diff --git a/exercises/hamming/uHammingExample.pas b/exercises/hamming/uHammingExample.pas
index f9459dfb..22511ac0 100644
--- a/exercises/hamming/uHammingExample.pas
+++ b/exercises/hamming/uHammingExample.pas
@@ -12,12 +12,18 @@ implementation
 uses System.SysUtils;
 
 class function THamming.Distance(strand1, strand2: string): integer;
-var i: integer;
 begin
+  if strand1.IsEmpty and not strand2.IsEmpty then
+    raise EArgumentException.Create('error: left strand must not be empty');
+
+  if not strand1.IsEmpty and strand2.IsEmpty then
+    raise EArgumentException.Create('error: right strand must not be empty');
+
   if strand1.Length <> strand2.Length  then
     raise EArgumentException.Create('error: left and right strands must be of equal length');
+
   result := 0;
-  for i := Low(strand1) to High(strand1) do
+  for var i := Low(strand1) to High(strand1) do
     result := result + ord(strand1[i] <> strand2[i]);
 end;
 
diff --git a/exercises/hamming/uHammingTests.pas b/exercises/hamming/uHammingTests.pas
index 46f84ec7..74fdccde 100644
--- a/exercises/hamming/uHammingTests.pas
+++ b/exercises/hamming/uHammingTests.pas
@@ -5,14 +5,14 @@ interface
   DUnitX.TestFramework;
 
 const
-  CanonicalVersion = '2.2.0';
+  CanonicalVersion = '2.3.0';
 
 type
   [TestFixture]
   HammingTests = class(TObject)
   public
     [Test]
-//  [Ignore('Comment the "[Ignore]" statement to run the test')]
+//    [Ignore('Comment the "[Ignore]" statement to run the test')]
     procedure empty_strands;
 
     [Test]
@@ -38,6 +38,14 @@   HammingTests = class(TObject)
     [Test]
     [Ignore]
     procedure disallow_second_strand_longer;
+
+    [Test]
+    [Ignore]
+    procedure disallow_left_empty_strand;
+
+    [Test]
+    [Ignore]
+    procedure disallow_right_empty_strand;
   end;
 
 implementation
@@ -78,6 +86,26 @@ procedure HammingTests.disallow_first_strand_longer;
   Assert.WillRaiseWithMessage(MyProc, EArgumentException, 'error: left and right strands must be of equal length');
 end;
 
+procedure HammingTests.disallow_left_empty_strand;
+var MyProc: TTestLocalMethod;
+begin
+  MyProc := procedure
+            begin
+              THamming.Distance('', 'G');
+            end;
+  Assert.WillRaiseWithMessage(MyProc, EArgumentException, 'error: left strand must not be empty');
+end;
+
+procedure HammingTests.disallow_right_empty_strand;
+var MyProc: TTestLocalMethod;
+begin
+  MyProc := procedure
+            begin
+              THamming.Distance('G', '');
+            end;
+  Assert.WillRaiseWithMessage(MyProc, EArgumentException, 'error: right strand must not be empty');
+end;
+
 procedure HammingTests.disallow_second_strand_longer;
 var MyProc: TTestLocalMethod;
 begin