Read the status line of a console run through StatusReport.Read [patch]

TrayApp.Test/ConsoleRunnerTests.cs

@@ -88,7 +88,7 @@ public void Run_WhenTheToolRefusesToStart_ExitsOneWithoutStopping()
 	}
 
 	[TestMethod]
-	public void Run_WhenTheRunItselfThrows_StillStops()
+	public void Run_WhenTheStatusThrows_ReportsItAndStillRunsAndStops()
 	{
 		bool stopped = false;
 
@@ -97,10 +97,26 @@ public void Run_WhenTheRunItselfThrows_StillStops()
 			.OnStop(() => stopped = true)
 			.Build();
 
-		// Describing the run is the tool's code too. Whatever it does, the release on the way out is the
-		// library's promise, so it happens in a finally rather than after the last statement.
-		Assert.ThrowsExactly<InvalidOperationException>(() => ConsoleRunner.Run(app, ShortRun()));
+		// Describing the run is the tool's code too, and a getter that throws is most likely to do so in the
+		// environment that sends a run here, so it is the line's text, as in --status, not an unhandled
+		// exception that breaks the exit-code contract.
+		using System.IO.StringWriter output = new();
+		System.IO.TextWriter original = Console.Out;
+		Console.SetOut(output);
+		int exitCode;
+		try
+		{
+			exitCode = ConsoleRunner.Run(app, ShortRun());
+		}
+		finally
+		{
+			Console.SetOut(original);
+		}
+
+		Assert.AreEqual(0, exitCode);
 		Assert.IsTrue(stopped);
+		Assert.Contains("demo: error: the status broke, stopping after", output.ToString());
+		Assert.Contains("demo: stopped.", output.ToString());
 	}
 
 	[TestMethod]

TrayApp/ConsoleRunner.cs

@@ -94,9 +94,14 @@ private static string DescribeRun(TrayAppDefinition app, CommandLineOptions opti
 			? string.Create(CultureInfo.InvariantCulture, $", stopping after {window:g}")
 			: string.Empty;
 
+		// The getter is the tool's code, and it is most likely to throw for the same reason the tool cannot
+		// work - a missing helper, say - which is also when the tray falls back to this mode. It is read the
+		// way --status reads it, so it becomes the line's text rather than an unhandled exception.
+		string state = app.Status is Func<string> status ? StatusReport.Read(status) : app.Describe();
+
 		return string.Create(
 			CultureInfo.InvariantCulture,
-			$"{app.Name}: {app.Describe()}{until}. Press Ctrl+C to stop.");
+			$"{app.Name}: {state}{until}. Press Ctrl+C to stop.");
 	}
 
 	/// <summary>