diff --git a/test/test_iam.py b/test/test_iam.py
index 3315fb0..3980eea 100644
--- a/test/test_iam.py
+++ b/test/test_iam.py
@@ -675,3 +675,77 @@ async def test_delete_group_users_success(default_client: AsyncClient):
 	assert "group" in data
 	assert data["group"]["id"] == 1
 	assert data["group"]["name"] == "Org One Group"
+
+
+@pytest.mark.anyio
+async def test_put_group_user_invitation_success(default_client: AsyncClient):
+	body = {"user_email": "admin@test.com", "organisation_id": 1, "group_id": 1}
+	resp = await default_client.put("/iam/group/user/invitation", json=body)
+
+	assert resp.status_code == 200
+	data = resp.json()
+	assert "organisation" in data
+	assert isinstance(data["organisation"], dict)
+	assert data["organisation"]["id"] == 1
+	assert data["organisation"]["name"] == "Org One"
+
+	assert "invited_email" in data
+	assert isinstance(data["invited_email"], str)
+	assert data["invited_email"] == "admin@test.com"
+
+	assert "group" in data
+	assert isinstance(data["group"], dict)
+	assert data["group"]["name"] == "Org One Group"
+	assert data["group"]["id"] == 1
+
+
+@pytest.mark.parametrize(
+	"body, expected_status",
+	[
+		({"organisation_id": 42, "user_email": "admin@test.com", "group_id": 1}, 404),
+		(
+			{
+				"organisation_id": "Test Org",
+				"user_email": "admin@test.com",
+				"group_id": 1,
+			},
+			422,
+		),
+		({"organisation_id": "", "user_email": "admin@test.com", "group_id": 1}, 422),
+		({}, 422),
+		({"user_email": 42, "group_id": 1}, 422),
+		({"organisation_id": 1, "user_email": "Test User", "group_id": 1}, 422),
+		({"organisation_id": 1, "user_email": "admin@test.com", "group_id": 42}, 404),
+		({"organisation_id": "Test Org", "user_email": "admin@test.com"}, 422),
+		({"organisation_id": "", "user_email": "admin@test.com"}, 422),
+		({"user_email": 42}, 422),
+	],
+)
+@pytest.mark.anyio
+async def test_put_group_user_invitation_status_checks(
+	default_client: AsyncClient, body, expected_status
+):
+	resp = await default_client.put("/iam/group/user/invitation", json=body)
+
+	assert resp.status_code == expected_status
+
+
+@pytest.mark.parametrize(
+	"body, expected_status",
+	[
+		({"jwt": "invalid"}, 401),
+		({"jwt": ""}, 401),
+		({"jwt": None}, 422),
+		({"jwt": 42}, 422),
+	],
+)
+@pytest.mark.anyio
+async def test_put_group_user_invitation_accept_status_checks(
+	default_client: AsyncClient, body, expected_status
+):
+	resp = await default_client.put("/iam/group/user/invitation/accept", json=body)
+
+	assert resp.status_code == expected_status
+
+	if resp.status_code == 401:
+		assert resp.json()["detail"] == "Invalid JWS"