godosa-engine: initial public history

1 files changed, 149 insertions, 0 deletions

diff --git a/src/Godosa.Core.Tests/Runs/RunsTests.cs b/src/Godosa.Core.Tests/Runs/RunsTests.cs
new file mode 100644
index 0000000..1b6d6d4
--- /dev/null
+++ b/src/Godosa.Core.Tests/Runs/RunsTests.cs
@@ -0,0 +1,149 @@
+using Godosa.Core.Runs;
+using Xunit;
+
+namespace Godosa.Core.Tests.Runs;
+
+public class RunsTests
+{
+    private static RunFlags Parse(params string[] args)
+    {
+        var flags = new RunFlags();
+        for (var i = 0; i < args.Length; i++)
+            Assert.True(RunFlags.TryTake(args, ref i, ref flags), args[i]);
+        return flags;
+    }
+
+    [Fact]
+    public void Flags_DeterministicWithAndWithoutSeed()
+    {
+        Assert.Equal(new RunFlags(Deterministic: true, Seed: 7), Parse("--deterministic", "7"));
+        Assert.Equal(new RunFlags(Deterministic: true), Parse("--deterministic"));
+        Assert.Equal(1UL, Parse("--deterministic").SeedOr(1));
+        Assert.Equal(7UL, Parse("--deterministic", "7").SeedOr(1));
+    }
+
+    [Fact]
+    public void Flags_SeedNotTakenWhenNextIsAnOption()
+    {
+        string[] args = ["--deterministic", "--mute"];
+        var flags = new RunFlags();
+        var i = 0;
+        Assert.True(RunFlags.TryTake(args, ref i, ref flags));
+        Assert.Equal(0, i);
+        i = 1;
+        Assert.False(RunFlags.TryTake(args, ref i, ref flags));
+    }
+
+    [Fact]
+    public void Flags_DigestEveryAndHeadless()
+    {
+        Assert.Equal(new RunFlags(Digest: true), Parse("--digest"));
+        Assert.Equal(new RunFlags(Digest: true, DigestEvery: 60), Parse("--digest", "every=60"));
+        Assert.Equal(new RunFlags(Deterministic: true, Headless: true), Parse("--headless"));
+        Assert.Equal(new RunFlags(Deterministic: true, Seed: 3, Headless: true), Parse("--headless", "--deterministic", "3"));
+    }
+
+    [Fact]
+    public void Flags_BadDigestEvery_Throws() =>
+        Assert.Throws<ArgumentException>(() => Parse("--digest", "every=0"));
+
+    [Fact]
+    public void Clock_DeterministicFixedStep()
+    {
+        var clock = new FrameClock(true);
+        Assert.Equal(1.0 / 60, clock.Next(0.5));
+        Assert.Equal(1.0 / 60, clock.Next(0.001));
+        Assert.Equal(2, clock.Frame);
+        Assert.Equal(2.0 / 60, clock.Seconds, 12);
+    }
+
+    [Fact]
+    public void Clock_WallClamped()
+    {
+        var clock = new FrameClock(false);
+        Assert.Equal(0.1, clock.Next(0.5));
+        Assert.Equal(0.02, clock.Next(0.02));
+        Assert.Equal(0, clock.Next(-1));
+        Assert.Equal(3, clock.Frame);
+    }
+
+    [Fact]
+    public void Clock_Held_NoTimeNoFrame()
+    {
+        var clock = new FrameClock(true) { Held = true };
+        Assert.Equal(0, clock.Next(1.0 / 60));
+        Assert.Equal(0, clock.Frame);
+        Assert.Equal(0, clock.Seconds);
+        clock.Held = false;
+        clock.Next(0);
+        Assert.Equal(1, clock.Frame);
+    }
+
+    // Published FNV-1a 64 vectors (isthe.com/chongo/tech/comp/fnv).
+    [Theory]
+    [InlineData("", 0xcbf29ce484222325UL)]
+    [InlineData("a", 0xaf63dc4c8601ec8cUL)]
+    [InlineData("foobar", 0x85944171f73967e8UL)]
+    public void Digest_FnvVectors(string text, ulong expected)
+    {
+        var d = new StateDigest();
+        d.Add(text);
+        Assert.Equal(expected, d.Value);
+        Assert.Equal(expected, StateDigest.Of(System.Text.Encoding.UTF8.GetBytes(text)));
+    }
+
+    // Hand-checked: FNV-1a 64 of the little-endian bytes 01 00 00 00 and of 1.5 as an IEEE double.
+    [Fact]
+    public void Digest_NumbersLittleEndian()
+    {
+        var u = new StateDigest();
+        u.Add(1u);
+        Assert.Equal(0xad2aca7747985764UL, u.Value);
+        var d = new StateDigest();
+        d.Add(1.5);
+        Assert.Equal(0xaa95e93229a27c80UL, d.Value);
+        Assert.Equal("aa95e93229a27c80", d.Hex);
+    }
+
+    [Fact]
+    public void Line_Format() =>
+        Assert.Equal("digest 120 3.5 000000000000beef", DigestLine.Format(120, 3.5, 0xbeef));
+
+    [Fact]
+    public void Line_FormatRoundsGameTime() =>
+        Assert.Equal("digest 1 0.017 0000000000000001", DigestLine.Format(1, 1.0 / 60, 1));
+
+    [Fact]
+    public void Line_Due()
+    {
+        Assert.True(DigestLine.Due(60, 60));
+        Assert.False(DigestLine.Due(59, 60));
+        Assert.False(DigestLine.Due(0, 60));
+        Assert.False(DigestLine.Due(60, 0));
+    }
+
+    // SplitMix64 seeded 0: outputs e220a8397b1dcdaf, 6e789e6aa1b965f4 (published reference sequence).
+    [Fact]
+    public void Seeds_SplitMixReference()
+    {
+        Assert.Equal(0xe220a8397b1dcdafUL, SeedStreams.Of(0, 0));
+        Assert.Equal(0x6e789e6aa1b965f4UL, SeedStreams.Of(0, 1));
+        Assert.Equal(0x63cbe1e459320dd7UL, SeedStreams.Of(7, 0));
+    }
+
+    [Fact]
+    public void Loop_StopsWhenFrameReturnsFalse()
+    {
+        var seen = new List<long>();
+        var (frames, capped) = HeadlessLoop.Run(n => { seen.Add(n); return n < 3; }, null);
+        Assert.Equal([1L, 2, 3], seen);
+        Assert.Equal(3, frames);
+        Assert.False(capped);
+    }
+
+    [Fact]
+    public void Loop_FramesLimit() => Assert.Equal((5L, false), HeadlessLoop.Run(_ => true, 5));
+
+    [Fact]
+    public void Loop_Cap() => Assert.Equal((10L, true), HeadlessLoop.Run(_ => true, null, cap: 10));
+}