chore: use a dataclass to return values from `prepare_send_data`

I found the tuple of three values confusing. So instead use a
dataclass to return the three values. It is still confusing but a
little bit less so.

Also add some unit tests

2 files changed, 38 insertions, 0 deletions

diff --git a/tests/unit/_backends/__init__.py b/tests/unit/_backends/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/unit/_backends/__init__.py
diff --git a/tests/unit/_backends/test_requests_backend.py b/tests/unit/_backends/test_requests_backend.py
new file mode 100644
index 0000000..d83703d
--- /dev/null
+++ b/tests/unit/_backends/test_requests_backend.py
@@ -0,0 +1,38 @@
+import pytest
+from requests_toolbelt.multipart.encoder import MultipartEncoder  # type: ignore
+
+from gitlab._backends import requests_backend
+
+
+class TestSendData:
+    def test_senddata_json(self) -> None:
+        result = requests_backend.SendData(
+            json={"a": 1}, content_type="application/json"
+        )
+        assert result.data is None
+
+    def test_senddata_data(self) -> None:
+        result = requests_backend.SendData(
+            data={"b": 2}, content_type="application/octet-stream"
+        )
+        assert result.json is None
+
+    def test_senddata_json_and_data(self) -> None:
+        with pytest.raises(ValueError, match=r"json={'a': 1}  data={'b': 2}"):
+            requests_backend.SendData(
+                json={"a": 1}, data={"b": 2}, content_type="application/json"
+            )
+
+
+class TestRequestsBackend:
+    def test_prepare_send_data_str_parentid(self) -> None:
+        file = "12345"
+        files = {"file": ("file.tar.gz", file, "application/octet-stream")}
+        post_data = {"parent_id": "12"}
+
+        result = requests_backend.RequestsBackend.prepare_send_data(
+            files=files, post_data=post_data, raw=False
+        )
+        assert result.json is None
+        assert result.content_type.startswith("multipart/form-data")
+        assert isinstance(result.data, MultipartEncoder)