Exclude clientsettings.xml from "last save" search in MekHQ

MekHQ/src/mekhq/gui/panels/StartupScreenPanel.java

@@ -53,7 +53,7 @@ public class StartupScreenPanel extends AbstractMHQPanel {
     private BufferedImage backgroundIcon;
 
     // Save file filtering needs to avoid loading some special files
-    public FilenameFilter saveFilter = new FilenameFilter() {
+    static public FilenameFilter saveFilter = new FilenameFilter() {
         @Override
         public boolean accept(File dir, String name) {
             // Allow any .xml, .cpnx, and .cpnx.gz file that is not in the list of excluded files

MekHQ/unittests/mekhq/gui/panels/StartupScreenPanelTest.java

@@ -0,0 +1,37 @@
+package mekhq.gui.panels;
+
+import megamek.common.preference.PreferenceManager;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import static org.mockito.Mockito.*;
+
+import java.io.File;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StartupScreenPanelTest {
+    File dir;
+
+    @BeforeEach
+    void setUp() {
+        dir = mock(File.class);
+    }
+
+    @Test
+    void testSaveFilterAllowsValidCampaignSaves(){
+        String fileName = "MySave.xml";
+        assertTrue(StartupScreenPanel.saveFilter.accept(dir, fileName));
+        fileName = "MySave.CPNX";
+        assertTrue(StartupScreenPanel.saveFilter.accept(dir, fileName));
+        fileName = "20240306T2344 Save Campaign No 666.cpnx.gz";
+        assertTrue(StartupScreenPanel.saveFilter.accept(dir, fileName));
+    }
+
+    @Test
+    void testSaveFilterNotAllowClientSettingsXML(){
+        String fileName = PreferenceManager.DEFAULT_CFG_FILE_NAME.toLowerCase();
+        boolean allowed = StartupScreenPanel.saveFilter.accept(dir, fileName);
+        assertFalse(allowed);
+    }
+}