diff --git a/swh/scanner/tests/conftest.py b/swh/scanner/tests/conftest.py
index 3457704..de9c89a 100644
--- a/swh/scanner/tests/conftest.py
+++ b/swh/scanner/tests/conftest.py
@@ -1,88 +1,90 @@
 # Copyright (C) 2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import pytest
 import asyncio
 import aiohttp
 import os
 from pathlib import PosixPath
 from aioresponses import aioresponses  # type: ignore
 
 from swh.model.cli import pid_of_file, pid_of_dir
 from .flask_api import create_app
 
 
 @pytest.fixture
 def mock_aioresponse():
     with aioresponses() as m:
         yield m
 
 
 @pytest.fixture
 def event_loop():
     """Fixture that generate an asyncio event loop."""
     loop = asyncio.new_event_loop()
     asyncio.set_event_loop(loop)
     yield loop
     loop.close()
 
 
 @pytest.fixture
 async def aiosession():
     """Fixture that generate an aiohttp Client Session."""
     session = aiohttp.ClientSession()
     yield session
     session.detach()
 
 
 @pytest.fixture(scope='session')
 def temp_folder(tmp_path_factory):
-    """Fixture that generate a temporary folder with the following
+    """Fixture that generates a temporary folder with the following
     structure:
 
-    root: {
-        subdir: {
-            filesample.txt
+    .. code-block:: python
+
+        root = {
+            subdir: {
+                filesample.txt
+            }
+            subdir2
+            subfile.txt
         }
-        subdir2
-        subfile.txt
-    }
     """
     root = tmp_path_factory.getbasetemp()
     subdir = tmp_path_factory.mktemp('subdir')
     subdir2 = tmp_path_factory.mktemp('subdir2')
-    subfile = root.joinpath(PosixPath('./subfile.txt'))
+    subfile = root / 'subfile.txt'
     subfile.touch()
-    filesample = subdir.joinpath(PosixPath('./filesample.txt'))
+    filesample = subdir / 'filesample.txt'
     filesample.touch()
 
     avail_path = {
         subdir: pid_of_dir(bytes(subdir)),
         subdir2: pid_of_dir(bytes(subdir2)),
         subfile: pid_of_file(bytes(subfile)),
         filesample: pid_of_file(bytes(filesample))
         }
 
     return {
         'root': root,
         'paths': avail_path,
         'filesample': filesample
     }
 
 
 @pytest.fixture(scope='session')
 def app():
     """Flask backend API (used by live_server)."""
     app = create_app()
     return app
 
 
 @pytest.fixture
 def test_folder():
     """Location of the "data" folder """
     tests_path = PosixPath(os.path.abspath(__file__)).parent
     tests_data_folder = tests_path.joinpath('data')
     assert tests_data_folder.exists()
     return tests_data_folder
diff --git a/swh/scanner/tests/test_model.py b/swh/scanner/tests/test_model.py
index 45208eb..5e4eee2 100644
--- a/swh/scanner/tests/test_model.py
+++ b/swh/scanner/tests/test_model.py
@@ -1,4 +1,67 @@
 # Copyright (C) 2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
+
+import pytest
+
+from swh.scanner.model import Tree
+
+
+@pytest.fixture(scope='function')
+def example_tree(temp_folder):
+    """Fixture that generate a Tree with the root present in the
+    session fixture "temp_folder".
+    """
+    example_tree = Tree(temp_folder['root'])
+    assert example_tree.path == temp_folder['root']
+
+    return example_tree
+
+
+def test_tree_add_node(example_tree, temp_folder):
+    avail_paths = temp_folder['paths'].keys()
+
+    for path, pid in temp_folder['paths'].items():
+        example_tree.addNode(path, pid)
+
+    for path, node in example_tree.children.items():
+        assert path in avail_paths
+        if node.children:
+            for subpath, subnode in node.children.items():
+                assert subpath in avail_paths
+
+
+def test_get_json_tree_all_not_present(example_tree, temp_folder):
+    for path, pid in temp_folder['paths'].items():
+        example_tree.addNode(path)
+
+    json_tree = example_tree.getJsonTree()
+
+    assert len(json_tree) == 0
+
+
+def test_get_json_tree_all_present(example_tree, temp_folder):
+    for path, pid in temp_folder['paths'].items():
+        example_tree.addNode(path, pid)
+
+    tree_dict = example_tree.getJsonTree()
+
+    assert len(tree_dict) == 3
+    # since subdir have a pid, it can't have a children path
+    assert tree_dict['subdir0'] is not dict
+
+
+def test_get_json_tree_only_one_present(example_tree, temp_folder):
+    filesample_path = temp_folder['filesample']
+
+    for path, pid in temp_folder['paths'].items():
+        if path == filesample_path:
+            example_tree.addNode(path, pid)
+        else:
+            example_tree.addNode(path)
+
+    tree_dict = example_tree.getJsonTree()
+
+    assert len(tree_dict) == 1
+    assert tree_dict['subdir0']['filesample.txt']