diff --git a/test/all.dart b/test/all.dart
index 9ce4efc..e9d9ddf 100644
--- a/test/all.dart
+++ b/test/all.dart
@@ -1,11 +1,9 @@
 import 'test_blake3.dart' as test_blake3;
 import 'test_ed448.dart' as test_ed448;
 import 'test_jwt.dart' as test_jwt;
-import 'test_sha3.dart' as test_sha3;
 
 main() {
   test_blake3.test();
   test_ed448.test();
   test_jwt.test();
-  test_sha3.test();
 }
diff --git a/test/test_sha3.dart b/test/test_sha3.dart
index 72a38c4..7798077 100644
--- a/test/test_sha3.dart
+++ b/test/test_sha3.dart
@@ -1,40 +1,121 @@
 import 'dart:convert';
 
-import '../lib/sha3.dart';
-
-test() {
-  var output = shake_128Hex(utf8.encode("abc"), 32);
-  print(output);
-  assert(output ==
-      "5881092dd818bf5cf8a3ddb793fbcba74097d5c526a6d35f97b83351940f2cc8");
-
-  output = shake_256Hex(utf8.encode("abc"), 64);
-  print(output);
-  assert(output ==
-      "483366601360a8771c6863080cc4114d8db44530f8f1e1ee4f94ea37e78b5739d5a15bef186a5386c75744c0527e1faa9f8726e462a12a4feb06bd8801e751e4");
-
-  output = sha3_224Hex(utf8.encode("abc"));
-  print(output);
-  assert(output == "e642824c3f8cf24ad09234ee7d3c766fc9a3a5168d0c94ad73b46fdf");
-
-  output = sha3_256Hex(utf8.encode("abc"));
-  print(output);
-  assert(output ==
-      "3a985da74fe225b2045c172d6bd390bd855f086e3e9d525b46bfe24511431532");
-
-  output = sha3_384Hex(utf8.encode("abc"));
-  print(output);
-  assert(output ==
-      "ec01498288516fc926459f58e2c6ad8df9b473cb0fc08c2596da7cf0e49be4b298d88cea927ac7f539f1edf228376d25");
-
-  output = sha3_512Hex(utf8.encode("abc"));
-  print(output);
-  assert(output ==
-      "b751850b1a57168a5693cd924b6b096e08f621827444f70d884f5d0240d2712e10e116e9192af3c91a7ec57647e3934057340b4cf408d5a56592f8274eec53f0");
-
-  // TODO Add more tests
-}
+import 'package:flutter_ed448/sha3.dart';
+import 'package:test/test.dart';
+
+List<int> _pattern(int length) => List<int>.generate(length, (i) => i % 251);
+
+String _hex(List<int> bytes) =>
+    bytes.map((byte) => byte.toRadixString(16).padLeft(2, '0')).join();
+
+void main() {
+  group('SHA-3 known-answer vectors', () {
+    test('matches all digest sizes for abc', () {
+      final input = utf8.encode('abc');
+      expect(
+        sha3_224Hex(input),
+        'e642824c3f8cf24ad09234ee7d3c766fc9a3a5168d0c94ad73b46fdf',
+      );
+      expect(
+        sha3_256Hex(input),
+        '3a985da74fe225b2045c172d6bd390bd855f086e3e9d525b46bfe24511431532',
+      );
+      expect(
+        sha3_384Hex(input),
+        'ec01498288516fc926459f58e2c6ad8df9b473cb0fc08c2596da7cf0e49be4b2'
+        '98d88cea927ac7f539f1edf228376d25',
+      );
+      expect(
+        sha3_512Hex(input),
+        'b751850b1a57168a5693cd924b6b096e08f621827444f70d884f5d0240d2712e1'
+        '0e116e9192af3c91a7ec57647e3934057340b4cf408d5a56592f8274eec53f0',
+      );
+    });
+
+    test('matches empty-input vectors', () {
+      expect(
+        sha3_224Hex(const []),
+        '6b4e03423667dbb73b6e15454f0eb1abd4597f9a1b078e3f5b5a6bc7',
+      );
+      expect(
+        sha3_256Hex(const []),
+        'a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a',
+      );
+      expect(
+        sha3_384Hex(const []),
+        '0c63a75b845e4f7d01107d852e4c2485c51a50aaaa94fc61995e71bbee983a2a'
+        'c3713831264adb47fb6bd1e058d5f004',
+      );
+      expect(
+        sha3_512Hex(const []),
+        'a69f73cca23a9ac5c8b567dc185a756e97c982164fe25859e0d1dcc1475c80a6'
+        '15b2123af1f5f94c11e3e9402c3ac558f500199d95b6d3e301758586281dcd26',
+      );
+    });
+
+    test('handles the SHA3-256 rate boundary', () {
+      const expected = {
+        135: 'fded8fd9d6551c601eeb3b7c6bc5e5cfd8aad1d015b7e9aaa9c9b9475231d5e2',
+        136: 'cf3ccff92480a29160c2d38317c430e14749bfee1788106957dfe73f8c4930e5',
+        137: 'ce9d7dc90913ee5d92745019479a5352c6d6279bef18ed07dc0a83ee8084daca',
+      };
+
+      for (final entry in expected.entries) {
+        expect(sha3_256Hex(_pattern(entry.key)), entry.value);
+      }
+    });
+
+    test('handles multi-block input', () {
+      expect(
+        sha3_512Hex(_pattern(4096)),
+        'ac8fc5c0a7dc20b9234524accd6000bcafbad2850a66455600873c13d1cb6875'
+        '824f6888630829896eb411ee4973896e0fb6487d8be89fcc3dfd9eed6c93fe90',
+      );
+    });
+  });
+
+  group('SHAKE extendable output', () {
+    test('matches known vectors', () {
+      expect(
+        shake_128Hex(utf8.encode('abc'), 32),
+        '5881092dd818bf5cf8a3ddb793fbcba74097d5c526a6d35f97b83351940f2cc8',
+      );
+      expect(
+        shake_256Hex(utf8.encode('abc'), 64),
+        '483366601360a8771c6863080cc4114d8db44530f8f1e1ee4f94ea37e78b5739'
+        'd5a15bef186a5386c75744c0527e1faa9f8726e462a12a4feb06bd8801e751e4',
+      );
+      expect(
+        shake_128Hex(const [], 32),
+        '7f9c2ba4e88f827d616045507605853ed73b8093f6efbc88eb1a6eacfa66ef26',
+      );
+    });
+
+    test('supports zero and variable-length output', () {
+      expect(shake_128Hex(const [], 0), isEmpty);
+      final shortDigest = shake_256Hex(utf8.encode('abc'), 16);
+      final longDigest = shake_256Hex(utf8.encode('abc'), 64);
+      expect(shortDigest.length, 32);
+      expect(longDigest.length, 128);
+      expect(longDigest, startsWith(shortDigest));
+    });
+
+    test('handles the SHAKE128 rate boundary', () {
+      const expected = {
+        167: '1e552791cc4e93a0d4a8dc47ae49228c2faa869e40e628f6ace477aec3f1ca7a',
+        168: 'f15277eb61c4908d44a2853f3cde071ae2ed7a23461fbe162a1a98cf6875059c',
+        169: '015be3338c986d9846affa0f94b4afc2a76bc289c709e1a596ec9eccf090a773',
+      };
+
+      for (final entry in expected.entries) {
+        expect(shake_128Hex(_pattern(entry.key), 32), entry.value);
+      }
+    });
+  });
 
-main() {
-  test();
+  test('byte and hexadecimal APIs agree', () {
+    final input = utf8.encode('Tone');
+    expect(_hex(sha3_256(input)), sha3_256Hex(input));
+    expect(_hex(shake_256(input, 48)), shake_256Hex(input, 48));
+  });
 }