The quantlib timeseries suite added on 2026-08-06 calls functions that
lazy-import statsmodels, but CI installs only ".[dev,openbb]", so all 56
statsmodels-dependent tests failed with the ImportError those functions
raise by design. Two-sided fix, following the openbb precedent already in
the workflow: CI now installs ".[dev,openbb,stats]" and fails loudly if
statsmodels or arch stops resolving, and the 41 statsmodels-dependent
tests (plus the tool-envelope test that reaches compute_half_life) carry
a skip guard so a base install reports skips instead of failures. The
missing-dependency error-path tests still run exactly where they should:
only in an environment without the extra.
Haozhe Wu
a1bb7ac029