diff --git a/MC6809/MC6809.UnitTest/ComTests.cs b/MC6809/MC6809.UnitTest/ComTests.cs
new file mode 100644
index 0000000..511d54a
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/ComTests.cs
@@ -0,0 +1,60 @@
+// <copyright file="ComTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class ComTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public ComTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestCOM_direct()
+        {
+            this.board.Poke(0xb00, 0x03);
+            this.board.Poke(0xb01, 0x00);
+            this.board.Poke(0x0200, 0x07);
+            this.cpu.CC = 0;
+            this.cpu.DP = 2;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xf8, this.board.Peek(0x0200));
+            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.AreNotEqual(0, this.cpu.Carry);
+        }
+
+        [TestMethod]
+        public void TestCOM_a()
+        {
+            this.cpu.CC = 0;
+            this.cpu.A = 0x74;
+            this.board.Poke(0xb00, 0x43);
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0x8B, this.cpu.A);
+            Assert.AreEqual(0x09, this.cpu.CC);
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/LsrTests.cs b/MC6809/MC6809.UnitTest/LsrTests.cs
new file mode 100644
index 0000000..8280ca8
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/LsrTests.cs
@@ -0,0 +1,111 @@
+// <copyright file="LsrTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class LsrTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public LsrTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        // Logical Shift Right of 0x3E to 0x1F
+        [TestMethod]
+        public void TestLSR_a_one()
+        {
+            this.board.Poke(0xb00, 0x44);
+            this.cpu.CC = 0xf;
+            this.cpu.A = 0x3e;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0x1F, this.cpu.A);
+            Assert.AreEqual(2, this.cpu.CC);
+            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.AreEqual(0, this.cpu.Negative);
+        }
+
+        // Logical Shift Right of 1
+        [TestMethod]
+        public void TestLSR_a_two()
+        {
+            this.board.Poke(0xb00, 0x44);
+            this.cpu.CC &= (byte)~StatusBits.CF;
+            this.cpu.CC |= (byte)StatusBits.VF;
+            this.cpu.CC |= (byte)StatusBits.NF;
+            this.cpu.A = 1;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0, this.cpu.A);
+            Assert.AreNotEqual(0, this.cpu.Zero);
+            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.AreEqual(0, this.cpu.Negative);
+        }
+
+        // Logical Shift Right of 0xB8
+        [TestMethod]
+        public void TestLSR_a_three()
+        {
+            this.board.Poke(0xb00, 0x44);
+            this.cpu.CC &= (byte)~StatusBits.CF;
+            this.cpu.CC &= (byte)~StatusBits.VF;
+            this.cpu.A = 0xb8;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0x5c, this.cpu.A);
+            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.AreEqual(0, this.cpu.Carry);
+        }
+
+        // Shift a byte at 0x0402, because DP = 0x04.
+        [TestMethod]
+        public void TestLSR_direct()
+        {
+            this.board.Poke(0xb00, 0x4);
+            this.board.Poke(0xb01, 0x2);
+            this.cpu.PC.Word = 0xb00;
+            this.cpu.CC = 0;
+            this.cpu.A = 0;
+            this.cpu.B = 0;
+            this.cpu.DP = 4;
+            this.cpu.X.Word = 0;
+            this.cpu.Y.Word = 0;
+            this.cpu.S.Word = 0;
+            this.cpu.U.Word = 0;
+            this.board.Poke(0x0402, 0xf1);
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xb02, this.cpu.PC.Word);
+            Assert.AreEqual(1, this.cpu.CC);
+            Assert.AreEqual(0, this.cpu.A);
+            Assert.AreEqual(0, this.cpu.B);
+            Assert.AreEqual(4, this.cpu.DP);
+            Assert.AreEqual(0, this.cpu.X.Word);
+            Assert.AreEqual(0, this.cpu.Y.Word);
+            Assert.AreEqual(0, this.cpu.S.Word);
+            Assert.AreEqual(0, this.cpu.U.Word);
+            Assert.AreEqual(0x78, this.board.Peek(0x402));
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/MC6809.UnitTest.csproj b/MC6809/MC6809.UnitTest/MC6809.UnitTest.csproj
index 1a801ae..d057768 100644
--- a/MC6809/MC6809.UnitTest/MC6809.UnitTest.csproj
+++ b/MC6809/MC6809.UnitTest/MC6809.UnitTest.csproj
@@ -8,7 +8,7 @@
     <ProjectGuid>{4391A363-ECEF-44C8-9335-BF6ECB811E4B}</ProjectGuid>
     <OutputType>Library</OutputType>
     <AppDesignerFolder>Properties</AppDesignerFolder>
-    <RootNamespace>MC6809.UnitTest</RootNamespace>
+    <RootNamespace>EightBit</RootNamespace>
     <AssemblyName>MC6809.UnitTest</AssemblyName>
     <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
@@ -74,6 +74,14 @@
     <Compile Include="SbcTests.cs" />
     <Compile Include="SubTests.cs" />
     <Compile Include="TfrTests.cs" />
+    <Compile Include="PshTests.cs" />
+    <Compile Include="PulTests.cs" />
+    <Compile Include="TstTests.cs" />
+    <Compile Include="OrTests.cs" />
+    <Compile Include="RolTests.cs" />
+    <Compile Include="LsrTests.cs" />
+    <Compile Include="RorTests.cs" />
+    <Compile Include="ComTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\EightBit\EightBit.csproj">
diff --git a/MC6809/MC6809.UnitTest/OrTests.cs b/MC6809/MC6809.UnitTest/OrTests.cs
new file mode 100644
index 0000000..8a5d8b9
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/OrTests.cs
@@ -0,0 +1,42 @@
+// <copyright file="OrTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class OrTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public OrTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestORA_immediate()
+        {
+            this.cpu.CC = 0x43;
+            this.cpu.A = 0xda;
+            this.board.Poke(0xb00, 0x8a);
+            this.board.Poke(0xb01, 0x0f);
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xdf, this.cpu.A);
+            Assert.AreEqual(0x49, this.cpu.CC);
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/PshTests.cs b/MC6809/MC6809.UnitTest/PshTests.cs
new file mode 100644
index 0000000..2918934
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/PshTests.cs
@@ -0,0 +1,99 @@
+// <copyright file="PshTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class PshTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public PshTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestPSHS_all()
+        {
+            this.cpu.S.Word = 517;
+            this.cpu.CC = 0xf;
+            this.cpu.A = 1;
+            this.cpu.B = 2;
+            this.cpu.DP = 3;
+            this.cpu.X.Word = 0x405;
+            this.cpu.Y.Word = 0x607;
+            this.cpu.U.Word = 0x809;
+            this.cpu.PC.Word = 0xb00;
+            this.board.Poke(0xb00, 0x34);
+            this.board.Poke(0xb01, 0xff);
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xb02, this.cpu.PC.Word);
+            Assert.AreEqual(0xf, this.cpu.CC);
+            Assert.AreEqual(1, this.cpu.A);
+            Assert.AreEqual(2, this.cpu.B);
+            Assert.AreEqual(517 - 12, this.cpu.S.Word);
+            Assert.AreEqual(0x02, this.board.Peek(517 - 1));
+            Assert.AreEqual(0x0b, this.board.Peek(517 - 2));
+            Assert.AreEqual(0x09, this.board.Peek(517 - 3));
+            Assert.AreEqual(0x08, this.board.Peek(517 - 4));
+            Assert.AreEqual(0x07, this.board.Peek(517 - 5));
+            Assert.AreEqual(0x06, this.board.Peek(517 - 6));
+            Assert.AreEqual(0x05, this.board.Peek(517 - 7));
+            Assert.AreEqual(0x04, this.board.Peek(517 - 8));
+            Assert.AreEqual(0x03, this.board.Peek(517 - 9));
+            Assert.AreEqual(0x02, this.board.Peek(517 - 10));
+            Assert.AreEqual(0x01, this.board.Peek(517 - 11));
+            Assert.AreEqual(0x0f, this.board.Peek(517 - 12));
+        }
+
+        [TestMethod]
+        public void TestPSHU_all()
+        {
+            this.cpu.U.Word = 517;
+            this.cpu.CC = 0xf;
+            this.cpu.A = 1;
+            this.cpu.B = 2;
+            this.cpu.DP = 3;
+            this.cpu.X.Word = 0x405;
+            this.cpu.Y.Word = 0x607;
+            this.cpu.S.Word = 0x809;
+            this.cpu.PC.Word = 0xb00;
+            this.board.Poke(0xb00, 0x36);
+            this.board.Poke(0xb01, 0xff);
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xb02, this.cpu.PC.Word);
+            Assert.AreEqual(0xf, this.cpu.CC);
+            Assert.AreEqual(1, this.cpu.A);
+            Assert.AreEqual(2, this.cpu.B);
+            Assert.AreEqual(517 - 12, this.cpu.U.Word);
+            Assert.AreEqual(0x02, this.board.Peek(517 - 1));
+            Assert.AreEqual(0x0b, this.board.Peek(517 - 2));
+            Assert.AreEqual(0x09, this.board.Peek(517 - 3));
+            Assert.AreEqual(0x08, this.board.Peek(517 - 4));
+            Assert.AreEqual(0x07, this.board.Peek(517 - 5));
+            Assert.AreEqual(0x06, this.board.Peek(517 - 6));
+            Assert.AreEqual(0x05, this.board.Peek(517 - 7));
+            Assert.AreEqual(0x04, this.board.Peek(517 - 8));
+            Assert.AreEqual(0x03, this.board.Peek(517 - 9));
+            Assert.AreEqual(0x02, this.board.Peek(517 - 10));
+            Assert.AreEqual(0x01, this.board.Peek(517 - 11));
+            Assert.AreEqual(0x0f, this.board.Peek(517 - 12));
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/PulTests.cs b/MC6809/MC6809.UnitTest/PulTests.cs
new file mode 100644
index 0000000..74f628d
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/PulTests.cs
@@ -0,0 +1,106 @@
+// <copyright file="PulTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class PulTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public PulTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestPULS_all()
+        {
+            this.board.Poke(512 - 12, 0x00);
+            this.board.Poke(512 - 11, 0x11);
+            this.board.Poke(512 - 10, 0x12);
+            this.board.Poke(512 - 9, 0x13);
+            this.cpu.PokeWord(512 - 8, 0x9141);
+            this.cpu.PokeWord(512 - 6, 0xa142);
+            this.cpu.PokeWord(512 - 4, 0xb140);
+            this.cpu.PokeWord(512 - 2, 0x04ff);
+            this.cpu.Y.Word = 0x1115;
+            this.cpu.S.Word = 500;
+            this.cpu.CC = 0xf;
+            this.board.Poke(0xb00, 0x35);
+            this.board.Poke(0xb01, 0xff);
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0, this.cpu.CC);
+            Assert.AreEqual(0x11, this.cpu.A);
+            Assert.AreEqual(0x12, this.cpu.B);
+            Assert.AreEqual(0x13, this.cpu.DP);
+            Assert.AreEqual(0x9141, this.cpu.X.Word);
+            Assert.AreEqual(0xa142, this.cpu.Y.Word);
+            Assert.AreEqual(0xb140, this.cpu.U.Word);
+            Assert.AreEqual(0x4ff, this.cpu.PC.Word);
+        }
+
+        [TestMethod]
+        public void TestPULU_all()
+        {
+            this.board.Poke(512 - 12, 0x00);
+            this.board.Poke(512 - 11, 0x11);
+            this.board.Poke(512 - 10, 0x12);
+            this.board.Poke(512 - 9, 0x13);
+            this.cpu.PokeWord(512 - 8, 0x9141);
+            this.cpu.PokeWord(512 - 6, 0xa142);
+            this.cpu.PokeWord(512 - 4, 0xb140);
+            this.cpu.PokeWord(512 - 2, 0x04ff);
+            this.cpu.Y.Word = 0x1115;
+            this.cpu.U.Word = 500;
+            this.cpu.CC = 0xf;
+            this.board.Poke(0xb00, 0x37);
+            this.board.Poke(0xb01, 0xff);
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0, this.cpu.CC);
+            Assert.AreEqual(0x11, this.cpu.A);
+            Assert.AreEqual(0x12, this.cpu.B);
+            Assert.AreEqual(0x13, this.cpu.DP);
+            Assert.AreEqual(0x9141, this.cpu.X.Word);
+            Assert.AreEqual(0xa142, this.cpu.Y.Word);
+            Assert.AreEqual(0xb140, this.cpu.S.Word);
+            Assert.AreEqual(0x4ff, this.cpu.PC.Word);
+        }
+
+        [TestMethod]
+        public void TestPULS_y()
+        {
+            this.cpu.PokeWord(0x205, 0xb140);
+            this.cpu.PokeWord(0x207, 0x04ff);
+            this.cpu.Y.Word = 0x1115;
+            this.cpu.S.Word = 0x205;
+            this.cpu.CC = 0xf;
+            this.board.Poke(0xb00, 0x35);
+            this.board.Poke(0xb01, 0xa0);
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xb140, this.cpu.Y.Word);
+            Assert.AreEqual(0x4ff, this.cpu.PC.Word);
+            Assert.AreEqual(0xf, this.cpu.CC);
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/RolTests.cs b/MC6809/MC6809.UnitTest/RolTests.cs
new file mode 100644
index 0000000..a214b69
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/RolTests.cs
@@ -0,0 +1,79 @@
+// <copyright file="RolTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class RolTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public RolTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestROLB_inherent_one()
+        {
+            this.board.Poke(0xB00, 0x59);
+            this.cpu.B = 0x89;
+            this.cpu.CC = 0;
+            this.cpu.CC |= (byte)StatusBits.NF;
+            this.cpu.CC |= (byte)StatusBits.CF;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xb01, this.cpu.PC.Word);
+            Assert.AreEqual(0x13, this.cpu.B);
+            Assert.AreEqual(0x3, this.cpu.CC);
+            Assert.AreNotEqual(0, this.cpu.Carry);
+        }
+
+        [TestMethod]
+        public void TestROLB_inherent_two()
+        {
+            this.board.Poke(0xB00, 0x59);
+            this.cpu.CC = 0;
+            this.cpu.CC |= (byte)StatusBits.CF;
+            this.cpu.CC |= (byte)StatusBits.VF;
+            this.cpu.B = 1;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0x3, this.cpu.B);
+            Assert.AreEqual(0, this.cpu.CC);
+        }
+
+        [TestMethod]
+        public void TestROLB_inherent_three()
+        {
+            this.board.Poke(0xB00, 0x59);
+            this.cpu.CC = 0;
+            this.cpu.B = 0xd8;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xb0, this.cpu.B);
+            Assert.AreEqual(9, this.cpu.CC);
+            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.AreNotEqual(0, this.cpu.Negative);
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/RorTests.cs b/MC6809/MC6809.UnitTest/RorTests.cs
new file mode 100644
index 0000000..012d45f
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/RorTests.cs
@@ -0,0 +1,61 @@
+// <copyright file="RorTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class RorTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public RorTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestRORB_inherent_one()
+        {
+            this.board.Poke(0xb00, 0x56);
+            this.cpu.B = 0x89;
+            this.cpu.CC = 0;
+            this.cpu.CC |= (byte)StatusBits.CF;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xc4, this.cpu.B);
+            Assert.AreEqual(9, this.cpu.CC);
+            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.AreNotEqual(0, this.cpu.Negative);
+        }
+
+        [TestMethod]
+        public void TestRORB_inherent_two()
+        {
+            this.board.Poke(0xb00, 0x56);
+            this.cpu.B = 0x89;
+            this.cpu.CC = 0;
+            this.cpu.CC &= (byte)~StatusBits.CF;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0x44, this.cpu.B);
+            Assert.AreEqual(1, this.cpu.CC);
+            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.AreEqual(0, this.cpu.Negative);
+        }
+    }
+}
diff --git a/MC6809/MC6809.UnitTest/TstTests.cs b/MC6809/MC6809.UnitTest/TstTests.cs
new file mode 100644
index 0000000..fda0837
--- /dev/null
+++ b/MC6809/MC6809.UnitTest/TstTests.cs
@@ -0,0 +1,90 @@
+// <copyright file="TstTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class TstTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public TstTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestTSTA_inherent_one()
+        {
+            this.board.Poke(0xb00, 0x4D);
+            this.cpu.CC = 0;
+            this.cpu.A = 0xff;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xff, this.cpu.A);
+            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.AreEqual(0, this.cpu.Overflow);
+        }
+
+        [TestMethod]
+        public void TestTSTA_inherent_two()
+        {
+            this.board.Poke(0xb00, 0x4D);
+            this.cpu.CC = 0;
+            this.cpu.CC |= (byte)StatusBits.VF;
+            this.cpu.A = 0x01;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0x01, this.cpu.A);
+            Assert.AreEqual(0, this.cpu.CC);
+        }
+
+        [TestMethod]
+        public void TestTSTA_inherent_three()
+        {
+            this.board.Poke(0xb00, 0x4D);
+            this.cpu.CC = 0;
+            this.cpu.A = 0;
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.AreNotEqual(0, this.cpu.Zero);
+            Assert.AreEqual(0, this.cpu.Overflow);
+        }
+
+        [TestMethod]
+        public void TestTSTA_indirect()
+        {
+            this.board.Poke(0x205, 0xff);
+            this.cpu.Y.Word = 0x205;
+            this.board.Poke(0xb00, 0x6d);
+            this.board.Poke(0xb01, 0xa4);
+            this.cpu.PC.Word = 0xb00;
+
+            this.cpu.Step();
+
+            Assert.AreEqual(0xff, this.board.Peek(0x205));
+            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.AreEqual(0, this.cpu.Overflow);
+        }
+    }
+}