diff --git a/test/byteid/libbyteid_test.ww b/test/byteid/libbyteid_test.ww
index b4c119b6..6ca92636 100644
--- a/test/byteid/libbyteid_test.ww
+++ b/test/byteid/libbyteid_test.ww
@@ -29,10 +29,9 @@ package libbyteid_test;
 //              graduation pinned the same way.
 //
 // Fixtureless modules are covered by import-probe stubs: `import`
-// drags the whole module into its own sep package. The driver silently
-// skips an unresolvable import, so each probe carries a sentinel that
-// must appear in a per-package .unit.ww, and the completeness scan
-// fails loudly on any lib/ dir not enrolled here.
+// drags the whole directory module into its own sep package. Each probe
+// carries a sentinel that must appear in a per-package .unit.ww, and
+// the completeness scan fails loudly on any lib/ dir not enrolled here.
 
 import os;
 import os.exec;
@@ -105,18 +104,18 @@ fn corpus() []ent = {
 	append(es, fx("lib/bytes/tokenize_test.ww"));
 	append(es, fx("lib/bytes/trim_test.ww"));
 	append(es, fx("lib/dirs/dirs_test.ww"));
-	append(es, fx("lib/encoding/base32/base32_test.ww"));
+	append(es, fxi("lib/encoding/base32/base32_test.ww", "lib/encoding"));
 	append(es, fx("lib/encoding/hex/hex_test.ww"));
 	append(es, fx("lib/encoding/utf8/rune_test.ww"));
 	append(es, fx("lib/encoding/utf8/encode_test.ww"));
 	append(es, fx("lib/encoding/utf8/decode_test.ww"));
 	append(es, fx("lib/encoding/utf8/types_test.ww"));
 	append(es, fx("lib/getopt/getopt_test.ww"));
-	append(es, fx("lib/hash/adler32/adler32_test.ww"));
-	append(es, fx("lib/hash/crc16/crc16_test.ww"));
-	append(es, fx("lib/hash/crc32/crc32_test.ww"));
-	append(es, fx("lib/hash/crc64/crc64_test.ww"));
-	append(es, fx("lib/hash/siphash/siphash_test.ww"));
+	append(es, fxi("lib/hash/adler32/adler32_test.ww", "lib/hash"));
+	append(es, fxi("lib/hash/crc16/crc16_test.ww", "lib/hash"));
+	append(es, fxi("lib/hash/crc32/crc32_test.ww", "lib/hash"));
+	append(es, fxi("lib/hash/crc64/crc64_test.ww", "lib/hash"));
+	append(es, fxi("lib/hash/siphash/siphash_test.ww", "lib/hash"));
 	append(es, fx("lib/math/checked/checked_test.ww"));
 	append(es, fx("lib/math/random/random_test.ww"));
 	append(es, fx("lib/memio/memio_test.ww"));
@@ -147,11 +146,12 @@ fn corpus() []ent = {
 		"package net;", "lib/net"));
 	append(es, pr("package main;\nimport hash;\nfn main() i32 = { return 0; };\n",
 		"package hash;", "lib/hash"));
-	// fnv lives off the driver's default root (lib/hash/fnv)
+	// fnv lives below the driver's default root, so its canonical
+	// directory is found from the explicit parent import root.
 	append(es, pri("package main;\nimport fnv;\nfn main() i32 = { return 0; };\n",
-		"lib/hash/fnv", "package fnv;", "lib/hash/fnv"));
-	// sentinel is a fn, not `package math;` — lib/math is also package
-	// math, so a silent fallback there would still match
+		"lib/hash", "package fnv;", "lib/hash/fnv"));
+	// Sentinel is a fn, not `package math;` — lib/math is also package
+	// math, so the package clause alone would not prove the right body.
 	append(es, pr("package main;\nimport crypto.math;\nfn main() i32 = { return 0; };\n",
 		"fn rotl32", "lib/crypto/math"));
 	append(es, pr("package main;\nimport c.libc;\nfn main() i32 = { return 0; };\n",
@@ -162,7 +162,7 @@ fn corpus() []ent = {
 	// sentinel: there is no dep unit to prove.
 	append(es, pr("package main;\nfn main() i32 = { return 0; };\n", "", ""));
 	append(es, fx("lib/ascii/ascii_test.ww"));
-	append(es, fx("lib/encoding/base64/base64_test.ww"));
+	append(es, fxi("lib/encoding/base64/base64_test.ww", "lib/encoding"));
 	append(es, fx("lib/errors/errno_test.ww"));
 	append(es, fx("lib/log/funcs_test.ww"));
 	append(es, fx("lib/log/global_test.ww"));
@@ -303,15 +303,11 @@ fn checkone(e: *ent) void = {
 		testenv.writefile(strings.concat(td, "/", base), body);
 	}; };
 
-	// dirname(fixture) leads the search path so bare same-module
-	// imports resolve as they do under the in-tree driver run.
+	// Most packages resolve from the driver's canonical lib/ root.
+	// Nested packages whose tests use a bare leaf import carry an
+	// explicit parent root in `inc`; pointing at the package directory
+	// itself would depend on the retired <import>.ww fallback.
 	let incs: []str = [];
-	if (e.fixture.len != 0) {
-		append(incs, strings.concat(testenv.repo(), "/",
-			dirnameof(e.fixture)));
-	} else { if (e.probe.len == 0 && e.moddir.len != 0) {
-		append(incs, strings.concat(testenv.repo(), "/", e.moddir));
-	}; };
 	if (e.inc.len != 0) {
 		append(incs, strings.concat(testenv.repo(), "/", e.inc));
 	};
@@ -338,10 +334,9 @@ fn checkone(e: *ent) void = {
 		fail(label, "cstage produced no resolved unit");
 	};
 
-	// probe coverage: the driver SILENTLY SKIPS an unresolvable
-	// import, shrinking the probe to an empty main that byte-ids
-	// trivially. The sentinel must appear in some per-package
-	// .unit.ww to prove the module landed.
+	// Probe coverage: resolution failures are loud, and the sentinel
+	// additionally proves that the expected directory body (rather
+	// than an accidental same-name package) landed.
 	if (e.sentinel.len != 0) {
 		let sepc: str = strings.concat(stemc, ".sepwork");
 		let names: []str = testenv.listdir(sepc);