Adds test/terminal/buffer/range_test.dart — 38 unit tests covering
the small pure-Dart files in lib/src/terminal/src/core/buffer/:
- cell_offset.dart 23 / 23 (was 0 / 23)
- range.dart 13 / 13 (was 0 / 13)
- segment.dart 13 / 13 (was 0 / 13)
- range_line.dart 30 / 30 (was 0 / 30)
- range_block.dart 48 / 48 (was 0 / 48)
Total project line coverage 34.90% → 36.39%; coverage_floor in
pubspec.yaml bumped 34 → 36 in lockstep.
Tests exercise the abstract BufferRange operator==/hashCode/toString
via a local _StubRange (BufferRangeLine and BufferRangeBlock both
override those, so the base versions are otherwise unreachable —
worth a stub rather than carving the lines out of coverage). The
denormalized-input branches in Block contain/toSegments/extend get
explicit cases too.
Pure Dart, no Flutter dependency — uses package:test/test.dart and
runs in <100ms.
First batch under T-91; line.dart and buffer.dart land in subsequent
commits with their own floor bumps.
Co-Authored-By: Claude <noreply@anthropic.com>