test: enforce full GeigerCounters coverage and fix collection regressions

.github/workflows/build.yml

@@ -70,3 +70,11 @@ jobs:
           name: unit-test-reports-${{ github.run_id }}-${{ github.run_attempt }}
           path: target/surefire-reports/
           if-no-files-found: error
+
+      - name: Upload coverage reports
+        if: ${{ !cancelled() && hashFiles('target/site/jacoco/jacoco.xml') != '' }}
+        uses: actions/upload-artifact@v7
+        with:
+          name: coverage-reports-${{ github.run_id }}-${{ github.run_attempt }}
+          path: target/site/jacoco/
+          if-no-files-found: error

README.md

@@ -23,6 +23,14 @@ Originally created by [Justinas Launikonis](https://github.com/JustinasLa).
 
 Technical documentation is maintained in [TF-Minecraft/Docs](https://github.com/TF-Minecraft/Docs).
 
+## Tests
+
+With Java 21 and the pinned plugin dependencies installed, run `mvn clean verify`.
+Tests use JUnit, Mockito, and MockBukkit; JaCoCo reports are written to
+`target/site/jacoco/index.html` and uploaded by CI. Tests run locally without a live
+Minecraft server. Verification requires 100% line, branch, and instruction
+coverage of production code, with no coverage exclusions.
+
 ## License
 
 Copyright (c) 2026 TF-Minecraft contributors.

pom.xml

@@ -18,6 +18,24 @@
     </properties>
 
     <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.10.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>5.20.0</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockbukkit.mockbukkit</groupId>
+            <artifactId>mockbukkit-v1.21</artifactId>
+            <version>4.95.0</version>
+            <scope>test</scope>
+        </dependency>
         <!-- Paper API -->
         <dependency>
             <groupId>io.papermc.paper</groupId>
@@ -89,6 +107,55 @@
             </resource>
         </resources>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.5.4</version>
+            </plugin>
+            <plugin>
+                <groupId>org.jacoco</groupId>
+                <artifactId>jacoco-maven-plugin</artifactId>
+                <version>0.8.15</version>
+                <executions>
+                    <execution>
+                        <goals><goal>prepare-agent</goal></goals>
+                    </execution>
+                    <execution>
+                        <id>coverage-report</id>
+                        <phase>verify</phase>
+                        <goals><goal>report</goal></goals>
+                    </execution>
+                    <execution>
+                        <id>coverage-check</id>
+                        <phase>verify</phase>
+                        <goals><goal>check</goal></goals>
+                        <configuration>
+                            <rules>
+                                <rule>
+                                    <element>BUNDLE</element>
+                                    <limits>
+                                        <limit>
+                                            <counter>INSTRUCTION</counter>
+                                            <value>COVEREDRATIO</value>
+                                            <minimum>1.0</minimum>
+                                        </limit>
+                                        <limit>
+                                            <counter>LINE</counter>
+                                            <value>COVEREDRATIO</value>
+                                            <minimum>1.0</minimum>
+                                        </limit>
+                                        <limit>
+                                            <counter>BRANCH</counter>
+                                            <value>COVEREDRATIO</value>
+                                            <minimum>1.0</minimum>
+                                        </limit>
+                                    </limits>
+                                </rule>
+                            </rules>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>

src/main/java/net/tfminecraft/geigercounters/commands/GeigerCommand.java

@@ -103,6 +103,9 @@ private void handleMove(CommandSender sender, String[] args) {
         try {
             x = Double.parseDouble(args[1]);
             z = Double.parseDouble(args[2]);
+            if (!Double.isFinite(x) || !Double.isFinite(z)) {
+                throw new NumberFormatException("Coordinates must be finite");
+            }
         } catch (NumberFormatException e) {
             sender.sendMessage(messages().get("admin.move-invalid-coords"));
             return;

src/main/java/net/tfminecraft/geigercounters/config/ConfigMigrator.java

@@ -116,7 +116,8 @@ public void migrate() {
     // ====================================
     private void migrateMessages() {
         File messagesFile = new File(plugin.getDataFolder(), MESSAGES_FILE);
-        if (!messagesFile.exists()) {
+        boolean createdMessagesFile = !messagesFile.exists();
+        if (createdMessagesFile) {
             plugin.saveResource(MESSAGES_FILE, false);
         }
 
@@ -135,7 +136,11 @@ private void migrateMessages() {
                 if (oldSection.isConfigurationSection(key)) {
                     continue;
                 }
-                messages.set(key, oldSection.get(key));
+                // A newly installed file already contains player.* defaults.
+                // Legacy custom wording must replace those shipped values.
+                String destination = createdMessagesFile && List.of(LEGACY_ROOT_MESSAGES).contains(key)
+                    ? "player." + key : key;
+                messages.set(destination, oldSection.get(key));
                 moved.add(key);
             }
 
@@ -262,12 +267,12 @@ private YamlConfiguration loadPackagedConfig() {
     }
 
     private YamlConfiguration loadPackagedYaml(String resource) {
-        try (InputStream stream = plugin.getResource(resource)) {
-            if (stream == null) {
-                plugin.getLogger().warning("No " + resource + " packaged in the jar - skipping its migration.");
-                return null;
-            }
-
+        InputStream stream = plugin.getResource(resource);
+        if (stream == null) {
+            plugin.getLogger().warning("No " + resource + " packaged in the jar - skipping its migration.");
+            return null;
+        }
+        try (stream) {
             try (Reader reader = new InputStreamReader(stream, StandardCharsets.UTF_8)) {
                 return YamlConfiguration.loadConfiguration(reader);
             }

src/main/java/net/tfminecraft/geigercounters/config/GeigerConfiguration.java

@@ -197,7 +197,7 @@ private void loadSoundSettings() {
     // onto the same event once lowercased, since the enum name is the event ID
     // with dots turned into underscores.
     private String normalizeSoundName(String raw) {
-        if (raw == null || raw.trim().isEmpty()) {
+        if (raw.trim().isEmpty()) {
             return DEFAULT_SOUND;
         }
 

src/main/java/net/tfminecraft/geigercounters/config/Messages.java

@@ -75,10 +75,11 @@ public static String coordinate(double value) {
     }
 
     private YamlConfiguration loadPackaged() {
-        try (InputStream stream = plugin.getResource(ConfigMigrator.MESSAGES_FILE)) {
-            if (stream == null) {
-                return null;
-            }
+        InputStream stream = plugin.getResource(ConfigMigrator.MESSAGES_FILE);
+        if (stream == null) {
+            return null;
+        }
+        try (stream) {
             try (Reader reader = new InputStreamReader(stream, StandardCharsets.UTF_8)) {
                 return YamlConfiguration.loadConfiguration(reader);
             }

src/main/java/net/tfminecraft/geigercounters/handlers/SourceHandler.java

@@ -104,7 +104,7 @@ private void attemptRandomPlacement(int attempt, CompletableFuture<Location> res
         loadChunkFor(x, z).whenComplete((chunk, error) -> {
             // Paper completes chunk futures on the main thread, so everything
             // below is safe to run against the world directly
-            if (!plugin.isEnabled()) {
+            if (pendingMove != result || !plugin.isEnabled()) {
                 result.complete(null);
                 return;
             }
@@ -141,11 +141,12 @@ private void attemptRandomPlacement(int attempt, CompletableFuture<Location> res
     // filter check is logged so the admin knows the spot is normally excluded
     // ====================================
     public CompletableFuture<Location> moveSourceToLocation(double x, double z) {
+        sourceLocation = null;
         CompletableFuture<Location> result = new CompletableFuture<>();
         pendingMove = result;
 
         loadChunkFor(x, z).whenComplete((chunk, error) -> {
-            if (!plugin.isEnabled()) {
+            if (pendingMove != result || !plugin.isEnabled()) {
                 result.complete(null);
                 return;
             }
@@ -207,6 +208,18 @@ public void tryCollectSource(Player player, double distance, EquipmentSlot geige
             return;
         }
 
+        // Callers may hold a distance from before another player's collection.
+        // Validate against the current source, including its world, before consuming it.
+        Location playerLocation = player.getLocation();
+        if (!sourceLocation.getWorld().equals(playerLocation.getWorld())) {
+            return;
+        }
+        double deltaX = playerLocation.getX() - sourceLocation.getX();
+        double deltaZ = playerLocation.getZ() - sourceLocation.getZ();
+        if (Math.hypot(deltaX, deltaZ) > config.getCollectionDistance()) {
+            return;
+        }
+
         // Player is out of collections for this window - the source stays put
         // so somebody else can still claim it
         if (!dropLimits.canCollect(player)) {
@@ -255,17 +268,26 @@ private void notifyPlayerOfCollection(Player player) {
     }
 
     private void replaceGeigerWithDeadVersion(Player player, EquipmentSlot geigerSlot) {
-        // Remove active Geiger Counter from whichever hand held it
-        if (geigerSlot == EquipmentSlot.OFF_HAND) {
-            player.getInventory().setItemInOffHand(null);
+        // Consume one counter, preserving any others stacked in the same hand.
+        boolean offHand = geigerSlot == EquipmentSlot.OFF_HAND;
+        ItemStack active = offHand ? player.getInventory().getItemInOffHand()
+            : player.getInventory().getItemInMainHand();
+        ItemStack remaining = null;
+        if (active.getAmount() > 1) {
+            remaining = active.clone();
+            remaining.setAmount(active.getAmount() - 1);
+        }
+        if (offHand) {
+            player.getInventory().setItemInOffHand(remaining);
         } else {
-            player.getInventory().setItemInMainHand(null);
+            player.getInventory().setItemInMainHand(remaining);
         }
 
         // Give dead Geiger Counter
         try {
             ItemStack deadGeiger = api.getCreator().getItemFromPath(DEAD_GEIGER_PATH).clone();
-            player.getInventory().addItem(deadGeiger);
+            deadGeiger.setAmount(1);
+            giveItemOrDropLeftovers(player, deadGeiger);
             player.playSound(player.getLocation(), Sound.ENTITY_ITEM_BREAK, 1f, 1f);
             player.sendMessage(config.getMessages().get("player.dead-geiger"));
         } catch (Exception e) {
@@ -284,7 +306,7 @@ private void giveReward(Player player) {
 
         // Select a tier based on weights
         TierReward selectedTier = selectRandomTier(tiers);
-        if (selectedTier == null || selectedTier.isEmpty()) {
+        if (selectedTier.isEmpty()) {
             return;
         }
 
@@ -312,15 +334,16 @@ private TierReward selectRandomTier(List<TierReward> tiers) {
 
         // Find which tier this value falls into
         double cumulativeWeight = 0.0;
-        for (TierReward tier : tiers) {
+        for (int index = 0; index < tiers.size() - 1; index++) {
+            TierReward tier = tiers.get(index);
             cumulativeWeight += tier.getWeight();
             if (randomValue <= cumulativeWeight) {
                 return tier;
             }
         }
-        
-        // Fallback to last tier (shouldnt happen but why not)
-        return tiers.get(tiers.size() - 1);
+
+        // Every remaining draw selects the final tier, including rounding fallback.
+        return tiers.getLast();
     }
 
     // ====================================
@@ -329,13 +352,19 @@ private TierReward selectRandomTier(List<TierReward> tiers) {
     private void giveRewardItem(Player player, ItemReward reward, String tierName) {
         try {
             ItemStack rewardItem = createRewardItem(reward);
-            player.getInventory().addItem(rewardItem);
+            giveItemOrDropLeftovers(player, rewardItem);
             plugin.getLogger().info(player.getName() + " received " + tierName + " reward: " + reward.getOutputItem());
         } catch (Exception e) {
             plugin.getLogger().warning("Failed to give reward to " + player.getName() + ": " + e.getMessage());
         }
     }
 
+    private void giveItemOrDropLeftovers(Player player, ItemStack item) {
+        for (ItemStack leftover : player.getInventory().addItem(item).values()) {
+            player.getWorld().dropItemNaturally(player.getLocation(), leftover);
+        }
+    }
+
     // ====================================
     // Create an ItemStack for the reward
     // ====================================

src/main/java/net/tfminecraft/geigercounters/hooks/WorldGuardHook.java

@@ -1,6 +1,6 @@
 package net.tfminecraft.geigercounters.hooks;
 
-import com.sk89q.worldedit.bukkit.BukkitAdapter;
+import com.sk89q.worldedit.bukkit.BukkitWorld;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldguard.WorldGuard;
 import com.sk89q.worldguard.protection.managers.RegionManager;
@@ -30,7 +30,7 @@ public boolean isInAnyRegion(Location location, Set<String> regionIds) {
         RegionManager regions = WorldGuard.getInstance()
             .getPlatform()
             .getRegionContainer()
-            .get(BukkitAdapter.adapt(location.getWorld()));
+            .get(new BukkitWorld(location.getWorld()));
 
         if (regions == null) {
             return false;

src/main/java/net/tfminecraft/geigercounters/managers/DropLimitManager.java

@@ -14,6 +14,7 @@
 import java.util.Deque;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.UUID;
 
@@ -91,19 +92,22 @@ public int getRemaining(UUID playerId) {
 
     // ====================================
     // Millis until the next collection slot frees up, or 0 if one is free.
-    // That is the oldest stamp in the window plus the window length.
+    // If the configured limit was lowered, enough stamps must expire to
+    // bring the retained count below the new limit.
     // ====================================
     public long getMillisUntilNextDrop(UUID playerId) {
-        if (getRemaining(playerId) > 0) {
+        if (!config.isLimitEnabled() || getRemaining(playerId) > 0) {
             return 0L;
         }
 
+        // Enabled limits are positive; zero remaining guarantees a nonempty history.
         Deque<Long> stamps = collections.get(playerId);
-        if (stamps == null || stamps.isEmpty()) {
-            return 0L;
+        Iterator<Long> timestamps = stamps.iterator();
+        long nextSlot = timestamps.next();
+        for (int excess = stamps.size() - config.getLimitDrops(); excess > 0; excess--) {
+            nextSlot = timestamps.next();
         }
-
-        long readyAt = stamps.peekFirst() + config.getLimitWindowMillis();
+        long readyAt = nextSlot + config.getLimitWindowMillis();
         return Math.max(0L, readyAt - System.currentTimeMillis());
     }
 

src/main/java/net/tfminecraft/geigercounters/managers/GeigerManager.java

@@ -141,12 +141,15 @@ private void startClickTask() {
     // in either hand
     // ====================================
     private void checkAllPlayers() {
-        Location source = sourceHandler.getSourceLocation();
-        if (source == null) {
-            return;
-        }
-
         for (Player player : Bukkit.getOnlinePlayers()) {
+            // A preceding player can collect and relocate the source immediately.
+            Location source = sourceHandler.getSourceLocation();
+            if (source == null) {
+                return;
+            }
+            if (!player.getLocation().getWorld().equals(source.getWorld())) {
+                continue;
+            }
             EquipmentSlot geigerSlot = findGeigerSlot(player);
 
             if (geigerSlot != null) {