diff --git a/tests/core/test_storage_core.py b/tests/core/test_storage_core.py
index 1827294..21de243 100644
--- a/tests/core/test_storage_core.py
+++ b/tests/core/test_storage_core.py
@@ -1,18 +1,77 @@
 import tempfile
 import os
+import threading
 
-from scrapling.core.storage import SQLiteStorageSystem
+from lxml.html import fromstring
+
+from scrapling.core.storage import SQLiteStorageSystem, StorageSystemMixin
+from scrapling.core.utils import _StorageTools
+
+
+class TestGetBaseUrl:
+    """Test StorageSystemMixin._get_base_url()"""
+
+    def _make_storage(self, url=None):
+        # Clear lru_cache between tests to avoid cross-test pollution
+        StorageSystemMixin._get_base_url.cache_clear()
+        return SQLiteStorageSystem(storage_file=":memory:", url=url)
+
+    def test_returns_default_when_url_is_none(self):
+        storage = self._make_storage(url=None)
+        assert storage._get_base_url() == "default"
+
+    def test_returns_default_when_url_is_empty(self):
+        storage = self._make_storage(url="")
+        assert storage._get_base_url() == "default"
+
+    def test_returns_fld_for_valid_url(self):
+        storage = self._make_storage(url="https://www.example.com/page")
+        result = storage._get_base_url()
+        assert result == "example.com"
+
+    def test_url_is_lowercased(self):
+        storage = self._make_storage(url="https://WWW.EXAMPLE.COM/Page")
+        assert storage.url == "https://www.example.com/page"
+
+
+class TestGetHash:
+    """Test StorageSystemMixin._get_hash()"""
+
+    def setup_method(self):
+        StorageSystemMixin._get_hash.cache_clear()
+
+    def test_deterministic_output(self):
+        h1 = StorageSystemMixin._get_hash("test-identifier")
+        h2 = StorageSystemMixin._get_hash("test-identifier")
+        assert h1 == h2
+
+    def test_different_input_different_output(self):
+        h1 = StorageSystemMixin._get_hash("identifier-a")
+        h2 = StorageSystemMixin._get_hash("identifier-b")
+        assert h1 != h2
+
+    def test_strips_and_lowercases(self):
+        h1 = StorageSystemMixin._get_hash("  Hello  ")
+        h2 = StorageSystemMixin._get_hash("hello")
+        assert h1 == h2
+
+    def test_includes_length_suffix(self):
+        result = StorageSystemMixin._get_hash("test")
+        # Format: {sha256_hex}_{byte_length}
+        assert "_" in result
+        hex_part, length_part = result.rsplit("_", 1)
+        assert len(hex_part) == 64  # SHA-256 hex length
+        assert length_part == str(len("test".encode("utf-8")))
 
 
 class TestSQLiteStorageSystem:
     """Test SQLiteStorageSystem functionality"""
-    
+
     def test_sqlite_storage_creation(self):
         """Test SQLite storage system creation"""
-        # Use an in-memory database for testing
         storage = SQLiteStorageSystem(storage_file=":memory:")
         assert storage is not None
-    
+
     def test_sqlite_storage_with_file(self):
         """Test SQLite storage with an actual file"""
         with tempfile.NamedTemporaryFile(suffix='.db', delete=False) as tmp_file:
@@ -24,18 +83,210 @@ class TestSQLiteStorageSystem:
             assert storage is not None
             assert os.path.exists(db_path)
         finally:
-            # Close the database connection before deleting (required on Windows)
             if storage is not None:
                 storage.close()
             if os.path.exists(db_path):
                 os.unlink(db_path)
-    
+
     def test_sqlite_storage_initialization_args(self):
         """Test SQLite storage with various initialization arguments"""
-        # Test with URL parameter
         storage = SQLiteStorageSystem(
             storage_file=":memory:",
             url="https://example.com"
         )
         assert storage is not None
         assert storage.url == "https://example.com"
+
+
+class TestSaveRetrieveRoundTrip:
+    """Test the save/retrieve round-trip — the core of the adaptive feature."""
+
+    def _make_storage(self, url="https://example.com"):
+        StorageSystemMixin._get_base_url.cache_clear()
+        SQLiteStorageSystem.cache_clear()
+        return SQLiteStorageSystem(storage_file=":memory:", url=url)
+
+    def _make_element(self, html_str="<div><p id='target' class='main'>Hello</p></div>"):
+        tree = fromstring(html_str)
+        return tree.cssselect("p")[0] if tree.cssselect("p") else tree
+
+    def test_save_and_retrieve(self):
+        storage = self._make_storage()
+        element = self._make_element()
+        storage.save(element, "test-element")
+
+        result = storage.retrieve("test-element")
+        assert result is not None
+        assert result["tag"] == "p"
+        assert result["attributes"]["id"] == "target"
+        assert result["attributes"]["class"] == "main"
+        assert result["text"] == "Hello"
+
+    def test_retrieve_nonexistent_returns_none(self):
+        storage = self._make_storage()
+        assert storage.retrieve("does-not-exist") is None
+
+    def test_save_overwrites_existing(self):
+        storage = self._make_storage()
+        elem1 = self._make_element("<div><p id='v1'>First</p></div>")
+        elem2 = self._make_element("<div><p id='v2'>Second</p></div>")
+
+        storage.save(elem1, "my-element")
+        storage.save(elem2, "my-element")
+
+        result = storage.retrieve("my-element")
+        assert result is not None
+        assert result["attributes"]["id"] == "v2"
+        assert result["text"] == "Second"
+
+    def test_url_isolation(self):
+        """Elements saved under one URL should not be retrievable under another."""
+        SQLiteStorageSystem.cache_clear()
+        StorageSystemMixin._get_base_url.cache_clear()
+
+        # Use file-based storage so both instances share the same DB
+        with tempfile.NamedTemporaryFile(suffix='.db', delete=False) as tmp:
+            db_path = tmp.name
+
+        try:
+            storage_a = SQLiteStorageSystem(storage_file=db_path, url="https://site-a.com")
+            element = self._make_element()
+            storage_a.save(element, "shared-id")
+
+            SQLiteStorageSystem.cache_clear()
+            StorageSystemMixin._get_base_url.cache_clear()
+
+            storage_b = SQLiteStorageSystem(storage_file=db_path, url="https://site-b.com")
+            assert storage_b.retrieve("shared-id") is None
+        finally:
+            storage_a.close()
+            storage_b.close()
+            if os.path.exists(db_path):
+                os.unlink(db_path)
+
+    def test_element_path_is_stored(self):
+        storage = self._make_storage()
+        element = self._make_element("<html><body><div><p>Text</p></div></body></html>")
+        storage.save(element, "path-test")
+
+        result = storage.retrieve("path-test")
+        assert result is not None
+        assert "path" in result
+        # Path should be a list of tag names from root to element
+        assert result["path"][-1] == "p"
+
+    def test_element_without_parent(self):
+        """A root element (no parent) should still be savable."""
+        storage = self._make_storage()
+        tree = fromstring("<div>Root element</div>")
+        storage.save(tree, "root-elem")
+
+        result = storage.retrieve("root-elem")
+        assert result is not None
+        assert "parent_name" not in result
+
+    def test_element_with_children_and_siblings(self):
+        storage = self._make_storage()
+        html_str = "<div><p>Sibling</p><span id='target'><b>Child</b><i>Child2</i></span></div>"
+        tree = fromstring(html_str)
+        element = tree.cssselect("#target")[0]
+        storage.save(element, "with-children")
+
+        result = storage.retrieve("with-children")
+        assert result is not None
+        assert "children" in result
+        assert "b" in result["children"]
+        assert "i" in result["children"]
+        assert "siblings" in result
+        assert "p" in result["siblings"]
+
+
+class TestStorageThreadSafety:
+    """Test that SQLiteStorageSystem is safe under concurrent access."""
+
+    def test_concurrent_saves(self):
+        SQLiteStorageSystem.cache_clear()
+        StorageSystemMixin._get_base_url.cache_clear()
+
+        with tempfile.NamedTemporaryFile(suffix='.db', delete=False) as tmp:
+            db_path = tmp.name
+
+        storage = SQLiteStorageSystem(storage_file=db_path, url="https://example.com")
+        errors = []
+
+        def save_element(idx):
+            try:
+                html_str = f"<div><p id='elem-{idx}'>Text {idx}</p></div>"
+                tree = fromstring(html_str)
+                element = tree.cssselect("p")[0]
+                storage.save(element, f"element-{idx}")
+            except Exception as e:
+                errors.append(e)
+
+        threads = [threading.Thread(target=save_element, args=(i,)) for i in range(20)]
+        for t in threads:
+            t.start()
+        for t in threads:
+            t.join()
+
+        assert len(errors) == 0, f"Thread safety errors: {errors}"
+
+        # Verify all elements were saved
+        for i in range(20):
+            result = storage.retrieve(f"element-{i}")
+            assert result is not None, f"element-{i} not found after concurrent save"
+
+        storage.close()
+        if os.path.exists(db_path):
+            os.unlink(db_path)
+
+
+class TestStorageToolsElementToDict:
+    """Test _StorageTools.element_to_dict() directly."""
+
+    def test_basic_element(self):
+        tree = fromstring("<div><p class='foo'>Hello</p></div>")
+        elem = tree.cssselect("p")[0]
+        result = _StorageTools.element_to_dict(elem)
+
+        assert result["tag"] == "p"
+        assert result["attributes"]["class"] == "foo"
+        assert result["text"] == "Hello"
+        assert "parent_name" in result
+        assert result["parent_name"] == "div"
+
+    def test_element_no_text(self):
+        tree = fromstring("<div><p class='empty'></p></div>")
+        elem = tree.cssselect("p")[0]
+        result = _StorageTools.element_to_dict(elem)
+        assert result["text"] is None
+
+    def test_element_no_attributes(self):
+        tree = fromstring("<div><p>Plain</p></div>")
+        elem = tree.cssselect("p")[0]
+        result = _StorageTools.element_to_dict(elem)
+        assert result["attributes"] == {}
+
+    def test_element_strips_whitespace_attributes(self):
+        tree = fromstring('<div><p data-val="  "></p></div>')
+        elem = tree.cssselect("p")[0]
+        result = _StorageTools.element_to_dict(elem)
+        # Whitespace-only attribute values should be filtered out
+        assert "data-val" not in result["attributes"]
+
+
+class TestStorageToolsGetElementPath:
+    """Test _StorageTools._get_element_path()."""
+
+    def test_nested_path(self):
+        tree = fromstring("<html><body><div><p>Text</p></div></body></html>")
+        elem = tree.cssselect("p")[0]
+        path = _StorageTools._get_element_path(elem)
+        assert path[-1] == "p"
+        assert "div" in path
+        assert "body" in path
+
+    def test_root_element_path(self):
+        tree = fromstring("<div>Root</div>")
+        path = _StorageTools._get_element_path(tree)
+        assert path == ("div",)