diff --git a/swh/scanner/tests/conftest.py b/swh/scanner/tests/conftest.py
--- a/swh/scanner/tests/conftest.py
+++ b/swh/scanner/tests/conftest.py
@@ -38,19 +38,38 @@
 
 
 @pytest.fixture(scope='session')
-def temp_paths(tmp_path_factory):
-    """Fixture to generate temporary paths"""
-    subpath = tmp_path_factory.getbasetemp()
+def temp_folder(tmp_path_factory):
+    """Fixture that generate a temporary folder with the following
+    structure:
+
+    root: {
+        subdir: {
+            filesample.txt
+        }
+        subdir2
+        subfile.txt
+    }
+    """
+    root = tmp_path_factory.getbasetemp()
     subdir = tmp_path_factory.mktemp('subdir')
     subdir2 = tmp_path_factory.mktemp('subdir2')
-    subfile = subpath.joinpath(PosixPath('./subfile.txt'))
+    subfile = root.joinpath(PosixPath('./subfile.txt'))
     subfile.touch()
+    filesample = subdir.joinpath(PosixPath('./filesample.txt'))
+    filesample.touch()
 
-    avail_path = [subdir, subdir2, subfile]
-    avail_pid = [pid_of_dir(bytes(subdir)), pid_of_dir(bytes(subdir2)),
-                 pid_of_file(bytes(subfile))]
+    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 {'paths': avail_path, 'pids': avail_pid}
+    return {
+        'root': root,
+        'paths': avail_path,
+        'filesample': filesample
+    }
 
 
 @pytest.fixture(scope='session')
@@ -62,6 +81,7 @@
 
 @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()
diff --git a/swh/scanner/tests/test_model.py b/swh/scanner/tests/test_model.py
--- a/swh/scanner/tests/test_model.py
+++ b/swh/scanner/tests/test_model.py
@@ -2,3 +2,66 @@
 # 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']
diff --git a/swh/scanner/tests/test_scanner.py b/swh/scanner/tests/test_scanner.py
--- a/swh/scanner/tests/test_scanner.py
+++ b/swh/scanner/tests/test_scanner.py
@@ -47,10 +47,13 @@
            pids_discovery(request, aiosession, api_url))
 
 
-def test_scanner_get_subpaths(tmp_path, temp_paths):
+def test_scanner_get_subpaths(temp_folder, tmp_path):
+    paths = temp_folder['paths'].keys()
+    pids = temp_folder['paths'].values()
+
     for subpath, pid in get_subpaths(tmp_path):
-        assert subpath in temp_paths['paths']
-        assert pid in temp_paths['pids']
+        assert subpath in paths
+        assert pid in pids
 
 
 @pytest.mark.options(debug=False)