Feature-flagged support for JobContext.CheckRunId (#3811)

src/Test/L0/Worker/JobContextL0.cs

@@ -0,0 +1,38 @@
+using System;
+using GitHub.DistributedTask.Pipelines.ContextData;
+using GitHub.Runner.Worker;
+using Xunit;
+
+namespace GitHub.Runner.Common.Tests.Worker
+{
+    public class JobContextL0
+    {
+        [Fact]
+        public void CheckRunId_SetAndGet_WorksCorrectly()
+        {
+            var ctx = new JobContext();
+            ctx.CheckRunId = 12345;
+            Assert.Equal(12345, ctx.CheckRunId);
+            Assert.True(ctx.TryGetValue("check_run_id", out var value));
+            Assert.IsType<NumberContextData>(value);
+            Assert.Equal(12345, ((NumberContextData)value).Value);
+        }
+
+        [Fact]
+        public void CheckRunId_NotSet_ReturnsNull()
+        {
+            var ctx = new JobContext();
+            Assert.Null(ctx.CheckRunId);
+            Assert.False(ctx.TryGetValue("check_run_id", out var value));
+        }
+
+        [Fact]
+        public void CheckRunId_SetNull_RemovesKey()
+        {
+            var ctx = new JobContext();
+            ctx.CheckRunId = 12345;
+            ctx.CheckRunId = null;
+            Assert.Null(ctx.CheckRunId);
+        }
+    }
+}