test(core): add machine state and ROM loading tests

tests/Chip8.Tests/RomTests.cs

@@ -0,0 +1,36 @@
+using Chip8.Core;
+using Xunit;
+
+namespace Chip8.Tests;
+
+public class RomTests
+{
+    [Theory]
+    [InlineData("2-ibm-logo.ch8", 40, "ibm.txt", 230)]
+    [InlineData("3-corax+.ch8", 500, "corax.txt", 503)]
+    [InlineData("4-flags.ch8", 1000, "flags.txt", 495)]
+    [InlineData("test_opcode.ch8", 3000, "opcode.txt", 626)]
+    [InlineData("BC_test.ch8", 4000, "bctest.txt", 172)]
+    public void romRendersExpectedFramebuffer(string rom, int cycles, string golden, int litPixels)
+    {
+        var machine = TestHarness.runRom(rom, cycles);
+        string rendered = AsciiScreen.render(machine.display);
+
+        Assert.Equal(litPixels, AsciiScreen.litPixelCount(machine.display));
+        Assert.Equal(TestHarness.goldenText(golden), rendered);
+    }
+
+    [Fact]
+    public void corax89PassesUnderCosmacQuirksToo()
+    {
+        var machine = TestHarness.runRom("test_opcode.ch8", 3000, Quirks.cosmacVip());
+        Assert.Equal(TestHarness.goldenText("opcode.txt"), AsciiScreen.render(machine.display));
+    }
+
+    [Fact]
+    public void beepRomActivatesSoundTimer()
+    {
+        var machine = TestHarness.runRom("7-beep.ch8", 40);
+        Assert.True(machine.soundActive);
+    }
+}