diff --git a/src/BizHawk.Common/checksums/SHA256Checksum.cs b/src/BizHawk.Common/checksums/SHA256Checksum.cs
index 63199db60d..f27d9b53ff 100644
--- a/src/BizHawk.Common/checksums/SHA256Checksum.cs
+++ b/src/BizHawk.Common/checksums/SHA256Checksum.cs
@@ -17,6 +17,8 @@ namespace BizHawk.Common
 
 		internal const string PREFIX = "SHA256";
 
+		public /*static readonly*/const string EmptyFile = "E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855";
+
 #if NET6_0
 		public static byte[] Compute(ReadOnlySpan<byte> data)
 			=> SHA256.HashData(data);
diff --git a/src/BizHawk.Tests/Client.Common/Api/MemoryApiTests.cs b/src/BizHawk.Tests/Client.Common/Api/MemoryApiTests.cs
index b127bd8fc6..ec6c5f1453 100644
--- a/src/BizHawk.Tests/Client.Common/Api/MemoryApiTests.cs
+++ b/src/BizHawk.Tests/Client.Common/Api/MemoryApiTests.cs
@@ -3,6 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 
+using BizHawk.Common;
 using BizHawk.Client.Common;
 using BizHawk.Emulation.Common;
 
@@ -15,7 +16,12 @@ namespace BizHawk.Tests.Client.Common.Api
 	{
 		/// <remarks><see cref="CollectionAssert.AreEqual(ICollection, ICollection)"/> and its overloads can't take <see cref="IReadOnlyCollection{T}"/> -_-</remarks>
 		private static void AssertAreSequenceEqual<T>(IReadOnlyList<T> expected, IReadOnlyList<T> actual, string message)
-			=> Assert.IsTrue(actual.SequenceEqual(expected), message);
+		{
+			if (actual.SequenceEqual(expected)) return;
+			Console.WriteLine($"ex[{expected.Count}]: {string.Join(", ", expected.Select(static o => o?.ToString() ?? "null"))}");
+			Console.WriteLine($"ac[{actual.Count}]: {string.Join(", ", actual.Select(static o => o?.ToString() ?? "null"))}");
+			Assert.Fail(message);
+		}
 
 		private IMemoryApi CreateDummyApi(byte[] memDomainContents)
 			=> new MemoryApi(Console.WriteLine) //TODO capture and check for error messages?
@@ -106,5 +112,38 @@ namespace BizHawk.Tests.Client.Common.Api
 				memApi => memApi.WriteByteRange(9, new byte[] { 0x01, 0x23, 0x45, 0x67 }),
 				"fully above upper boundary");
 		}
+
+		[TestMethod]
+		public void TestHash()
+		{
+			var memApi = CreateDummyApi(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
+			Assert.ThrowsException<ArgumentOutOfRangeException>(
+				() => memApi.HashRegion(addr: -5, count: 3),
+				"fully below lower boundary");
+			Assert.ThrowsException<ArgumentOutOfRangeException>(
+				() => memApi.HashRegion(addr: -2, count: 4),
+				"crosses lower boundary");
+			Assert.ThrowsException<ArgumentOutOfRangeException>(
+				() => memApi.HashRegion(addr: -1, count: 10),
+				"crosses both boundaries");
+			Assert.AreEqual(
+				"55C53F5D490297900CEFA825D0C8E8E9532EE8A118ABE7D8570762CD38BE9818",
+				memApi.HashRegion(addr: 0, count: 8),
+				"whole domain");
+			Assert.AreEqual(
+				"233ABF8F525463C943A10F4DC3080B1BDA19D2EEAA4ACF4676F44689CED29232",
+				memApi.HashRegion(addr: 1, count: 5),
+				"strict contains");
+			Assert.AreEqual(
+				SHA256Checksum.EmptyFile,
+				memApi.HashRegion(addr: 3, count: 0),
+				"empty");
+			Assert.ThrowsException<ArgumentOutOfRangeException>(
+				() => memApi.HashRegion(addr: 6, count: 3),
+				"crosses upper boundary");
+			Assert.ThrowsException<ArgumentOutOfRangeException>(
+				() => memApi.HashRegion(addr: 9, count: 4),
+				"fully above upper boundary");
+		}
 	}
 }