diff --git a/CHANGES.md b/CHANGES.md
index 2373142..9d6ee02 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -3,7 +3,7 @@
 ## 0.10 (unreleased)
 
 
-- Nothing changed yet.
+- Added gmw/gmn/upload/import
 
 
 ## 0.9 (2024-04-23)
diff --git a/api/tests/test_bro_import.py b/api/tests/test_bro_import.py
index c8a1dcc..3fc86e2 100644
--- a/api/tests/test_bro_import.py
+++ b/api/tests/test_bro_import.py
@@ -1,8 +1,8 @@
 import pytest
 from django.conf import settings
-from requests.exceptions import RequestException
+from requests.exceptions import HTTPError, RequestException
 
-from api.bro_import import bulk_import
+from api.bro_import import bulk_import, object_import
 from api.tests import fixtures
 
 organisation = fixtures.organisation
@@ -44,3 +44,63 @@ def test_fetch_bro_ids_fail(mocker, bulk_importer):
 
     with pytest.raises(bulk_import.FetchBROIDsError):
         bulk_importer._fetch_bro_ids("url.com")
+
+
+@pytest.fixture
+def gmn_object_importer(organisation):
+    return object_import.GMNObjectImporter(
+        bro_domain="GMN", bro_id="GMN1234567890", data_owner=organisation.uuid
+    )
+
+
+@pytest.mark.django_db
+def test_object_importer_create_download_url(gmn_object_importer):
+    url = gmn_object_importer._create_download_url()
+
+    assert (
+        url
+        == f"{settings.BRO_UITGIFTE_SERVICE_URL}/gm/gmn/v1/objects/GMN1234567890?fullHistory=nee"
+    )
+
+
+@pytest.mark.django_db
+def test_object_importer_download_xml(mocker, gmn_object_importer):
+    expected_content = b"<xml>fake_data</xml>"
+    mock_get = mocker.patch("requests.get")
+    mock_response = mocker.Mock()
+    mock_response.raise_for_status = mocker.Mock()
+    mock_response.content = expected_content
+    mock_get.return_value = mock_response
+
+    # Test
+    url = "https://example.com/data.xml"
+    result = gmn_object_importer._download_xml(url)
+
+    # Assert
+    assert result == expected_content
+
+
+@pytest.mark.django_db
+def test_download_xml_http_error(mocker, gmn_object_importer):
+    # Setup
+    mock_get = mocker.patch("requests.get")
+    mock_response = mocker.Mock()
+    mock_response.raise_for_status.side_effect = HTTPError("Error occurred")
+    mock_get.return_value = mock_response
+
+    # Test
+    url = "https://example.com/data.xml"
+
+    # Assert that an HTTPError is raised
+    with pytest.raises(HTTPError):
+        gmn_object_importer._download_xml(url)
+
+
+@pytest.mark.django_db
+def test_convert_xml_to_json(gmn_object_importer):
+    xml = b"<xml>fake_data</xml>"
+    expected_json = {"xml": "fake_data"}
+
+    json_data = gmn_object_importer._convert_xml_to_json(xml)
+
+    assert json_data == expected_json
diff --git a/api/tests/test_bro_upload.py b/api/tests/test_bro_upload.py
index 309fe33..1b38aa7 100644
--- a/api/tests/test_bro_upload.py
+++ b/api/tests/test_bro_upload.py
@@ -1,6 +1,6 @@
 import pytest
 
-from api.bro_upload import delivery
+from api.bro_upload import delivery, utils
 
 expected_xml_str = """<registrationRequest xmlns="http://www.broservices.nl/xsd/isgmn/1.0"
     xmlns:brocom="http://www.broservices.nl/xsd/brocommon/3.0"
@@ -94,3 +94,38 @@ def test_xml_generator2():
             sourcedocs_data={},
         )
         generator.create_xml_file()
+
+
+def test_simlify_validation_errors():
+    input_data = [
+        {
+            "type": "missing",
+            "loc": ["requestReference"],
+            "msg": "Field required",
+            "input": {},
+            "url": "https://errors.pydantic.dev/2.7/v/missing",
+        },
+        {
+            "type": "missing",
+            "loc": ["deliveryAccountableParty"],
+            "msg": "Field required",
+            "input": {},
+            "url": "https://errors.pydantic.dev/2.7/v/missing",
+        },
+        {
+            "type": "missing",
+            "loc": ["qualityRegime"],
+            "msg": "Field required",
+            "input": {},
+            "url": "https://errors.pydantic.dev/2.7/v/missing",
+        },
+    ]
+    expected_output = {
+        "requestReference": "Field required",
+        "deliveryAccountableParty": "Field required",
+        "qualityRegime": "Field required",
+    }
+
+    output = utils.simplify_validation_errors(input_data)
+
+    assert output == expected_output
diff --git a/gmn/tests/test_gmn_serializers.py b/gmn/tests/test_gmn_serializers.py
new file mode 100644
index 0000000..acb041e
--- /dev/null
+++ b/gmn/tests/test_gmn_serializers.py
@@ -0,0 +1,37 @@
+from datetime import date, datetime
+
+import pytest
+
+from api.tests import fixtures
+from gmn import serializers
+
+# this setup is chosen because ruff removes the fixture imports in other methods
+organisation = fixtures.organisation
+gmn = fixtures.gmn
+gmw = fixtures.gmw
+
+
+@pytest.mark.django_db
+def test_gmn_serialization(gmn):
+    serializer = serializers.GMNSerializer(instance=gmn)
+    assert serializer.data["bro_id"] == gmn.bro_id
+
+
+@pytest.mark.django_db
+def test_gmn_deserialization(gmn, organisation):
+    input_data = {
+        "data_owner": organisation.uuid,
+        "bro_id": "GMN123456789",
+        "delivery_accountable_party": "12345678",
+        "quality_regime": "IMBRO",
+        "name": "test",
+        "delivery_context": "test",
+        "monitoring_purpose": "test",
+        "groundwater_aspect": "test",
+        "start_date_monitoring": date(2000, 1, 1),
+        "object_registration_time": datetime(2000, 1, 1),
+        "registration_status": "test",
+        "color": "#000fff",
+    }
+    serializer = serializers.GMNSerializer(data=input_data)
+    assert serializer.is_valid(), serializer.errors
diff --git a/gmw/tests/test_gmw_serializers.py b/gmw/tests/test_gmw_serializers.py
new file mode 100644
index 0000000..d9d2848
--- /dev/null
+++ b/gmw/tests/test_gmw_serializers.py
@@ -0,0 +1,14 @@
+import pytest
+
+from api.tests import fixtures
+from gmw import serializers
+
+# this setup is chosen because ruff removes the fixture imports in other methods
+organisation = fixtures.organisation
+gmw = fixtures.gmw
+
+
+@pytest.mark.django_db
+def test_gmw_serialization(gmw):
+    serializer = serializers.GMWSerializer(instance=gmw)
+    assert serializer.data["bro_id"] == gmw.bro_id