-${minecraft_version}:9.1.0.41:api")
     runtimeOnly fg.deobf("mezz.jei:jei-${minecraft_version}:9.1.0.41")
 
-    testImplementation 'org.mockito:mockito-core:4.3.1'
+    testImplementation 'org.mockito:mockito-inline:4.3.1'
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.2'
 }

src/test/java/li/cil/oc2/common/bus/BlockBusTests.java

@@ -0,0 +1,160 @@
+/* SPDX-License-Identifier: MIT */
+
+package li.cil.oc2.common.bus;
+
+import li.cil.oc2.api.bus.DeviceBusElement;
+import li.cil.oc2.common.capabilities.Capabilities;
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.LevelAccessor;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraftforge.common.capabilities.Capability;
+import net.minecraftforge.common.util.LazyOptional;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+
+import java.util.HashMap;
+import java.util.HashSet;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.*;
+
+public class BlockBusTests {
+    @SuppressWarnings("unchecked") private static final Capability<DeviceBusElement> DEVICE_BUS_ELEMENT_CAPABILITY = (Capability<DeviceBusElement>) mock(Capability.class);
+
+    private FakeLevel fakeLevel;
+    private LevelAccessor level;
+    private MockedStatic<Capabilities> capabilitiesMock;
+
+    @BeforeEach
+    public void setupEach() {
+        fakeLevel = new FakeLevel();
+        level = fakeLevel.getLevel();
+        capabilitiesMock = mockStatic(Capabilities.class);
+        capabilitiesMock.when(Capabilities::deviceBusElement).thenReturn(DEVICE_BUS_ELEMENT_CAPABILITY);
+    }
+
+    @AfterEach
+    public void teardownEach() {
+        capabilitiesMock.close();
+    }
+
+    @Test
+    public void busTouchingUnloadedChunkStaysIncomplete() {
+        final BlockDeviceBusController busController = createBusController(new BlockPos(0, 0, 0));
+
+        busController.scan();
+
+        assertEquals(CommonDeviceBusController.BusState.INCOMPLETE, busController.getState());
+    }
+
+    @Test
+    public void busNotTouchingUnloadedChunkCompletes() {
+        final BlockDeviceBusController busController = createBusController(new BlockPos(8, 0, 8));
+
+        busController.scan();
+
+        assertEquals(CommonDeviceBusController.BusState.READY, busController.getState());
+    }
+
+    @Test
+    public void busControllerDetectsBusElements() {
+        final BlockDeviceBusController busController = createBusController(new BlockPos(8, 0, 8));
+
+        final DeviceBusElement busElement = createBusElement(new BlockPos(9, 0, 8));
+
+        busController.scan();
+
+        assertEquals(CommonDeviceBusController.BusState.READY, busController.getState());
+
+        assertTrue(busElement.getControllers().contains(busController));
+        assertTrue(busController.getElements().contains(busElement));
+    }
+
+    private BlockDeviceBusController createBusController(final BlockPos pos) {
+        final TestBlockDeviceBusElement busElement = new TestBlockDeviceBusElement(level, pos);
+        final BlockEntity blockEntity = mock(BlockEntity.class);
+        when(blockEntity.getBlockPos()).thenReturn(pos);
+        when(blockEntity.getCapability(any(), any())).thenReturn(LazyOptional.empty());
+        final BlockDeviceBusController busController = new BlockDeviceBusController(busElement, 0, blockEntity);
+
+        fakeLevel.addBlockEntity(blockEntity);
+        fakeLevel.setChunkLoaded(new ChunkPos(pos), true);
+
+        return busController;
+    }
+
+    private AbstractBlockDeviceBusElement createBusElement(final BlockPos pos) {
+        final TestBlockDeviceBusElement busElement = new TestBlockDeviceBusElement(level, pos);
+        final BlockEntity blockEntity = mock(BlockEntity.class);
+        when(blockEntity.getBlockPos()).thenReturn(pos);
+        when(blockEntity.getCapability(any(), any())).thenReturn(LazyOptional.empty());
+        when(blockEntity.getCapability(eq(Capabilities.deviceBusElement()), any())).thenReturn(LazyOptional.of(() -> busElement));
+
+        fakeLevel.addBlockEntity(blockEntity);
+        fakeLevel.setChunkLoaded(new ChunkPos(pos), true);
+
+        return busElement;
+    }
+
+    private static final class FakeLevel {
+        private final LevelAccessor level = mock(LevelAccessor.class);
+        private final HashMap<BlockPos, BlockEntity> blockEntities = new HashMap<>();
+        private final HashSet<ChunkPos> loadedChunks = new HashSet<>();
+
+        public FakeLevel() {
+            when(level.getBlockEntity(any())).then(a -> blockEntities.get(a.<BlockPos>getArgument(0)));
+
+            when(level.hasChunk(anyInt(), anyInt())).then(a -> {
+                final int chunkX = a.getArgument(0);
+                final int chunkZ = a.getArgument(1);
+                return loadedChunks.contains(new ChunkPos(chunkX, chunkZ));
+            });
+        }
+
+        public LevelAccessor getLevel() {
+            return level;
+        }
+
+        public void addBlockEntity(final BlockEntity blockEntity) {
+            blockEntities.put(blockEntity.getBlockPos(), blockEntity);
+        }
+
+        public void removeBlockEntity(final BlockPos pos) {
+            blockEntities.remove(pos);
+        }
+
+        public void setChunkLoaded(final ChunkPos chunkPos, final boolean loaded) {
+            if (loaded) {
+                loadedChunks.add(chunkPos);
+            } else {
+                loadedChunks.remove(chunkPos);
+            }
+        }
+    }
+
+    private static final class TestBlockDeviceBusElement extends AbstractBlockDeviceBusElement {
+        private final LevelAccessor level;
+        private final BlockPos blockPos;
+
+        public TestBlockDeviceBusElement(final LevelAccessor level, final BlockPos blockPos) {
+            this.level = level;
+            this.blockPos = blockPos;
+        }
+
+        @Override
+        public LevelAccessor getLevel() {
+            return level;
+        }
+
+        @Override
+        public BlockPos getPosition() {
+            return blockPos;
+        }
+    }
+}