test: add async response headers integration tests

Author: drish

tests/async_response_headers_test.py

@@ -0,0 +1,169 @@
+from unittest.mock import AsyncMock
+
+import pytest
+
+import resend
+
+
+pytestmark = pytest.mark.asyncio
+
+
+class TestResponseHeadersIntegrationAsync:
+    def setup_method(self) -> None:
+        resend.api_key = "re_test_key"
+
+    async def test_email_send_async_response_includes_http_headers(self) -> None:
+        """Test that async email send response includes http_headers."""
+        mock_client = AsyncMock()
+        mock_client.request.return_value = (
+            b'{"id": "email_123"}',
+            200,
+            {
+                "content-type": "application/json",
+                "x-request-id": "req_abc123",
+                "x-ratelimit-limit": "100",
+                "x-ratelimit-remaining": "95",
+                "x-ratelimit-reset": "1699564800",
+            },
+        )
+
+        original_client = resend.default_async_http_client
+        resend.default_async_http_client = mock_client
+
+        try:
+            response = await resend.Emails.send_async(
+                {
+                    "from": "test@example.com",
+                    "to": "user@example.com",
+                    "subject": "Test",
+                    "html": "<p>Test</p>",
+                }
+            )
+
+            assert isinstance(response, dict)
+            assert response["id"] == "email_123"
+            assert "http_headers" in response
+            assert response["http_headers"]["x-request-id"] == "req_abc123"
+            assert response["http_headers"]["x-ratelimit-limit"] == "100"
+            assert response["http_headers"]["x-ratelimit-remaining"] == "95"
+            assert response["http_headers"]["x-ratelimit-reset"] == "1699564800"
+
+        finally:
+            resend.default_async_http_client = original_client
+
+    async def test_list_async_response_includes_http_headers(self) -> None:
+        """Test that async list responses include http_headers."""
+        mock_client = AsyncMock()
+        mock_client.request.return_value = (
+            b'{"data": [{"id": "key_1"}, {"id": "key_2"}]}',
+            200,
+            {
+                "content-type": "application/json",
+                "x-request-id": "req_xyz",
+            },
+        )
+
+        original_client = resend.default_async_http_client
+        resend.default_async_http_client = mock_client
+
+        try:
+            response = await resend.ApiKeys.list_async()
+
+            assert isinstance(response, dict)
+            assert "data" in response
+            assert "http_headers" in response
+            assert response["http_headers"]["x-request-id"] == "req_xyz"
+
+        finally:
+            resend.default_async_http_client = original_client
+
+    async def test_received_email_async_headers_not_overwritten_by_http_headers(
+        self,
+    ) -> None:
+        """
+        Regression test: ReceivedEmail.headers (MIME email headers) must not be
+        overwritten by the injected http_headers (API response headers).
+        """
+        mock_client = AsyncMock()
+        mock_client.request.return_value = (
+            b'{"id": "email_456", "object": "received_email", '
+            b'"from": "sender@example.com", "to": ["recipient@example.com"], '
+            b'"subject": "Hello", "created_at": "2024-01-01T00:00:00Z", '
+            b'"message_id": "msg_123", "attachments": [], '
+            b'"headers": {"List-Unsubscribe": "<mailto:unsub@example.com>", '
+            b'"X-Custom": "value"}}',
+            200,
+            {
+                "content-type": "application/json",
+                "x-request-id": "req_recv_123",
+                "x-ratelimit-limit": "100",
+            },
+        )
+
+        original_client = resend.default_async_http_client
+        resend.default_async_http_client = mock_client
+
+        try:
+            response = await resend.Emails.Receiving.get_async(
+                email_id="email_456"
+            )
+
+            assert isinstance(response, dict)
+            assert response["id"] == "email_456"
+
+            # MIME email headers must be intact
+            assert "headers" in response
+            assert response["headers"]["List-Unsubscribe"] == "<mailto:unsub@example.com>"
+            assert response["headers"]["X-Custom"] == "value"
+
+            # HTTP response headers must be injected separately under http_headers
+            assert "http_headers" in response
+            assert response["http_headers"]["x-request-id"] == "req_recv_123"
+            assert response["http_headers"]["x-ratelimit-limit"] == "100"
+
+            # The two must not collide
+            assert response["headers"] is not response["http_headers"]
+
+        finally:
+            resend.default_async_http_client = original_client
+
+    async def test_send_async_with_custom_email_headers_does_not_collide(
+        self,
+    ) -> None:
+        """
+        Test that SendParams.headers (custom email headers sent to the recipient)
+        do not collide with http_headers in the response.
+        """
+        mock_client = AsyncMock()
+        mock_client.request.return_value = (
+            b'{"id": "email_789"}',
+            200,
+            {
+                "content-type": "application/json",
+                "x-request-id": "req_789",
+            },
+        )
+
+        original_client = resend.default_async_http_client
+        resend.default_async_http_client = mock_client
+
+        try:
+            response = await resend.Emails.send_async(
+                {
+                    "from": "test@example.com",
+                    "to": "user@example.com",
+                    "subject": "Test",
+                    "html": "<p>Test</p>",
+                    "headers": {"List-Unsubscribe": "<mailto:unsub@example.com>"},
+                }
+            )
+
+            assert isinstance(response, dict)
+            assert response["id"] == "email_789"
+            # SendResponse does not echo back SendParams.headers — only id is returned
+            assert "headers" not in response
+            assert "http_headers" in response
+            assert response["http_headers"]["x-request-id"] == "req_789"
+
+        finally:
+            resend.default_async_http_client = original_client