PluginManagerTest: Ensure config keyNames are not duplicated

This adds a new test to ensure plugin configurations do not duplicate
the keyName annotation argument to prevent runtime errors.

runelite-client/src/test/java/net/runelite/client/plugins/PluginManagerTest.java

@@ -38,6 +38,7 @@ import java.applet.Applet;
 import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
@@ -48,6 +49,8 @@ import net.runelite.api.Client;
 import net.runelite.client.RuneLite;
 import net.runelite.client.RuneLiteModule;
 import net.runelite.client.eventbus.EventBus;
+import net.runelite.client.config.Config;
+import net.runelite.client.config.ConfigItem;
 import net.runelite.client.rs.ClientUpdateCheckMode;
 import static org.junit.Assert.assertEquals;
 import org.junit.Before;
@@ -75,6 +78,7 @@ public class PluginManagerTest
 	public Client client;
 
 	private Set<Class> pluginClasses;
+	private Set<Class> configClasses;
 
 	@Before
 	public void before() throws IOException
@@ -85,8 +89,9 @@ public class PluginManagerTest
 
 		RuneLite.setInjector(injector);
 
-		// Find plugins we expect to have
+		// Find plugins and configs we expect to have
 		pluginClasses = new HashSet<>();
+		configClasses = new HashSet<>();
 		Set<ClassInfo> classes = ClassPath.from(getClass().getClassLoader()).getTopLevelClassesRecursive(PLUGIN_PACKAGE);
 		for (ClassInfo classInfo : classes)
 		{
@@ -95,6 +100,12 @@ public class PluginManagerTest
 			if (pluginDescriptor != null)
 			{
 				pluginClasses.add(clazz);
+				continue;
+			}
+
+			if (Config.class.isAssignableFrom(clazz))
+			{
+				configClasses.add(clazz);
 			}
 		}
 
@@ -155,4 +166,37 @@ public class PluginManagerTest
 		}
 	}
 
+	@Test
+	public void ensureNoDuplicateConfigKeyNames()
+	{
+		for (final Class clazz : configClasses)
+		{
+			final Set<String> configKeyNames = new HashSet<>();
+
+			for (final Method method : clazz.getMethods())
+			{
+				if (!method.isDefault())
+				{
+					continue;
+				}
+
+				final ConfigItem annotation = method.getAnnotation(ConfigItem.class);
+
+				if (annotation == null)
+				{
+					continue;
+				}
+
+				final String configKeyName = annotation.keyName();
+
+				if (configKeyNames.contains(configKeyName))
+				{
+					throw new IllegalArgumentException("keyName " + configKeyName + " is duplicated in " + clazz);
+				}
+
+				configKeyNames.add(configKeyName);
+			}
+		}
+	}
+
 }