expectOk<T> function
Plain-throw assertion helpers (dependency-light: AssertionError is
dart:core, no test/matcher import). Consumers get the same
unwrap-or-fail ergonomics in every test without per-test boilerplate.
Assert result is Ok and return its value; throws otherwise.
Implementation
/// Assert [result] is [Ok] and return its value; throws otherwise.
T expectOk<T>(Result<T> result, {String? because}) => switch (result) {
Ok<T>(:final value) => value,
Err<T>(:final problem) => throw AssertionError(
'expected Ok but got Err(${problem.type}, ${problem.status})'
'${because == null ? '' : ' — $because'}',
),
};