update warning (#1184)

* update warning

* update changelog number

* unittest

Author: Defiantearth

changes/1184.changed

@@ -0,0 +1 @@
+Deferred the missing python-magic warning in pysnow to only emit when attachment upload is attempted, rather than at import time.

nautobot_ssot/integrations/servicenow/third_party/pysnow/attachment.py

@@ -9,10 +9,6 @@
     HAS_MAGIC = True
 except ImportError:  # pragma: no cover
     HAS_MAGIC = False
-    warnings.warn(
-        "Missing the python-magic library; attachment content-type will be set to text/plain. "
-        "Try installing the python-magic-bin package if running on Mac or Windows"
-    )
 
 from .exceptions import InvalidUsage
 
@@ -68,7 +64,14 @@ def upload(self, sys_id, file_path, name=None, multipart=False):
             headers["Content-Type"] = "multipart/form-data"
             path_append = "/upload"
         else:
-            headers["Content-Type"] = magic.from_file(file_path, mime=True) if HAS_MAGIC else "text/plain"
+            if HAS_MAGIC:
+                headers["Content-Type"] = magic.from_file(file_path, mime=True)
+            else:
+                warnings.warn(
+                    "Missing the python-magic library; attachment content-type will be set to text/plain. "
+                    "Try installing the python-magic-bin package if running on Mac or Windows"
+                )
+                headers["Content-Type"] = "text/plain"
             path_append = "/file"
 
         return resource.request(method="POST", data=data, headers=headers, path_append=path_append)

nautobot_ssot/tests/servicenow/test_pysnow.py

@@ -0,0 +1,45 @@
+"""Unit tests for the pysnow module."""
+
+import warnings
+from unittest.mock import MagicMock, mock_open, patch
+
+from nautobot.core.testing import TestCase
+
+from nautobot_ssot.integrations.servicenow.third_party.pysnow.attachment import Attachment
+
+
+class TestAttachmentUploadContentType(TestCase):
+    """Test that the upload method sets Content-Type based on HAS_MAGIC."""
+
+    def setUp(self):
+        """Set up a minimal Attachment instance with a mocked resource."""
+        self.resource = MagicMock()
+        self.attachment = Attachment(resource=self.resource, table_name="incident")
+
+    @patch("nautobot_ssot.integrations.servicenow.third_party.pysnow.attachment.HAS_MAGIC", True)
+    @patch("nautobot_ssot.integrations.servicenow.third_party.pysnow.attachment.magic", create=True)
+    @patch("builtins.open", mock_open(read_data=b"file content"))
+    def test_upload_uses_magic_when_available(self, mock_magic):
+        """When python-magic is available, Content-Type should be determined by magic."""
+        file_path = "/tmp/test.pdf"
+        mock_magic.from_file.return_value = "application/pdf"
+
+        self.attachment.upload(sys_id="abc123", file_path=file_path)
+
+        mock_magic.from_file.assert_called_once_with(file_path, mime=True)
+        call_kwargs = self.resource.request.call_args[1]
+        self.assertEqual(call_kwargs["headers"]["Content-Type"], "application/pdf")
+
+    @patch("nautobot_ssot.integrations.servicenow.third_party.pysnow.attachment.HAS_MAGIC", False)
+    @patch("builtins.open", mock_open(read_data=b"file content"))
+    def test_upload_falls_back_to_text_plain_without_magic(self):
+        """When python-magic is missing, Content-Type should fall back to text/plain with a warning."""
+        with warnings.catch_warnings(record=True) as caught_warnings:
+            warnings.simplefilter("always")
+            self.attachment.upload(sys_id="abc123", file_path="/tmp/test.txt")
+
+        self.assertEqual(len(caught_warnings), 1)
+        self.assertIn("python-magic", str(caught_warnings[0].message))
+
+        call_kwargs = self.resource.request.call_args[1]
+        self.assertEqual(call_kwargs["headers"]["Content-Type"], "text/plain")