diff --git a/src/Geralt.Tests/BLAKE2bTests.cs b/src/Geralt.Tests/BLAKE2bTests.cs
index a53b95b..6e6cae2 100644
--- a/src/Geralt.Tests/BLAKE2bTests.cs
+++ b/src/Geralt.Tests/BLAKE2bTests.cs
@@ -314,7 +314,13 @@ public void Incremental_Valid(string hash, string message, string? key = null)
         Span<byte> k = key != null ? Convert.FromHexString(key) : Span<byte>.Empty;
 
         using var blake2b = new IncrementalBLAKE2b(h.Length, k);
-        blake2b.Update(m);
+        if (m.Length > 1) {
+            blake2b.Update(m[..(m.Length / 2)]);
+            blake2b.Update(m[(m.Length / 2)..]);
+        }
+        else {
+            blake2b.Update(m);
+        }
         blake2b.Finalize(h);
 
         Assert.AreEqual(hash, Convert.ToHexString(h).ToLower());
diff --git a/src/Geralt.Tests/Ed25519Tests.cs b/src/Geralt.Tests/Ed25519Tests.cs
index b4a7466..f250170 100644
--- a/src/Geralt.Tests/Ed25519Tests.cs
+++ b/src/Geralt.Tests/Ed25519Tests.cs
@@ -309,7 +309,13 @@ public void Incremental_Sign_Valid(string signature, string message, string priv
         Span<byte> sk = Convert.FromHexString(privateKey);
 
         using var ed25519ph = new IncrementalEd25519();
-        ed25519ph.Update(m);
+        if (m.Length > 1) {
+            ed25519ph.Update(m[..(m.Length / 2)]);
+            ed25519ph.Update(m[(m.Length / 2)..]);
+        }
+        else {
+            ed25519ph.Update(m);
+        }
         ed25519ph.Finalize(s, sk);
 
         Assert.AreEqual(signature, Convert.ToHexString(s).ToLower());
@@ -338,7 +344,13 @@ public void Incremental_Verify_Valid(string signature, string message, string pr
         Span<byte> pk = Convert.FromHexString(privateKey)[^Ed25519.PublicKeySize..];
 
         using var ed25519ph = new IncrementalEd25519();
-        ed25519ph.Update(m);
+        if (m.Length > 1) {
+            ed25519ph.Update(m[..(m.Length / 2)]);
+            ed25519ph.Update(m[(m.Length / 2)..]);
+        }
+        else {
+            ed25519ph.Update(m);
+        }
 
         bool valid = ed25519ph.Verify(s, pk);
 
diff --git a/src/Geralt.Tests/Poly1305Tests.cs b/src/Geralt.Tests/Poly1305Tests.cs
index bc709bb..536c70c 100644
--- a/src/Geralt.Tests/Poly1305Tests.cs
+++ b/src/Geralt.Tests/Poly1305Tests.cs
@@ -116,7 +116,13 @@ public void Incremental_Valid(string tag, string message, string oneTimeKey)
         Span<byte> k = Convert.FromHexString(oneTimeKey);
 
         using var poly1305 = new IncrementalPoly1305(k);
-        poly1305.Update(m);
+        if (m.Length > 1) {
+            poly1305.Update(m[..(m.Length / 2)]);
+            poly1305.Update(m[(m.Length / 2)..]);
+        }
+        else {
+            poly1305.Update(m);
+        }
         poly1305.Finalize(t);
 
         Assert.AreEqual(tag, Convert.ToHexString(t).ToLower());