add WorkspaceUser tests from authz

tests/domain/test_workspace_users.py

@@ -0,0 +1,43 @@
+import pytest
+from uuid import uuid4
+
+from atst.domain.workspace_users import WorkspaceUsers
+from atst.domain.users import Users
+
+
+@pytest.fixture()
+def users_repo(db):
+    return Users(db)
+
+@pytest.fixture()
+def workspace_users_repo(db):
+    return WorkspaceUsers(db)
+
+def test_can_create_new_workspace_user(users_repo, workspace_users_repo):
+    workspace_id = uuid4()
+    user = users_repo.create(uuid4(), "developer")
+
+    workspace_user_dicts = [
+        {"id": user.id, "workspace_role": "owner"}
+    ]
+
+    workspace_users = workspace_users_repo.add_many(workspace_id, workspace_user_dicts)
+
+    assert workspace_users[0].user.id == user.id
+    assert workspace_users[0].user.atat_role.name == "developer"
+    assert workspace_users[0].workspace_role.role.name == "owner"
+
+
+def test_can_update_existing_workspace_user(users_repo, workspace_users_repo):
+    workspace_id = uuid4()
+    user = users_repo.create(uuid4(), "developer")
+
+    workspace_users_repo.add_many(workspace_id, [
+        {"id": user.id, "workspace_role": "owner"}
+    ])
+    workspace_users = workspace_users_repo.add_many(workspace_id, [
+        {"id": user.id, "workspace_role": "developer"}
+    ])
+
+    assert workspace_users[0].user.id == user.id
+    assert workspace_users[0].workspace_role.role.name == "developer"