t27c test-report exits 0 when tests fail #6668

Found while writing specs/automation/claim-guard-bar.t27 (PR #6662) in the overnight improvement loop the owner asked for on 2026-10-06.

t27c test-report --verbose printed FAIL rows for four deliberately false tests (1 > 2, a wrong digest accepted, a false string equality, a bar check at 89% recall) and still exited with code 0. Any gate that trusts the exit code passes a spec whose tests fail; only the printed table tells the truth.

Expected: a non-zero exit when at least one test fails. If the current behaviour is relied on, put it behind a flag such as --no-fail.

Acceptance: a fixture spec with one false test block makes the command exit non-zero. A mutant that restores exit 0 makes that check fail.

Boundary

• specs/automation/claim-guard-bar.t27

User Scenarios

• Given a .t27 spec containing a test block with a false assertion (e.g., 1 > 2), when running t27c test-report on that spec, then the command exits with a non-zero code.
• Given a .t27 spec where all test blocks pass, when running t27c test-report, then the command exits with code 0.
• Given a .t27 spec with multiple test blocks where at least one fails, when running t27c test-report --verbose, then the printed table shows FAIL rows and the process exits non-zero.

Requirements

• FR-001: t27c test-report MUST exit with a non-zero code when any test in the spec fails.
• FR-002: t27c test-report MUST exit with code 0 only when all tests in the spec pass.
• FR-003: If existing tooling relies on the current always-zero exit, the legacy behaviour MUST be opt-in via a flag such as --no-fail.

Success Criteria

• t27c test-report specs/automation/claim-guard-bar.t27 exits non-zero (the spec contains deliberate false tests).
• A new fixture spec specs/tools/tri/test.t27 with a single false test block makes t27c test-report specs/tools/tri/test.t27 exit non-zero.
• t27c test-report specs/tools/trinity/tri/test.t27 exits 0 (all tests pass in that spec).
• Mutating the compiler to restore exit 0 on failure causes the fixture check to fail (detected by the test suite).