Codecov flagged 17 uncovered lines in
crates/wickra-core/src/indicators/bollinger_bandwidth.rs (file at 79.51%):
- the const accessors period (54-56), multiplier (59-61), value (64-66)
- the zero-middle defensive fallback 0.0 (line 77) inside update
- the Indicator-impl bodies warmup_period (90-92) and name (98-100)
- the unreachable `_ => panic!("warmup mismatch")` arm (line 140) in
the existing matches_bands_definition test
None of the existing tests inspected the metadata surface — every test
fed numeric updates and asserted on bandwidth values, leaving the five
getter bodies dead. The zero-middle path was unreachable because all
existing tests used positive price levels ≈100, so the rolling SMA was
always strictly positive and the divide-by-zero guard never fired.
The panic arm in matches_bands_definition was an invariant guard that
by design cannot fire when the two streams share a warmup period; that
invariant is now asserted directly with assert_eq!(w.is_some(),
b.is_some()), and the catch-all arm is gone.
Add two new tests and refactor one existing:
- accessors_and_metadata asserts period == 20, multiplier == 2.0,
value() == None before warmup, warmup_period == 20, name ==
"BollingerBandwidth", then drives 20 updates so value() also
exercises the Some branch.
- zero_middle_band_yields_zero_bandwidth feeds [-2, -1, 0, 1, 2] so
the 5-bar SMA lands on exactly 0.0 at the fifth input, and asserts
the emitted bandwidth is exactly 0.0 (rather than inf/nan from the
would-be divide-by-zero).
- matches_bands_definition now uses an explicit assert_eq! on
is_some() agreement plus an if let for the numeric compare,
removing the unreachable panic arm without weakening the
invariant check.
bollinger_bandwidth.rs is now at 83/83 lines, no behavioural change.
kingchenc
050e5b74b8