Add Python SDK unit tests and fix get_host_top_protocols TypeError

[Copilot]

The Python SDK (python/ntopng/) had zero unit tests — only a manual integration script requiring a live server. The Lua timeseries test suite covered just two cases, leaving calculateMinMax, calculateStatistics, ninetififthPercentile, and edge cases of upsampleSerie entirely untested.

Python SDK — 86 new unit tests (python/tests/test_ntopng_sdk.py)

Uses unittest.mock to test all four SDK classes offline (no ntopng instance needed):

• Ntopng — constructor auth modes (token vs user+pass), connection/content-type failure, request/post_request success and HTTP-error paths, all getter methods, URL construction
• Interface — all data, alert, flow, L4/L7 endpoints; get_host/get_historical factory methods; get_all_alerts with and without IP filter
• Host — get_host_data, get_l7_stats, get_dscp_stats (both directions), get_active_flows_paginated, VLAN propagation
• Historical — all nine alert-family delegate methods, timeseries schema/query building, timeseries_to_pandas (valid and missing-key responses), get_flows (POST), top conversations/protocols

Bug fix — historical.py get_host_top_protocols

Tests uncovered a runtime TypeError: self.ifid (an int) was concatenated directly with strings:

# Before — crashes at runtime
"ts_query": "ifid:" + self.ifid + ",host:" + host

# After
"ts_query": "ifid:" + str(self.ifid) + ",host:" + host

Lua — 11 new ts_common test cases (ts_common_test.lua)

Covers previously untested ts_common.lua functions:

• upsampleSerie: no-op when target ≤ source length, empty series
• calculateMinMax: ascending sequence, single element, NaN-skipping
• calculateStatistics: counter type (total×step), gauge+keep_total, gauge without total, NaN-skipping
• ninetififthPercentile: single element, all-NaN series

The new module is registered in run.lua.

To fix an unused import, remove only the unused name from the import statement while preserving the used ones. This eliminates the unnecessary dependency and resolves the static analysis warning without changing behavior.

In python/tests/test_ntopng_sdk.py, on line 11, change from unittest.mock import MagicMock, patch, call to import only MagicMock and patch, since those are used in _make_mock_response and _make_ntopng, while call is not referenced. No additional methods or imports are needed; we simply adjust the existing import line.