feat: add populated test database and directory helper functions

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/tests/common/test_helpers.rs

@@ -144,3 +144,42 @@ pub fn assert_file_exists(file_path: &PathBuf) {
 pub fn assert_file_not_exists(file_path: &PathBuf) {
     assert!(!file_path.exists(), "File {:?} should not exist but it does", file_path);
 }
+
+/// Create a temporary database and populate it with sample data for testing
+pub fn create_populated_test_db() -> (TempDir, Connection, PathBuf) {
+    let (temp_dir, conn, db_path) = create_temp_db();
+    
+    // Insert some sample items
+    for i in 1..=5 {
+        let item = crate::db::Item {
+            id: None,
+            ts: chrono::Utc::now(),
+            size: Some(i * 100),
+            compression: if i % 2 == 0 {
+                crate::compression_engine::CompressionType::LZ4.to_string()
+            } else {
+                crate::compression_engine::CompressionType::GZip.to_string()
+            },
+        };
+        db::insert_item(&conn, item).expect("Failed to insert item");
+    }
+    
+    (temp_dir, conn, db_path)
+}
+
+/// Assert that a directory exists and is actually a directory
+pub fn assert_directory_exists(dir_path: &PathBuf) {
+    assert!(dir_path.exists(), "Directory {:?} does not exist", dir_path);
+    assert!(dir_path.is_dir(), "Path {:?} exists but is not a directory", dir_path);
+}
+
+/// Create a nested directory structure for testing
+pub fn create_nested_temp_dir_structure(dir: &TempDir) -> (PathBuf, PathBuf, PathBuf) {
+    let level1 = dir.path().join("level1");
+    let level2 = level1.join("level2");
+    let level3 = level2.join("level3");
+    
+    std::fs::create_dir_all(&level3).expect("Failed to create nested directory structure");
+    
+    (level1, level2, level3)
+}