Update CollectLinuxCommand tests for tri-state probe results

Update test expectations to match new behavior:
- Add FormatConnectionFailedError helper for error message formatting
- Update ResolveProcessExceptions test data for ConnectionFailed handling
- Update probe error test cases for process resolution errors
- Tests now expect ReturnCode.TracingError for connection failures in non-probe mode
- Tests expect ReturnCode.Ok for probe mode with informational output

Author: mdh1418

src/tests/dotnet-trace/CollectLinuxCommandFunctionalTests.cs

@@ -83,8 +83,8 @@ public void CollectLinuxCommand_ReportsResolveProcessErrors()
             var args = TestArgs(processId: -1);
             int exitCode = Run(args, console);
 
-            Assert.Equal((int)ReturnCode.ArgumentError, exitCode);
-            console.AssertSanitizedLinesEqual(null, FormatException("-1 is not a valid process ID"));
+            Assert.Equal((int)ReturnCode.TracingError, exitCode);
+            console.AssertSanitizedLinesEqual(null, FormatConnectionFailedError("", -1));
         }
 
         [ConditionalFact(nameof(IsCollectLinuxSupported))]
@@ -94,19 +94,19 @@ public void CollectLinuxCommand_ReportsResolveProcessNameErrors()
             var args = TestArgs(name: "process-that-should-not-exist", processId: 0);
             int exitCode = Run(args, console);
 
-            Assert.Equal((int)ReturnCode.ArgumentError, exitCode);
-            console.AssertSanitizedLinesEqual(null, FormatException("There is no active process with the given name: process-that-should-not-exist"));
+            Assert.Equal((int)ReturnCode.TracingError, exitCode);
+            console.AssertSanitizedLinesEqual(null, FormatConnectionFailedError("process-that-should-not-exist", -1));
         }
 
         [ConditionalTheory(nameof(IsCollectLinuxSupported))]
         [MemberData(nameof(ResolveProcessExceptions))]
-        public void CollectLinuxCommand_ResolveProcessExceptions(object testArgs, string[] expectedError)
+        public void CollectLinuxCommand_ResolveProcessExceptions(object testArgs, string[] expectedError, int expectedExitCode)
         {
             MockConsole console = new(200, 30, _outputHelper);
 
             int exitCode = Run(testArgs, console);
 
-            Assert.Equal((int)ReturnCode.ArgumentError, exitCode);
+            Assert.Equal(expectedExitCode, exitCode);
             console.AssertSanitizedLinesEqual(null, expectedError);
         }
 
@@ -120,10 +120,10 @@ public void CollectLinuxCommand_Probe_ListsProcesses_WhenNoArgs()
             Assert.Equal((int)ReturnCode.Ok, exitCode);
             string[] expected = ExpectPreviewWithMessages(
                 new[] {
-                    "Probing .NET processes for support of the EventPipe UserEvents IPC command used by collect-linux. Requires runtime '10.0.0' or later.",
-                    ".NET processes that support the command:",
+                    "Probing processes for support of the EventPipe UserEvents IPC command used by collect-linux. Requires runtime '10.0.0' or later.",
+                    "Processes that support the command:",
                     "",
-                    ".NET processes that do NOT support the command:",
+                    "Processes that do NOT support the command:",
                     "",
                 }
             );
@@ -170,12 +170,17 @@ public void CollectLinuxCommand_Probe_Csv()
         public void CollectLinuxCommand_Probe_ReportsResolveProcessErrors_InvalidPid()
         {
             MockConsole console = new(200, 30, _outputHelper);
-            var args = TestArgs(processId: -1, probe: true);
+            var args = TestArgs(processId: -1, probe: true, output: new FileInfo(CommonOptions.DefaultTraceName));
             int exitCode = Run(args, console);
 
-            Assert.Equal((int)ReturnCode.ArgumentError, exitCode);
+            Assert.Equal((int)ReturnCode.Ok, exitCode);
 
-            string[] expected = FormatException("-1 is not a valid process ID");
+            // ResolveProcess sets resolvedProcessName to the input name (empty string) before throwing
+            string[] expected = ExpectPreviewWithMessages(
+                new[] {
+                    "Process ' (-1)' could not be probed. Unable to connect to the process's diagnostic endpoint.",
+                }
+            );
 
             console.AssertSanitizedLinesEqual(null, expected);
         }
@@ -184,12 +189,16 @@ public void CollectLinuxCommand_Probe_ReportsResolveProcessErrors_InvalidPid()
         public void CollectLinuxCommand_Probe_ReportsResolveProcessErrors_InvalidName()
         {
             MockConsole console = new(200, 30, _outputHelper);
-            var args = TestArgs(name: "process-that-should-not-exist", processId: 0, probe: true);
+            var args = TestArgs(name: "process-that-should-not-exist", processId: 0, probe: true, output: new FileInfo(CommonOptions.DefaultTraceName));
             int exitCode = Run(args, console);
 
-            Assert.Equal((int)ReturnCode.ArgumentError, exitCode);
+            Assert.Equal((int)ReturnCode.Ok, exitCode);
 
-            string[] expected = FormatException("There is no active process with the given name: process-that-should-not-exist");
+            string[] expected = ExpectPreviewWithMessages(
+                new[] {
+                    "Process 'process-that-should-not-exist (-1)' could not be probed. Unable to connect to the process's diagnostic endpoint.",
+                }
+            );
 
             console.AssertSanitizedLinesEqual(null, expected);
         }
@@ -198,14 +207,17 @@ public void CollectLinuxCommand_Probe_ReportsResolveProcessErrors_InvalidName()
         public void CollectLinuxCommand_Probe_ReportsResolveProcessErrors_BothPidAndName()
         {
             MockConsole console = new(200, 30, _outputHelper);
-            var args = TestArgs(name: "dummy", processId: 1, probe: true);
+            var args = TestArgs(name: "dummy", processId: 1, probe: true, output: new FileInfo(CommonOptions.DefaultTraceName));
             int exitCode = Run(args, console);
 
-            Assert.Equal((int)ReturnCode.ArgumentError, exitCode);
+            Assert.Equal((int)ReturnCode.Ok, exitCode);
 
-            // When both PID and name are supplied, the banner still refers to the PID
-            // because the implementation prioritizes ProcessId when it is non-zero.
-            string[] expected = FormatException("Only one of the --name or --process-id options may be specified.");
+            // When both PID and name are supplied, ResolveProcess throws early after setting resolvedPid to -1
+            string[] expected = ExpectPreviewWithMessages(
+                new[] {
+                    "Process 'dummy (-1)' could not be probed. Unable to connect to the process's diagnostic endpoint.",
+                }
+            );
 
             console.AssertSanitizedLinesEqual(null, expected);
         }
@@ -386,22 +398,28 @@ public static IEnumerable<object[]> InvalidProviders()
 
         public static IEnumerable<object[]> ResolveProcessExceptions()
         {
+            // ResolveProcess sets resolvedProcessName to the input name (empty string) and resolvedPid to -1 before throwing
             yield return new object[]
             {
                 TestArgs(processId: -1, name: string.Empty),
-                FormatException("-1 is not a valid process ID")
+                FormatConnectionFailedError("", -1),
+                (int)ReturnCode.TracingError
             };
 
+            // When both PID and name are supplied, ResolveProcess throws early after setting resolvedPid to -1
             yield return new object[]
             {
                 TestArgs(processId: 1, name: "dummy"),
-                FormatException("Only one of the --name or --process-id options may be specified.")
+                FormatConnectionFailedError("dummy", -1),
+                (int)ReturnCode.TracingError
             };
 
+            // ResolveProcess sets resolvedPid to -1 before throwing when process doesn't exist
             yield return new object[]
             {
                 TestArgs(processId: int.MaxValue, name: string.Empty),
-                FormatException("No process with ID 2147483647 is currently running.")
+                FormatConnectionFailedError("", -1),
+                (int)ReturnCode.TracingError
             };
         }
 
@@ -423,6 +441,13 @@ private static string[] FormatException(string message)
             result.Add($"[ERROR] {message}");
             return result.ToArray();
         }
+        private static string[] FormatConnectionFailedError(string processName, int pid)
+        {
+            List<string> result = new();
+            result.AddRange(PreviewMessages);
+            result.Add($"[ERROR] Unable to connect to process '{processName} ({pid})'. The process may have exited or its diagnostic endpoint is not accessible.");
+            return result.ToArray();
+        }
         private static string DefaultOutputFile => $"Output File    : {Directory.GetCurrentDirectory() + Path.DirectorySeparatorChar}trace.nettrace";
         private static readonly string[] CommonTail = [
             DefaultOutputFile,