Add test for Template.

Author: pawchen

converter/tests/TemplateTests.cs

@@ -0,0 +1,17 @@
+using OriginLab.DocumentGeneration.Templates;
+
+namespace OriginLab.DocumentGeneration.Tests;
+
+public class TemplateTests
+{
+    [Theory]
+    [InlineData("de")]
+    [InlineData("ja")]
+    [InlineData("zh")]
+    public async Task NoEntitiesInThe404PageTitles(string language)
+    {
+        var html = await Template.Render404PageAsync(language);
+
+        Assert.Matches(@"<title>[^&#]*?</title>", html);
+    }
+}