`bynk.observe.*` errors

Observation — expect Cap.op called … and the trace(Cap.op) escape hatch — asserts over a unit’s interaction with its capabilities (v0.117). These are their common errors. See the Observation reference.

bynk.observe.not_a_seam

[bynk.observe.not_a_seam] Error: `AuthId` is not a capability the unit under test consumes; only a consumed capability's calls can be observed

Cause: the observation subject is not a capability the unit consumes / has in scope via given — for example a type, a service, or a consumed-context alias.

Fix: observe a capability the unit actually depends on. Only injected capability seams record calls; a cross-context service or an agent handler is not (yet) observable.

bynk.observe.unknown_op

[bynk.observe.unknown_op] Error: capability `Logger` has no operation named `nope`

Cause: the Cap.op subject names an operation the capability does not declare.

Fix: use one of the capability’s declared operations (check the capability block).

bynk.observe.with_not_bool

[bynk.observe.with_not_bool] Error: a `with` predicate has type `String`, but a `Bool` is required

Cause: a with predicate does not evaluate to Bool.

Fix: make it a boolean claim over the operation’s parameters — a comparison (with amount > 1000), an is narrowing (with msg is "…"), or a pure Bool-returning method.

bynk.observe.impure_with

[bynk.observe.impure_with] Error: a `with` predicate uses an effectful or test-only construct; it must be pure

Cause: a with predicate uses an effect, ? propagation, expect, Val, or trace — a with predicate is the one predicate surface and must be pure.

Fix: remove the effectful/test-only construct. A with predicate may read the operation’s arguments and call pure value methods only.

An observation outside a case

An expect Cap.op called … observation is an expect, so outside a test body it is rejected as one (bynk.expect.outside_case): calls are recorded per case, so there is nothing to observe elsewhere. Move the observation into a case.

bynk.observe.trace_outside_test

[bynk.observe.trace_outside_test] Error: `trace` is only valid inside a `case` body

Cause: trace(Cap.op) appears outside a case. trace is a test-only builtin; elsewhere it is an ordinary identifier.

Fix: use trace(Cap.op) only inside a case. In production code, trace names whatever value you bind it to.

A call count that is not a literal

A call count is once or a literal <n> times (e.g. called 3 times); anything else — a variable, an expression, a negative number — does not parse as a count.