test: add unit tests for BrandLogoOptions to verify logo settings and defaults

Author: Shewart

tests/ShellDocs.Tests/BrandLogoOptionsTests.cs

@@ -0,0 +1,50 @@
+using ShellDocs.Components;
+using Xunit;
+
+namespace ShellDocs.Tests;
+
+public class BrandLogoOptionsTests
+{
+    [Fact]
+    public void SetLogo_SingleUrl_AppliesToBothThemes()
+    {
+        var options = new ShellDocsOptions().SetLogo("/img/logo.svg");
+
+        Assert.Equal("/img/logo.svg", options.LogoLight);
+        Assert.Equal("/img/logo.svg", options.LogoDark);
+    }
+
+    [Fact]
+    public void SetLogo_LightAndDark_KeepsBothDistinct()
+    {
+        var options = new ShellDocsOptions().SetLogo("/img/light.svg", "/img/dark.svg", "Brand");
+
+        Assert.Equal("/img/light.svg", options.LogoLight);
+        Assert.Equal("/img/dark.svg", options.LogoDark);
+        Assert.Equal("Brand", options.LogoAlt);
+    }
+
+    [Fact]
+    public void LogoHeight_DefaultsToOnePointThreeSevenFiveRem()
+    {
+        Assert.Equal(1.375, new ShellDocsOptions().LogoHeight);
+    }
+
+    [Fact]
+    public void Logos_DefaultToNull_SoDotFallbackRenders()
+    {
+        var options = new ShellDocsOptions();
+        Assert.Null(options.LogoLight);
+        Assert.Null(options.LogoDark);
+        Assert.Null(options.LogoSvg);
+    }
+
+    [Fact]
+    public void LogoSvg_HoldsRawMarkupUntouched()
+    {
+        const string svg = "<svg viewBox=\"0 0 24 24\"><path d=\"M0 0h24v24H0z\" fill=\"currentColor\"/></svg>";
+        var options = new ShellDocsOptions { LogoSvg = svg };
+
+        Assert.Equal(svg, options.LogoSvg);
+    }
+}