add: 头歌上的隐藏测试集 (#82)

Reviewed-on: PostGuard/Canon#82

Canon.Tests/SemanticTests/Tests.cs

@@ -0,0 +1,59 @@
+using Canon.Core.SemanticParser;
+using Canon.Core.SyntaxNodes;
+using Canon.Tests.Utils;
+using Xunit.Abstractions;
+
+namespace Canon.Tests.SemanticTests;
+
+public class Tests(ITestOutputHelper helper)
+{
+    [Fact]
+    public void Test()
+    {
+        const string program = """
+                               program main;
+
+                               var
+                               x, y: array[0..0] of integer;
+                               a, b: integer;
+
+                               function exgcd(a, b: integer; var x, y: integer): integer;
+                               var
+                               t, r: integer;
+                               begin
+                               if b = 0 then
+                               begin
+                               x := 1;
+                               y := 0;
+                               exgcd := a;
+                               end
+                               else
+                               begin
+                               r := exgcd(b, a mod b, x, y);
+                               t := x;
+                               x := y;
+                               y := (t - (a div b) * y);
+                               exgcd := r;
+                               end;
+                               end;
+
+                               begin
+                               a := 7;
+                               b := 15;
+                               x[0] := 1;
+                               y[0] := 1;
+                               exgcd(a, b, x[0], y[0]);
+                               x[0] := ((x[0] mod b) + b) mod b;
+                               write(x[0]);
+                               end.
+                               """;
+
+        ProgramStruct root = CompilerHelpers.Analyse(program);
+        SyntaxTreeTraveller traveller = new();
+
+        CodeGeneratorVisitor visitor = new();
+        traveller.Travel(root, visitor);
+
+        helper.WriteLine(visitor.Builder.Build());
+    }
+}