diff --git a/Makefile b/Makefile
index fa5f2a96..3d15566b 100644
--- a/Makefile
+++ b/Makefile
@@ -488,7 +488,9 @@ LIBRARY_TESTS = lib/errors/errno_test.ww lib/ascii/ascii_test.ww \
 	  lib/strconv/test/int_test.ww lib/strings/strings_test.ww \
 	  lib/strings/suffix_test.ww lib/strings/contains_test.ww \
 	  lib/strings/index_test.ww lib/strings/compare_test.ww \
-	  lib/bytes/bytes_test.ww lib/encoding/utf8/utf8_test.ww \
+	  lib/bytes/equal_test.ww lib/bytes/index_test.ww \
+	  lib/bytes/contains_test.ww lib/bytes/tokenize_test.ww \
+	  lib/bytes/trim_test.ww lib/encoding/utf8/utf8_test.ww \
 	  lib/bufio/bufio_test.ww lib/math/random/random_test.ww \
 	  lib/math/checked/checked_test.ww lib/fmt/fmt_test.ww \
 	  lib/log/log_test.ww lib/log/silent_test.ww lib/fnmatch/fnmatch_test.ww \
diff --git a/lib/bytes/contains_test.ww b/lib/bytes/contains_test.ww
new file mode 100644
index 00000000..66d40e2b
--- /dev/null
+++ b/lib/bytes/contains_test.ww
@@ -0,0 +1,59 @@
+// containstest — exercises bytes.contains/hasprefix/hassuffix. A
+// failing row aborts via the assert/abort builtin (task #5 @test
+// conversion). Vectors mirror ref/hare/bytes/contains.ha.
+
+package bytes_test;
+
+import bytes;
+
+@test fn contains_cases() void = {
+	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
+	assert(!(!bytes.contains(a[0:4], 7u8)));
+	assert(!( bytes.contains(a[0:4], 42u8)));
+	let n: [2]u8; n[0] = 3u8; n[1] = 3u8;
+	assert(!(!bytes.contains(a[0:4], n[0:2])));
+	let m: [2]u8; m[0] = 9u8; m[1] = 9u8;
+	assert(!( bytes.contains(a[0:4], m[0:2])));
+
+	// Variadic rows. ref/hare/bytes/contains.ha:6.
+	assert(!( bytes.contains(a[0:4])));
+	assert(!(!bytes.contains(a[0:4], n[0:2])));
+	assert(!(!bytes.contains(a[0:4], 7u8)));
+	assert(!(!bytes.contains(a[0:4], m[0:2], n[0:2], 42u8)));
+	assert(!( bytes.contains(a[0:4], m[0:2], 42u8, m[0:2])));
+};
+
+// ref/hare/bytes/contains.ha:25.
+
+@test fn hasprefix_cases() void = {
+	let z: [1]u8;
+	assert(!(!bytes.hasprefix(z[0:0], z[0:0])));
+	let one: [1]u8; one[0] = 0u8;
+	assert(!(!bytes.hasprefix(one[0:1], z[0:0])));
+	assert(!( bytes.hasprefix(z[0:0], one[0:1])));
+	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
+	let p12: [2]u8; p12[0] = 1u8; p12[1] = 2u8;
+	assert(!(!bytes.hasprefix(a[0:3], p12[0:2])));
+	let p11: [2]u8; p11[0] = 1u8; p11[1] = 1u8;
+	assert(!( bytes.hasprefix(a[0:3], p11[0:2])));
+	let pl: [4]u8; pl[0] = 1u8; pl[1] = 2u8; pl[2] = 3u8; pl[3] = 4u8;
+	assert(!( bytes.hasprefix(a[0:3], pl[0:4])));
+};
+
+// ref/hare/bytes/contains.ha:40.
+
+@test fn hassuffix_cases() void = {
+	let z: [1]u8;
+	assert(!(!bytes.hassuffix(z[0:0], z[0:0])));
+	let one: [1]u8; one[0] = 0u8;
+	assert(!(!bytes.hassuffix(one[0:1], z[0:0])));
+	assert(!( bytes.hassuffix(z[0:0], one[0:1])));
+	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
+	let s23: [2]u8; s23[0] = 2u8; s23[1] = 3u8;
+	assert(!(!bytes.hassuffix(a[0:3], s23[0:2])));
+	let s22: [2]u8; s22[0] = 2u8; s22[1] = 2u8;
+	assert(!( bytes.hassuffix(a[0:3], s22[0:2])));
+	let a4: [4]u8; a4[0] = 1u8; a4[1] = 2u8; a4[2] = 3u8; a4[3] = 4u8;
+	let s234: [3]u8; s234[0] = 2u8; s234[1] = 3u8; s234[2] = 4u8;
+	assert(!(!bytes.hassuffix(a4[0:4], s234[0:3])));
+};
diff --git a/lib/bytes/equal_test.ww b/lib/bytes/equal_test.ww
new file mode 100644
index 00000000..13591a5e
--- /dev/null
+++ b/lib/bytes/equal_test.ww
@@ -0,0 +1,23 @@
+// equaltest — exercises bytes.equal. A failing row aborts via the
+// assert/abort builtin (task #5 @test conversion).
+// Vectors mirror ref/hare/bytes/equal.ha.
+
+package bytes_test;
+
+import bytes;
+
+// ref/hare/bytes/equal.ha:21.
+
+@test fn equal_cases() void = {
+	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
+	let b: [3]u8; b[0] = 1u8; b[1] = 2u8; b[2] = 3u8;
+	let c: [3]u8; c[0] = 1u8; c[1] = 4u8; c[2] = 5u8;
+	let d: [4]u8; d[0] = 1u8; d[1] = 2u8; d[2] = 3u8; d[3] = 4u8;
+	let e: [2]u8; e[0] = 1u8; e[1] = 2u8;
+	let z: [1]u8;
+	assert(!(!bytes.equal(a[0:3], b[0:3])));
+	assert(!( bytes.equal(a[0:3], c[0:3])));
+	assert(!( bytes.equal(a[0:3], d[0:4])));
+	assert(!( bytes.equal(a[0:3], e[0:2])));
+	assert(!(!bytes.equal(z[0:0], z[0:0])));	// empty-empty
+};
diff --git a/lib/bytes/index_test.ww b/lib/bytes/index_test.ww
new file mode 100644
index 00000000..a8992863
--- /dev/null
+++ b/lib/bytes/index_test.ww
@@ -0,0 +1,157 @@
+// indextest — exercises bytes.index/rindex, u8 and []u8 arms. A
+// failing row aborts via the assert/abort builtin (task #5 @test
+// conversion). Vectors mirror ref/hare/bytes/index.ha.
+
+package bytes_test;
+
+import bytes;
+
+// ref/hare/bytes/index.ha:112.
+
+@test fn index_byte_cases() void = {
+	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
+	match (bytes.index(a[0:4], 1u8)) {
+	case let i: i32 => { assert(!(i != 0)); };
+	case void => abort();
+	};
+	match (bytes.index(a[0:4], 3u8)) {
+	case let i: i32 => { assert(!(i != 1)); };
+	case void => abort();
+	};
+	match (bytes.index(a[0:4], 7u8)) {
+	case let i: i32 => { assert(!(i != 3)); };
+	case void => abort();
+	};
+	match (bytes.index(a[0:4], 42u8)) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+	let z: [1]u8;
+	match (bytes.index(z[0:0], 42u8)) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+};
+
+// ref/hare/bytes/index.ha:128-139. Vector strings copied verbatim where
+// representable as ASCII byte sequences.
+
+@test fn index_slice_cases() void = {
+	let h1: [4]u8; h1[0] = 1u8; h1[1] = 42u8; h1[2] = 24u8; h1[3] = 0u8;
+	let n1: [2]u8; n1[0] = 42u8; n1[1] = 24u8;
+	match (bytes.index(h1[0:3], n1[0:2])) {
+	case let i: i32 => { assert(!(i != 1)); };
+	case void => abort();
+	};
+
+	let h2: [4]u8; h2[0] = 1u8; h2[1] = 3u8; h2[2] = 3u8; h2[3] = 7u8;
+	let n2: [2]u8; n2[0] = 3u8; n2[1] = 3u8;
+	match (bytes.index(h2[0:4], n2[0:2])) {
+	case let i: i32 => { assert(!(i != 1)); };
+	case void => abort();
+	};
+
+	// needle longer than haystack — void
+	let h3: [3]u8; h3[0] = 1u8; h3[1] = 2u8; h3[2] = 3u8;
+	let n3: [4]u8; n3[0] = 1u8; n3[1] = 2u8; n3[2] = 3u8; n3[3] = 4u8;
+	match (bytes.index(h3[0:3], n3[0:4])) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+
+	// len(haystack) == len(needle), match — offset 0
+	let h4: [2]u8; h4[0] = 42u8; h4[1] = 20u8;
+	let n4: [2]u8; n4[0] = 42u8; n4[1] = 20u8;
+	match (bytes.index(h4[0:2], n4[0:2])) {
+	case let i: i32 => { assert(!(i != 0)); };
+	case void => abort();
+	};
+
+	// len(haystack) == len(needle), no match — void
+	let h5: [4]u8; h5[0] = 1u8; h5[1] = 1u8; h5[2] = 1u8; h5[3] = 2u8;
+	let n5: [4]u8; n5[0] = 1u8; n5[1] = 1u8; n5[2] = 1u8; n5[3] = 3u8;
+	match (bytes.index(h5[0:4], n5[0:4])) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+
+	// Partial-prefix recovery — needle [1,1,2] aligns at i=1 after the
+	// false-start at i=0 ([1,1,1] mismatches at byte 2). Pins the
+	// naive scanner's restart discipline.
+	let h6: [4]u8; h6[0] = 1u8; h6[1] = 1u8; h6[2] = 1u8; h6[3] = 2u8;
+	let n6s: [3]u8; n6s[0] = 1u8; n6s[1] = 1u8; n6s[2] = 2u8;
+	match (bytes.index(h6[0:4], n6s[0:3])) {
+	case let i: i32 => { assert(!(i != 1)); };
+	case void => abort();
+	};
+
+	// Same shape, longer haystack with no match anywhere.
+	let h7: [5]u8; h7[0] = 1u8; h7[1] = 1u8; h7[2] = 1u8; h7[3] = 3u8; h7[4] = 2u8;
+	let n7: [4]u8; n7[0] = 1u8; n7[1] = 1u8; n7[2] = 1u8; n7[3] = 2u8;
+	match (bytes.index(h7[0:5], n7[0:4])) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+
+	// empty needle — Hare returns 0 (ref/hare/bytes/index.ha:63).
+	let z: [1]u8;
+	let zn: [1]u8;
+	match (bytes.index(h2[0:4], zn[0:0])) {
+	case let i: i32 => { assert(!(i != 0)); };
+	case void => abort();
+	};
+	// empty haystack, non-empty needle — void
+	match (bytes.index(z[0:0], n3[0:3])) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+
+	// single-byte slice needle — should semantically equal u8 arm
+	let n6: [1]u8; n6[0] = 7u8;
+	match (bytes.index(h2[0:4], n6[0:1])) {
+	case let i: i32 => { assert(!(i != 3)); };
+	case void => abort();
+	};
+};
+
+// ref/hare/bytes/index.ha:118.
+
+@test fn rindex_byte_cases() void = {
+	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
+	match (bytes.rindex(a[0:4], 3u8)) {
+	case let i: i32 => { assert(!(i != 2)); };
+	case void => abort();
+	};
+	match (bytes.rindex(a[0:4], 42u8)) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+	let z: [1]u8;
+	match (bytes.rindex(z[0:0], 42u8)) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+};
+
+// ref/hare/bytes/index.ha:123-125. Distinguishes from index when the
+// needle appears more than once.
+
+@test fn rindex_slice_cases() void = {
+	let a: [4]u8; a[0] = 1u8; a[1] = 1u8; a[2] = 1u8; a[3] = 2u8;
+	let n11: [2]u8; n11[0] = 1u8; n11[1] = 1u8;
+	match (bytes.rindex(a[0:4], n11[0:2])) {
+	case let i: i32 => { assert(!(i != 1)); };
+	case void => abort();
+	};
+	let n12: [2]u8; n12[0] = 1u8; n12[1] = 2u8;
+	match (bytes.rindex(a[0:4], n12[0:2])) {
+	case let i: i32 => { assert(!(i != 2)); };
+	case void => abort();
+	};
+	// absent
+	let n99: [2]u8; n99[0] = 9u8; n99[1] = 9u8;
+	match (bytes.rindex(a[0:4], n99[0:2])) {
+	case let i: i32 => abort();
+	case void => void;
+	};
+};
diff --git a/lib/bytes/bytes_test.ww b/lib/bytes/tokenize_test.ww
similarity index 61%
rename from lib/bytes/bytes_test.ww
rename to lib/bytes/tokenize_test.ww
index 89f43eaa..4c289725 100644
--- a/lib/bytes/bytes_test.ww
+++ b/lib/bytes/tokenize_test.ww
@@ -1,243 +1,12 @@
-// bytestest — exercises lib/bytes. Run with
-// `out/bin/ww run lib/bytes/bytestest.ww`. A failing row aborts via the
-// assert/abort builtin (task #5 @test conversion).
-//
-// Vectors mirror Hare's @test fns in ref/hare/bytes/equal.ha,
-// ref/hare/bytes/index.ha, ref/hare/bytes/contains.ha.
+// tokenizetest — exercises the bytes tokenize/splitn/cut families.
+// A failing row aborts via the assert/abort builtin (task #5 @test
+// conversion). Vectors mirror ref/hare/bytes/tokenize.ha.
 
 package bytes_test;
 
 import bytes;
 import os;
 
-// ---- equal ------------------------------------------------------------
-// ref/hare/bytes/equal.ha:21.
-
-@test fn equal_cases() void = {
-	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
-	let b: [3]u8; b[0] = 1u8; b[1] = 2u8; b[2] = 3u8;
-	let c: [3]u8; c[0] = 1u8; c[1] = 4u8; c[2] = 5u8;
-	let d: [4]u8; d[0] = 1u8; d[1] = 2u8; d[2] = 3u8; d[3] = 4u8;
-	let e: [2]u8; e[0] = 1u8; e[1] = 2u8;
-	let z: [1]u8;
-	assert(!(!bytes.equal(a[0:3], b[0:3])));
-	assert(!( bytes.equal(a[0:3], c[0:3])));
-	assert(!( bytes.equal(a[0:3], d[0:4])));
-	assert(!( bytes.equal(a[0:3], e[0:2])));
-	assert(!(!bytes.equal(z[0:0], z[0:0])));	// empty-empty
-};
-
-// ---- index(u8) --------------------------------------------------------
-// ref/hare/bytes/index.ha:112.
-
-@test fn index_byte_cases() void = {
-	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
-	match (bytes.index(a[0:4], 1u8)) {
-	case let i: i32 => { assert(!(i != 0)); };
-	case void => abort();
-	};
-	match (bytes.index(a[0:4], 3u8)) {
-	case let i: i32 => { assert(!(i != 1)); };
-	case void => abort();
-	};
-	match (bytes.index(a[0:4], 7u8)) {
-	case let i: i32 => { assert(!(i != 3)); };
-	case void => abort();
-	};
-	match (bytes.index(a[0:4], 42u8)) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-	let z: [1]u8;
-	match (bytes.index(z[0:0], 42u8)) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-};
-
-// ---- index([]u8) ------------------------------------------------------
-// ref/hare/bytes/index.ha:128-139. Vector strings copied verbatim where
-// representable as ASCII byte sequences.
-
-@test fn index_slice_cases() void = {
-	let h1: [4]u8; h1[0] = 1u8; h1[1] = 42u8; h1[2] = 24u8; h1[3] = 0u8;
-	let n1: [2]u8; n1[0] = 42u8; n1[1] = 24u8;
-	match (bytes.index(h1[0:3], n1[0:2])) {
-	case let i: i32 => { assert(!(i != 1)); };
-	case void => abort();
-	};
-
-	let h2: [4]u8; h2[0] = 1u8; h2[1] = 3u8; h2[2] = 3u8; h2[3] = 7u8;
-	let n2: [2]u8; n2[0] = 3u8; n2[1] = 3u8;
-	match (bytes.index(h2[0:4], n2[0:2])) {
-	case let i: i32 => { assert(!(i != 1)); };
-	case void => abort();
-	};
-
-	// needle longer than haystack — void
-	let h3: [3]u8; h3[0] = 1u8; h3[1] = 2u8; h3[2] = 3u8;
-	let n3: [4]u8; n3[0] = 1u8; n3[1] = 2u8; n3[2] = 3u8; n3[3] = 4u8;
-	match (bytes.index(h3[0:3], n3[0:4])) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-
-	// len(haystack) == len(needle), match — offset 0
-	let h4: [2]u8; h4[0] = 42u8; h4[1] = 20u8;
-	let n4: [2]u8; n4[0] = 42u8; n4[1] = 20u8;
-	match (bytes.index(h4[0:2], n4[0:2])) {
-	case let i: i32 => { assert(!(i != 0)); };
-	case void => abort();
-	};
-
-	// len(haystack) == len(needle), no match — void
-	let h5: [4]u8; h5[0] = 1u8; h5[1] = 1u8; h5[2] = 1u8; h5[3] = 2u8;
-	let n5: [4]u8; n5[0] = 1u8; n5[1] = 1u8; n5[2] = 1u8; n5[3] = 3u8;
-	match (bytes.index(h5[0:4], n5[0:4])) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-
-	// Partial-prefix recovery — needle [1,1,2] aligns at i=1 after the
-	// false-start at i=0 ([1,1,1] mismatches at byte 2). Pins the
-	// naive scanner's restart discipline.
-	let h6: [4]u8; h6[0] = 1u8; h6[1] = 1u8; h6[2] = 1u8; h6[3] = 2u8;
-	let n6s: [3]u8; n6s[0] = 1u8; n6s[1] = 1u8; n6s[2] = 2u8;
-	match (bytes.index(h6[0:4], n6s[0:3])) {
-	case let i: i32 => { assert(!(i != 1)); };
-	case void => abort();
-	};
-
-	// Same shape, longer haystack with no match anywhere.
-	let h7: [5]u8; h7[0] = 1u8; h7[1] = 1u8; h7[2] = 1u8; h7[3] = 3u8; h7[4] = 2u8;
-	let n7: [4]u8; n7[0] = 1u8; n7[1] = 1u8; n7[2] = 1u8; n7[3] = 2u8;
-	match (bytes.index(h7[0:5], n7[0:4])) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-
-	// empty needle — Hare returns 0 (ref/hare/bytes/index.ha:63).
-	let z: [1]u8;
-	let zn: [1]u8;
-	match (bytes.index(h2[0:4], zn[0:0])) {
-	case let i: i32 => { assert(!(i != 0)); };
-	case void => abort();
-	};
-	// empty haystack, non-empty needle — void
-	match (bytes.index(z[0:0], n3[0:3])) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-
-	// single-byte slice needle — should semantically equal u8 arm
-	let n6: [1]u8; n6[0] = 7u8;
-	match (bytes.index(h2[0:4], n6[0:1])) {
-	case let i: i32 => { assert(!(i != 3)); };
-	case void => abort();
-	};
-};
-
-// ---- rindex(u8) -------------------------------------------------------
-// ref/hare/bytes/index.ha:118.
-
-@test fn rindex_byte_cases() void = {
-	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
-	match (bytes.rindex(a[0:4], 3u8)) {
-	case let i: i32 => { assert(!(i != 2)); };
-	case void => abort();
-	};
-	match (bytes.rindex(a[0:4], 42u8)) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-	let z: [1]u8;
-	match (bytes.rindex(z[0:0], 42u8)) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-};
-
-// ---- rindex([]u8) -----------------------------------------------------
-// ref/hare/bytes/index.ha:123-125. Distinguishes from index when the
-// needle appears more than once.
-
-@test fn rindex_slice_cases() void = {
-	let a: [4]u8; a[0] = 1u8; a[1] = 1u8; a[2] = 1u8; a[3] = 2u8;
-	let n11: [2]u8; n11[0] = 1u8; n11[1] = 1u8;
-	match (bytes.rindex(a[0:4], n11[0:2])) {
-	case let i: i32 => { assert(!(i != 1)); };
-	case void => abort();
-	};
-	let n12: [2]u8; n12[0] = 1u8; n12[1] = 2u8;
-	match (bytes.rindex(a[0:4], n12[0:2])) {
-	case let i: i32 => { assert(!(i != 2)); };
-	case void => abort();
-	};
-	// absent
-	let n99: [2]u8; n99[0] = 9u8; n99[1] = 9u8;
-	match (bytes.rindex(a[0:4], n99[0:2])) {
-	case let i: i32 => abort();
-	case void => void;
-	};
-};
-
-// ---- contains ---------------------------------------------------------
-
-@test fn contains_cases() void = {
-	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
-	assert(!(!bytes.contains(a[0:4], 7u8)));
-	assert(!( bytes.contains(a[0:4], 42u8)));
-	let n: [2]u8; n[0] = 3u8; n[1] = 3u8;
-	assert(!(!bytes.contains(a[0:4], n[0:2])));
-	let m: [2]u8; m[0] = 9u8; m[1] = 9u8;
-	assert(!( bytes.contains(a[0:4], m[0:2])));
-
-	// Variadic rows. ref/hare/bytes/contains.ha:6.
-	assert(!( bytes.contains(a[0:4])));
-	assert(!(!bytes.contains(a[0:4], n[0:2])));
-	assert(!(!bytes.contains(a[0:4], 7u8)));
-	assert(!(!bytes.contains(a[0:4], m[0:2], n[0:2], 42u8)));
-	assert(!( bytes.contains(a[0:4], m[0:2], 42u8, m[0:2])));
-};
-
-// ---- hasprefix --------------------------------------------------------
-// ref/hare/bytes/contains.ha:25.
-
-@test fn hasprefix_cases() void = {
-	let z: [1]u8;
-	assert(!(!bytes.hasprefix(z[0:0], z[0:0])));
-	let one: [1]u8; one[0] = 0u8;
-	assert(!(!bytes.hasprefix(one[0:1], z[0:0])));
-	assert(!( bytes.hasprefix(z[0:0], one[0:1])));
-	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
-	let p12: [2]u8; p12[0] = 1u8; p12[1] = 2u8;
-	assert(!(!bytes.hasprefix(a[0:3], p12[0:2])));
-	let p11: [2]u8; p11[0] = 1u8; p11[1] = 1u8;
-	assert(!( bytes.hasprefix(a[0:3], p11[0:2])));
-	let pl: [4]u8; pl[0] = 1u8; pl[1] = 2u8; pl[2] = 3u8; pl[3] = 4u8;
-	assert(!( bytes.hasprefix(a[0:3], pl[0:4])));
-};
-
-// ---- hassuffix --------------------------------------------------------
-// ref/hare/bytes/contains.ha:40.
-
-@test fn hassuffix_cases() void = {
-	let z: [1]u8;
-	assert(!(!bytes.hassuffix(z[0:0], z[0:0])));
-	let one: [1]u8; one[0] = 0u8;
-	assert(!(!bytes.hassuffix(one[0:1], z[0:0])));
-	assert(!( bytes.hassuffix(z[0:0], one[0:1])));
-	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
-	let s23: [2]u8; s23[0] = 2u8; s23[1] = 3u8;
-	assert(!(!bytes.hassuffix(a[0:3], s23[0:2])));
-	let s22: [2]u8; s22[0] = 2u8; s22[1] = 2u8;
-	assert(!( bytes.hassuffix(a[0:3], s22[0:2])));
-	let a4: [4]u8; a4[0] = 1u8; a4[1] = 2u8; a4[2] = 3u8; a4[3] = 4u8;
-	let s234: [3]u8; s234[0] = 2u8; s234[1] = 3u8; s234[2] = 4u8;
-	assert(!(!bytes.hassuffix(a4[0:4], s234[0:3])));
-};
-
-// ---- tokenize / rtokenize / peektoken / remainingtokens -----------
 // ref/hare/bytes/tokenize.ha:258. Hare's @test fn tokenize / rtokenize
 // drives the iterator through an expected-token sequence and asserts
 // `equal(p, n)` (peek == next), `equal(n, want)` (next == expected).
@@ -441,96 +210,6 @@ fn expect_done(t: *bytes.tokenizer) void = {
 	assert(!(!bytes.equal(r2, e_12[0:2])));
 };
 
-// ---- ltrim / rtrim / trim ---------------------------------------------
-// ref/hare/bytes/trim.ha:29 — Hare's @test fn trim pins
-// `trim([0,1,2,3,5,0], 0) == [1,2,3,5]`, `trim([0,0,0], 0) == []`,
-// `trim([], 0) == []`. ww spreads the matrix across ltrim/rtrim/trim.
-
-fn beq(got: []u8, want: []u8) bool = {
-	if (got.len != want.len) { return false; };
-	let i: i32 = 0;
-	for (i < got.len) {
-		if (got[i] != want[i]) { return false; };
-		i += 1;
-	};
-	return true;
-};
-
-@test fn ltrim_cases() void = {
-	let z: [1]u8;
-
-	// [0,0,1,2] / 0 -> [1,2]
-	let a: [4]u8; a[0] = 0u8; a[1] = 0u8; a[2] = 1u8; a[3] = 2u8;
-	let ea: [2]u8; ea[0] = 1u8; ea[1] = 2u8;
-	assert(!(!beq(bytes.ltrim(a[0:4], 0u8), ea[0:2])));
-
-	// [1,2,3] / 0 -> [1,2,3] (no leading match)
-	let b: [3]u8; b[0] = 1u8; b[1] = 2u8; b[2] = 3u8;
-	assert(!(!beq(bytes.ltrim(b[0:3], 0u8), b[0:3])));
-
-	// [0,0,0] / 0 -> [] (full match) — the bare `let c: [3]u8;` zero-init
-	// row that surfaced #16 (a dirtied slot read non-zero, ltrim trimmed
-	// nothing). Now reads {0,0,0} and trims to empty.
-	let c: [3]u8;
-	assert(!(!beq(bytes.ltrim(c[0:3], 0u8), z[0:0])));
-
-	// [] / 0 -> [] (empty input)
-	assert(!(!beq(bytes.ltrim(z[0:0], 0u8), z[0:0])));
-};
-
-@test fn rtrim_cases() void = {
-	let z: [1]u8;
-
-	// [1,2,0,0] / 0 -> [1,2]
-	let a: [4]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 0u8; a[3] = 0u8;
-	let ea: [2]u8; ea[0] = 1u8; ea[1] = 2u8;
-	assert(!(!beq(bytes.rtrim(a[0:4], 0u8), ea[0:2])));
-
-	// [1,2,3] / 0 -> [1,2,3] (no trailing match)
-	let b: [3]u8; b[0] = 1u8; b[1] = 2u8; b[2] = 3u8;
-	assert(!(!beq(bytes.rtrim(b[0:3], 0u8), b[0:3])));
-
-	// [0,0,0] / 0 -> [] (full match)
-	let c: [3]u8;
-	assert(!(!beq(bytes.rtrim(c[0:3], 0u8), z[0:0])));
-
-	// [] / 0 -> [] (empty input)
-	assert(!(!beq(bytes.rtrim(z[0:0], 0u8), z[0:0])));
-};
-
-@test fn trim_cases() void = {
-	let z: [1]u8;
-
-	// [0,1,2,3,5,0] / 0 -> [1,2,3,5]
-	let a: [6]u8;
-	a[0] = 0u8; a[1] = 1u8; a[2] = 2u8;
-	a[3] = 3u8; a[4] = 5u8; a[5] = 0u8;
-	let ea: [4]u8; ea[0] = 1u8; ea[1] = 2u8; ea[2] = 3u8; ea[3] = 5u8;
-	assert(!(!beq(bytes.trim(a[0:6], 0u8), ea[0:4])));
-
-	// [0,5,0] / 5 -> [0,5,0] (only 5 in trim set; boundary mismatch)
-	let b: [3]u8; b[0] = 0u8; b[1] = 5u8; b[2] = 0u8;
-	assert(!(!beq(bytes.trim(b[0:3], 5u8), b[0:3])));
-
-	// [0,1,42,1,0] / {0,42} -> [1,42,1] (multi-byte trim set)
-	let c: [5]u8;
-	c[0] = 0u8; c[1] = 1u8; c[2] = 42u8; c[3] = 1u8; c[4] = 0u8;
-	let ec: [3]u8; ec[0] = 1u8; ec[1] = 42u8; ec[2] = 1u8;
-	assert(!(!beq(bytes.trim(c[0:5], 0u8, 42u8), ec[0:3])));
-
-	// [0,0,0] / 0 -> [] (full match)
-	let d: [3]u8;
-	assert(!(!beq(bytes.trim(d[0:3], 0u8), z[0:0])));
-
-	// [] / 0 -> [] (empty input, Hare ref/hare/bytes/trim.ha:34)
-	assert(!(!beq(bytes.trim(z[0:0], 0u8), z[0:0])));
-
-	// [1,2,3,5] / 0 -> [1,2,3,5] (Hare ref/hare/bytes/trim.ha:31)
-	let e: [4]u8; e[0] = 1u8; e[1] = 2u8; e[2] = 3u8; e[3] = 5u8;
-	assert(!(!beq(bytes.trim(e[0:4], 0u8), e[0:4])));
-};
-
-// ---- splitn / rsplitn / split -----------------------------------------
 // ref/hare/bytes/tokenize.ha:330 (@test fn split). Hare's table mixes
 // strings; ww spells the vectors as byte arrays explicitly.
 //
@@ -697,7 +376,6 @@ fn expect_tok(toks: [][]u8, i: i32, want: []u8) void = {
 	os.free(t2.ptr: *void, (t2.cap: u64) * 24u64);
 };
 
-// ---- cut / rcut -------------------------------------------------------
 // ref/hare/bytes/tokenize.ha:429 (@test fn cut). Borrowed views; each
 // half asserted via equal(). Needle order is ww's (u8 | []u8). Rows use
 // the destructure form `let (before, after) = cut(...)` to drive the #10
diff --git a/lib/bytes/trim_test.ww b/lib/bytes/trim_test.ww
new file mode 100644
index 00000000..7e1a25cc
--- /dev/null
+++ b/lib/bytes/trim_test.ww
@@ -0,0 +1,95 @@
+// trimtest — exercises bytes.ltrim/rtrim/trim. A failing row aborts
+// via the assert/abort builtin (task #5 @test conversion).
+// Vectors mirror ref/hare/bytes/trim.ha.
+
+package bytes_test;
+
+import bytes;
+
+// ref/hare/bytes/trim.ha:29 — Hare's @test fn trim pins
+// `trim([0,1,2,3,5,0], 0) == [1,2,3,5]`, `trim([0,0,0], 0) == []`,
+// `trim([], 0) == []`. ww spreads the matrix across ltrim/rtrim/trim.
+
+fn beq(got: []u8, want: []u8) bool = {
+	if (got.len != want.len) { return false; };
+	let i: i32 = 0;
+	for (i < got.len) {
+		if (got[i] != want[i]) { return false; };
+		i += 1;
+	};
+	return true;
+};
+
+@test fn ltrim_cases() void = {
+	let z: [1]u8;
+
+	// [0,0,1,2] / 0 -> [1,2]
+	let a: [4]u8; a[0] = 0u8; a[1] = 0u8; a[2] = 1u8; a[3] = 2u8;
+	let ea: [2]u8; ea[0] = 1u8; ea[1] = 2u8;
+	assert(!(!beq(bytes.ltrim(a[0:4], 0u8), ea[0:2])));
+
+	// [1,2,3] / 0 -> [1,2,3] (no leading match)
+	let b: [3]u8; b[0] = 1u8; b[1] = 2u8; b[2] = 3u8;
+	assert(!(!beq(bytes.ltrim(b[0:3], 0u8), b[0:3])));
+
+	// [0,0,0] / 0 -> [] (full match) — the bare `let c: [3]u8;` zero-init
+	// row that surfaced #16 (a dirtied slot read non-zero, ltrim trimmed
+	// nothing). Now reads {0,0,0} and trims to empty.
+	let c: [3]u8;
+	assert(!(!beq(bytes.ltrim(c[0:3], 0u8), z[0:0])));
+
+	// [] / 0 -> [] (empty input)
+	assert(!(!beq(bytes.ltrim(z[0:0], 0u8), z[0:0])));
+};
+
+@test fn rtrim_cases() void = {
+	let z: [1]u8;
+
+	// [1,2,0,0] / 0 -> [1,2]
+	let a: [4]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 0u8; a[3] = 0u8;
+	let ea: [2]u8; ea[0] = 1u8; ea[1] = 2u8;
+	assert(!(!beq(bytes.rtrim(a[0:4], 0u8), ea[0:2])));
+
+	// [1,2,3] / 0 -> [1,2,3] (no trailing match)
+	let b: [3]u8; b[0] = 1u8; b[1] = 2u8; b[2] = 3u8;
+	assert(!(!beq(bytes.rtrim(b[0:3], 0u8), b[0:3])));
+
+	// [0,0,0] / 0 -> [] (full match)
+	let c: [3]u8;
+	assert(!(!beq(bytes.rtrim(c[0:3], 0u8), z[0:0])));
+
+	// [] / 0 -> [] (empty input)
+	assert(!(!beq(bytes.rtrim(z[0:0], 0u8), z[0:0])));
+};
+
+@test fn trim_cases() void = {
+	let z: [1]u8;
+
+	// [0,1,2,3,5,0] / 0 -> [1,2,3,5]
+	let a: [6]u8;
+	a[0] = 0u8; a[1] = 1u8; a[2] = 2u8;
+	a[3] = 3u8; a[4] = 5u8; a[5] = 0u8;
+	let ea: [4]u8; ea[0] = 1u8; ea[1] = 2u8; ea[2] = 3u8; ea[3] = 5u8;
+	assert(!(!beq(bytes.trim(a[0:6], 0u8), ea[0:4])));
+
+	// [0,5,0] / 5 -> [0,5,0] (only 5 in trim set; boundary mismatch)
+	let b: [3]u8; b[0] = 0u8; b[1] = 5u8; b[2] = 0u8;
+	assert(!(!beq(bytes.trim(b[0:3], 5u8), b[0:3])));
+
+	// [0,1,42,1,0] / {0,42} -> [1,42,1] (multi-byte trim set)
+	let c: [5]u8;
+	c[0] = 0u8; c[1] = 1u8; c[2] = 42u8; c[3] = 1u8; c[4] = 0u8;
+	let ec: [3]u8; ec[0] = 1u8; ec[1] = 42u8; ec[2] = 1u8;
+	assert(!(!beq(bytes.trim(c[0:5], 0u8, 42u8), ec[0:3])));
+
+	// [0,0,0] / 0 -> [] (full match)
+	let d: [3]u8;
+	assert(!(!beq(bytes.trim(d[0:3], 0u8), z[0:0])));
+
+	// [] / 0 -> [] (empty input, Hare ref/hare/bytes/trim.ha:34)
+	assert(!(!beq(bytes.trim(z[0:0], 0u8), z[0:0])));
+
+	// [1,2,3,5] / 0 -> [1,2,3,5] (Hare ref/hare/bytes/trim.ha:31)
+	let e: [4]u8; e[0] = 1u8; e[1] = 2u8; e[2] = 3u8; e[3] = 5u8;
+	assert(!(!beq(bytes.trim(e[0:4], 0u8), e[0:4])));
+};
diff --git a/test/byteid/libbyteid_test.ww b/test/byteid/libbyteid_test.ww
index 47f9ea00..9b10ed13 100644
--- a/test/byteid/libbyteid_test.ww
+++ b/test/byteid/libbyteid_test.ww
@@ -43,7 +43,7 @@ import time;
 def MID: i32 = 0;
 def MDIVERGE: i32 = 1;
 def MWWREJECT: i32 = 2;
-def NENTEXPECT: i32 = 51;
+def NENTEXPECT: i32 = 55;
 
 type ent = struct {
 	fixture: str,	// repo-relative .ww; "" -> probe entry
@@ -83,12 +83,16 @@ fn pri(p: str, inc: str, sentinel: str, moddir: str) ent = {
 	return e;
 };
 
-// The 51-unit roster. Graduation history lives in git (the retired C
+// The 55-unit roster. Graduation history lives in git (the retired C
 // carrier's table comments); cites are kept only where a non-ID pin
 // would need them.
 fn corpus() []ent = {
 	let es: []ent = alloc([], NENTEXPECT: u64)!;
-	append(es, fx("lib/bytes/bytes_test.ww"));
+	append(es, fx("lib/bytes/equal_test.ww"));
+	append(es, fx("lib/bytes/index_test.ww"));
+	append(es, fx("lib/bytes/contains_test.ww"));
+	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, fx("lib/encoding/hex/hex_test.ww"));