Python: Add Purview Middleware (#1142)

* [Py Purview] Purview Python Initial Commit

* [Py Purview] Purview Python Minor Fixes

* [Py Purview] Purview Python Comment Fixesish

* [Py Purview] Purview Python Agent Middleware Done

* [Py Purview] Purview Python Agent Middleware Done

* [Py Purview] Purview Python Lint Errors

* [Py Purview] Purview Python Final Hopefully

* [Py Purview] Purview Python Final Hopefully

* [Py Purview] Purview Python Fix ReadMe

* [Py Purview] Purview Python Fix MyPy

* [Py Purview] Purview Python Minor Updates on comments

* [Py Purview] Purview Python Fix Build Error

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Co-authored-by: Dmytro Struk <13853051+dmytrostruk@users.noreply.github.com>

python/packages/purview/tests/test_exceptions.py

@@ -0,0 +1,38 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Tests for Purview exceptions."""
+
+from agent_framework_purview import (
+    PurviewAuthenticationError,
+    PurviewRateLimitError,
+    PurviewRequestError,
+    PurviewServiceError,
+)
+
+
+class TestPurviewExceptions:
+    """Test custom Purview exception classes."""
+
+    def test_purview_service_error(self) -> None:
+        """Test PurviewServiceError base exception."""
+        error = PurviewServiceError("Service error occurred")
+        assert str(error) == "Service error occurred"
+        assert isinstance(error, Exception)
+
+    def test_purview_authentication_error(self) -> None:
+        """Test PurviewAuthenticationError exception."""
+        error = PurviewAuthenticationError("Authentication failed")
+        assert str(error) == "Authentication failed"
+        assert isinstance(error, PurviewServiceError)
+
+    def test_purview_rate_limit_error(self) -> None:
+        """Test PurviewRateLimitError exception."""
+        error = PurviewRateLimitError("Rate limit exceeded")
+        assert str(error) == "Rate limit exceeded"
+        assert isinstance(error, PurviewServiceError)
+
+    def test_purview_request_error(self) -> None:
+        """Test PurviewRequestError exception."""
+        error = PurviewRequestError("Request failed")
+        assert str(error) == "Request failed"
+        assert isinstance(error, PurviewServiceError)