test(core): add debugger and watchpoint tests

tests/Chip8.Tests/WatchpointTests.cs

@@ -0,0 +1,101 @@
+using Chip8.Core;
+using Xunit;
+
+namespace Chip8.Tests;
+
+public class WatchpointTests
+{
+    [Fact]
+    public void memoryWatchStopsWhenTheByteChanges()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0xA400, 0x6005, 0xF055, 0x1206);
+        var debugger = new Debugger(machine);
+        debugger.watchMemory(0x400);
+
+        RunResult outcome = debugger.run(100);
+
+        Assert.Equal(StopReason.Watchpoint, outcome.reason);
+        Assert.Equal(3, outcome.steps);
+        Assert.Equal(0x400, outcome.triggeredAddress);
+        Assert.Equal(5, machine.memory[0x400]);
+        Assert.Contains("memory 0x0400", debugger.lastWatchDescription);
+    }
+
+    [Fact]
+    public void registerWatchStopsWhenTheRegisterChanges()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0x6005, 0x1202);
+        var debugger = new Debugger(machine);
+        debugger.watchRegister(0);
+
+        RunResult outcome = debugger.run(50);
+
+        Assert.Equal(StopReason.Watchpoint, outcome.reason);
+        Assert.Equal(1, outcome.steps);
+        Assert.Contains("V0", debugger.lastWatchDescription);
+    }
+
+    [Fact]
+    public void unwatchedMemoryDoesNotStop()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0xA400, 0x6005, 0xF055, 0x1206);
+        var debugger = new Debugger(machine);
+        debugger.watchMemory(0x400);
+        debugger.clearWatches();
+
+        RunResult outcome = debugger.run(20);
+
+        Assert.Equal(StopReason.StepLimit, outcome.reason);
+    }
+
+    [Fact]
+    public void stepOverRunsThroughACall()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0x2204, 0x6042, 0x0000, 0x00EE);
+        var debugger = new Debugger(machine);
+
+        RunResult outcome = debugger.stepOver(100);
+
+        Assert.Equal(0x202, machine.pc);
+        Assert.Equal(0, machine.v[0]);
+        Assert.Equal(3, outcome.steps);
+    }
+
+    [Fact]
+    public void stepOverIsASingleStepForNonCalls()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0x6005, 0x1202);
+        var debugger = new Debugger(machine);
+
+        debugger.stepOver(100);
+
+        Assert.Equal(0x202, machine.pc);
+        Assert.Equal(5, machine.v[0]);
+    }
+
+    [Fact]
+    public void runUntilStopsAtTheTargetAddress()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0x7001, 0x1200);
+        var debugger = new Debugger(machine);
+
+        RunResult outcome = debugger.runUntil(0x202, 100);
+
+        Assert.Equal(0x202, machine.pc);
+        Assert.Equal(StopReason.Breakpoint, outcome.reason);
+    }
+
+    [Fact]
+    public void disassembleWindowDecodesFromProgramCounter()
+    {
+        var machine = TestHarness.withProgram(Platform.Chip8, 0xA300, 0x6001, 0x00EE);
+        var debugger = new Debugger(machine);
+
+        var lines = debugger.disassembleWindow(3);
+
+        Assert.Equal(3, lines.Count);
+        Assert.Equal(0x200, lines[0].address);
+        Assert.Equal("LD I, 0x300", lines[0].mnemonic);
+        Assert.Equal("RET", lines[2].mnemonic);
+    }
+}