Make dotnet-watch tests TFM agnostic (dotnet#44604)

Author: am11

test/dotnet-watch.Tests/HotReload/ApplyDeltaTests.cs

@@ -127,8 +127,8 @@ class AppUpdateHandler
 
             await App.AssertOutputLineStartsWith("Updated");
 
-            AssertEx.Contains(
-                "dotnet watch ⚠ [WatchHotReloadApp (net9.0)] Expected to find a static method 'ClearCache' or 'UpdateApplication' on type 'AppUpdateHandler, WatchHotReloadApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' but neither exists.",
+            AssertEx.ContainsRegex(
+                @"dotnet watch ⚠ \[WatchHotReloadApp \(net\d+\.\d+\)\] Expected to find a static method 'ClearCache' or 'UpdateApplication' on type 'AppUpdateHandler, WatchHotReloadApp, Version=1\.0\.0\.0, Culture=neutral, PublicKeyToken=null' but neither exists.",
                 App.Process.Output);
         }
 
@@ -168,13 +168,13 @@ class AppUpdateHandler
 
             await App.AssertOutputLineStartsWith("Updated");
 
-            AssertEx.Contains(
-                "dotnet watch ⚠ [WatchHotReloadApp (net9.0)] Exception from 'System.Action`1[System.Type[]]': System.InvalidOperationException: Bug!",
+            AssertEx.ContainsRegex(
+                @"dotnet watch ⚠ \[WatchHotReloadApp \(net\d+\.\d+\)\] Exception from 'System.Action`1\[System.Type\[\]\]': System.InvalidOperationException: Bug!",
                 App.Process.Output);
 
             if (verbose)
             {
-                AssertEx.Contains("dotnet watch 🕵️ [WatchHotReloadApp (net9.0)] Deltas applied.", App.Process.Output);
+                AssertEx.ContainsRegex(@"dotnet watch 🕵️ \[WatchHotReloadApp \(net\d+\.\d+\)\] Deltas applied.", App.Process.Output);
             }
             else
             {

test/dotnet-watch.Tests/Utilities/AssertEx.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections;
+using System.Text.RegularExpressions;
 using Xunit.Sdk;
 
 namespace Microsoft.DotNet.Watcher.Tools
@@ -241,6 +242,26 @@ public static void Contains(string expected, IEnumerable<string> items)
             Fail(message.ToString());
         }
 
+        public static void ContainsRegex(string pattern, IEnumerable<string> items)
+        {
+            var regex = new Regex(pattern, RegexOptions.Compiled);
+
+            if (items.Any(item => regex.IsMatch(item)))
+            {
+                return;
+            }
+
+            var message = new StringBuilder();
+            message.AppendLine($"Pattern '{pattern}' not found in:");
+
+            foreach (var item in items)
+            {
+                message.AppendLine($"'{item}'");
+            }
+
+            Fail(message.ToString());
+        }
+
         public static void DoesNotContain(string expected, IEnumerable<string> items)
             => Assert.DoesNotContain(expected, items);
     }