feat(vtag): passthrough fast-path skips Roslyn for mirror scripts (A)

2026-06-07 15:26:20 -04:00
parent 3834400f05
commit 08d7477860
5 changed files with 256 additions and 3 deletions
@@ -0,0 +1,79 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Scripting;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.Scripting.Tests;
+
+/// <summary>
+/// Unit tests for <see cref="PassthroughScript"/> — the Roslyn-free classifier that recognises
+/// the trivial mirror shape <c>return ctx.GetTag("X").Value;</c>. The pattern must be narrow:
+/// any near-miss (arithmetic, a different member, multi-statement, a different method) falls
+/// through so the Roslyn path stays authoritative.
+/// </summary>
+public sealed class PassthroughScriptTests
+{
+    /// <summary>The canonical mirror shape matches and captures the referenced tag.</summary>
+    [Fact]
+    public void Matches_canonical_mirror_and_captures_tag()
+    {
+        PassthroughScript.TryMatch("return ctx.GetTag(\"a\").Value;", out var tag).ShouldBeTrue();
+        tag.ShouldBe("a");
+    }
+
+    /// <summary>A dotted / hierarchical tag reference is captured verbatim.</summary>
+    [Fact]
+    public void Captures_dotted_tag_reference()
+    {
+        PassthroughScript.TryMatch("return ctx.GetTag(\"Area1.Machine.Speed\").Value;", out var tag)
+            .ShouldBeTrue();
+        tag.ShouldBe("Area1.Machine.Speed");
+    }
+
+    /// <summary>Whitespace around every token is tolerated.</summary>
+    [Fact]
+    public void Tolerates_surrounding_and_inner_whitespace()
+    {
+        PassthroughScript.TryMatch("  return  ctx . GetTag( \"a\" ) . Value ; ", out var tag)
+            .ShouldBeTrue();
+        tag.ShouldBe("a");
+    }
+
+    /// <summary>Arithmetic on the mirror value is NOT a passthrough.</summary>
+    [Fact]
+    public void Rejects_arithmetic_on_value()
+    {
+        PassthroughScript.TryMatch("return (int)ctx.GetTag(\"a\").Value + 1;", out _).ShouldBeFalse();
+    }
+
+    /// <summary>Reading a different member (StatusCode) is NOT a passthrough.</summary>
+    [Fact]
+    public void Rejects_other_member_access()
+    {
+        PassthroughScript.TryMatch("return ctx.GetTag(\"a\").StatusCode;", out _).ShouldBeFalse();
+    }
+
+    /// <summary>A multi-statement body is NOT a passthrough.</summary>
+    [Fact]
+    public void Rejects_multi_statement_body()
+    {
+        PassthroughScript.TryMatch("var x = ctx.GetTag(\"a\").Value; return x;", out _).ShouldBeFalse();
+    }
+
+    /// <summary>A different method name is NOT a passthrough.</summary>
+    [Fact]
+    public void Rejects_different_method()
+    {
+        PassthroughScript.TryMatch("return ctx.GetVirtualTag(\"a\").Value;", out _).ShouldBeFalse();
+    }
+
+    /// <summary>Null / empty / whitespace input is rejected.</summary>
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    public void Rejects_null_or_blank(string? source)
+    {
+        PassthroughScript.TryMatch(source, out var tag).ShouldBeFalse();
+        tag.ShouldBe(string.Empty);
+    }
+}