diff --git a/tests/unit/test_http/test_api/test_errors.py b/tests/unit/test_http/test_api/test_errors.py
new file mode 100644
index 0000000..72114bb
--- /dev/null
+++ b/tests/unit/test_http/test_api/test_errors.py
@@ -0,0 +1,99 @@
+from unittest.mock import AsyncMock
+
+import httpx
+import pytest
+
+from enapter.http.api.errors import Error, MultiError, check_error
+
+
+@pytest.mark.asyncio
+async def test_check_error_success():
+    """Test that check_error does nothing when response is successful."""
+    response = httpx.Response(
+        status_code=200, request=httpx.Request("GET", "https://example.com")
+    )
+    await check_error(response)
+
+
+@pytest.mark.asyncio
+async def test_check_error_non_json():
+    """Test that check_error calls raise_for_status when response is not JSON."""
+    response = httpx.Response(
+        status_code=500,
+        content=b"Internal Server Error",
+        request=httpx.Request("GET", "https://example.com"),
+    )
+    with pytest.raises(httpx.HTTPStatusError):
+        await check_error(response)
+
+
+@pytest.mark.asyncio
+async def test_check_error_api_error_single():
+    """Test that check_error raises a single Error when one is present in DTO."""
+    dto = {
+        "errors": [
+            {
+                "message": "Device not found",
+                "code": "DEVICE_NOT_FOUND",
+                "details": {"device_id": "test_device"},
+            }
+        ]
+    }
+    response = httpx.Response(
+        status_code=404, json=dto, request=httpx.Request("GET", "https://example.com")
+    )
+    with pytest.raises(Error) as exc_info:
+        await check_error(response)
+
+    assert exc_info.value.message == "Device not found"
+    assert exc_info.value.code == "DEVICE_NOT_FOUND"
+    assert exc_info.value.details == {"device_id": "test_device"}
+
+
+@pytest.mark.asyncio
+async def test_check_error_api_error_multiple():
+    """Test that check_error raises MultiError when multiple are present in DTO."""
+    dto = {
+        "errors": [
+            {"message": "Invalid parameter A", "code": "INVALID_PARAM"},
+            {"message": "Invalid parameter B", "code": "INVALID_PARAM"},
+        ]
+    }
+    response = httpx.Response(
+        status_code=400, json=dto, request=httpx.Request("GET", "https://example.com")
+    )
+    with pytest.raises(MultiError) as exc_info:
+        await check_error(response)
+
+    assert len(exc_info.value.errors) == 2
+    assert exc_info.value.errors[0].message == "Invalid parameter A"
+    assert exc_info.value.errors[1].message == "Invalid parameter B"
+
+
+def test_error_from_dto_empty():
+    """Test Error.from_dto with minimal fields."""
+    err = Error.from_dto({})
+    assert err.message == "<no message>"
+    assert err.code is None
+    assert err.details is None
+
+
+def test_multi_error_from_dto_empty_list():
+    """Test MultiError.from_dto raises ValueError on empty error list."""
+    with pytest.raises(ValueError, match="empty error list"):
+        MultiError.from_dto({"errors": []})
+
+
+@pytest.mark.asyncio
+async def test_check_error_reads_body():
+    """Test that check_error reads the response body."""
+    response = httpx.Response(
+        status_code=500,
+        content=b"Internal Server Error",
+        request=httpx.Request("GET", "https://example.com"),
+    )
+    response.aread = AsyncMock()
+    with pytest.raises(httpx.HTTPStatusError):
+        await check_error(response)
+
+    response.aread.assert_awaited_once()