fix(test): make cached verification fixtures independent of old checkouts

crates/rds-core/tests/layering.rs

@@ -23,8 +23,10 @@ const FORBIDDEN_DEPS: &[&str] = &[
 
 #[test]
 fn rds_core_manifest_has_no_runtime_or_backend_dependencies() {
-    let manifest = std::fs::read_to_string(concat!(env!("CARGO_MANIFEST_DIR"), "/Cargo.toml"))
-        .expect("Cargo.toml readable");
+    // Cargo may reuse this test artifact after an isolated source checkout
+    // has been removed. Embed the manifest being compiled, rather than a
+    // runtime dependency on that checkout's absolute path.
+    let manifest = include_str!("../Cargo.toml");
 
     let deps = manifest
         .split("[dependencies]")

crates/rds-observe/tests/pipeline.rs

@@ -9,7 +9,7 @@ mod admin;
 
 use std::fs;
 use std::io::Write as _;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::process::{Command, Output};
 use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 
@@ -56,7 +56,14 @@ impl Stack {
             .unwrap();
         Self {
             root,
-            config: Path::new(env!("CARGO_MANIFEST_DIR")).join("../../ops/observability"),
+            // This fixture reads current on-disk Compose files. Resolve the
+            // checkout Cargo is running now, not a deleted compilation path
+            // retained in a shared target directory.
+            config: PathBuf::from(
+                std::env::var_os("CARGO_MANIFEST_DIR")
+                    .expect("run the infrastructure fixture through cargo test"),
+            )
+            .join("../../ops/observability"),
             project: format!("rds-observe-{suffix}"),
             password,
         }

docs/continuation-plan.md

@@ -31,6 +31,7 @@ older revisions independently; neither is silently assumed to equal main.
 | S5 | Input ACK, payload receipt, decoded-frame submission and physical pixels prove different things. | Native diagnostics, visual probe, bench reports | Exact-build typing/Backspace count and causal submission evidence; loss and unanswered probes included |
 | S6 | Optional platform/media modules remain real stubs. Directory sync, native serving on macOS/Wayland, audio and automatic GDS grant issuance are not implemented. | Backend probe files, audio crate, sync engine, GDS policy adapters | Explicit later implementation/qualification tasks; never mark these complete from X11 or loopback results |
 | S7 | Owned relay drain priority was reused as RTT, making progress budgets effectively infinite. | Noq path policy | Keep real RTT separate from ranking; negative deadline regression and positive engine/drain qualification |
+| S8 | A compiled architecture test retained an absolute source-checkout filename, making shared-cache verification depend on a removed checkout. | Core layering test; infrastructure fixture path resolution | Embed source-only assertions; resolve required live fixture files from the runtime checkout; preserve the original assertions |
 
 ## Wave A — interactive recovery correctness (W3.6, W6.8)
 
@@ -98,6 +99,10 @@ both peers, with truthful measured recovery and no unrequested process restart.
 5. Confirm main OID, consumed gitlink, installed artifact digest, running process
    identity and effective endpoint/policy config independently on each device.
    A clean checkout alone is not complete synchronization.
+6. Verify reusable test artifacts independently of an old temporary checkout.
+   Embedded fixture data belongs to the compiled source; external fixture files
+   must resolve the actual running checkout. Serialize qualification processes
+   that share one Cargo target directory, including their test/doctest phases.
 
 Exit: published implementation, estate consumption, runtime receipts and current
 documentation agree; any remaining mismatch has its owning task and verifier.

docs/reports/rds-relocatable-verification-20261007.md

@@ -0,0 +1,27 @@
+# Verification fixtures across isolated checkouts — 2026-10-07
+
+The core layering test embedded `CARGO_MANIFEST_DIR` as an absolute runtime
+filename. Reusing its compiled artifact after that checkout was removed failed
+with `Cargo.toml readable: NotFound`; this did not establish an invalid core
+dependency graph. The failing verification is retained separately.
+
+Embed the tested manifest with `include_str!("../Cargo.toml")`. The dependency
+assertions remain mandatory, and the compiler tracks the included input. The
+existing test passes after the correction. Its actual compiled artifact also
+passes when invoked from an empty directory with a nonexistent runtime
+`CARGO_MANIFEST_DIR`, without reading a source checkout.
+
+The explicit Linux observability infrastructure fixture needs live Compose
+files instead. Resolve Cargo's runtime manifest directory there, rather than
+a removed compilation path. This changes fixture location handling; it does
+not claim a new Docker/pipeline qualification. Full platform CI remains the
+broader verifier.
+
+This is a verification-lifecycle correction with no transport or wire change.
+The [standby measurements](bench-standby-20261007.md) remain scoped transport
+evidence; they do not measure this fixture behavior or close a product gate.
+[Rust's `include_str!` documentation](https://doc.rust-lang.org/std/macro.include_str.html)
+defines compile-time file inclusion relative to the source file. Cargo's
+[environment contract](https://doc.rust-lang.org/cargo/reference/environment-variables.html)
+distinguishes values expanded during compilation from the running test's
+environment. Both mechanisms predate the requested research boundary.