The trap I hit twice today — a file-wide DoesNotContain matching the doc
comment that explains the ban — was possible because three tests each
hand-rolled their own File.ReadAllText + path-walker, two of them mine. Fixed
at the root rather than per-test: SourceAssert now owns path walking and
literal extraction, with Literal(memberName, params parts) and Scopes() that
assert on the parsed VALUE. Tests that genuinely assert structure (the #if
DEBUG arm in InstanceIsolationTests, the absence of a whole API in the
locator) still read the file themselves, because those claims cannot be
reduced to a value — the helper is for literal facts only.
Shipping the fix introduced two defects, both caught by the build: a method
named Path shadowed System.IO.Path and broke the error message that names the
missing file, and Literal(fileName, memberName) invited a call that silently
resolved to a nonexistent path. Argument order is now required-context-first
so a wrong path is visible at the call site.
Suite 380/380, 0 warnings. LayerReorderPersistenceTests.RealMouseDrag flaked
once mid-session with no ytLive instance running and passed in isolation and
on re-run — the environment flake already recorded in HANDOFF.md, not a
regression from this change.
