feat: add test connection functionality for proxy hosts and enhance UI for testing connections

backend/internal/database/database_test.go

@@ -1,22 +1,29 @@
 package database
 
 import (
-"path/filepath"
-"testing"
+	"path/filepath"
+	"testing"
 
-"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestConnect(t *testing.T) {
-// Test with memory DB
-db, err := Connect("file::memory:?cache=shared")
-assert.NoError(t, err)
-assert.NotNil(t, db)
+	// Test with memory DB
+	db, err := Connect("file::memory:?cache=shared")
+	assert.NoError(t, err)
+	assert.NotNil(t, db)
 
-// Test with file DB
-tempDir := t.TempDir()
-dbPath := filepath.Join(tempDir, "test.db")
-db, err = Connect(dbPath)
-assert.NoError(t, err)
-assert.NotNil(t, db)
+	// Test with file DB
+	tempDir := t.TempDir()
+	dbPath := filepath.Join(tempDir, "test.db")
+	db, err = Connect(dbPath)
+	assert.NoError(t, err)
+	assert.NotNil(t, db)
+}
+
+func TestConnect_Error(t *testing.T) {
+	// Test with invalid path (directory)
+	tempDir := t.TempDir()
+	_, err := Connect(tempDir)
+	assert.Error(t, err)
 }