[wasm] Addressing System.Runtime.Extensions failures

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -1790,7 +1790,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Stopwatch.Unix.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\RuntimeEventSourceHelper.Unix.cs" Condition="'$(FeaturePerfTracing)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.NoRegistry.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\Environment.Unix.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Environment.UnixOrBrowser.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.OSVersion.OSX.cs" Condition="'$(IsOSXLike)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.OSVersion.Unix.cs" Condition="'$(IsOSXLike)' != 'true' and '$(TargetsBrowser)' != 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.GetFolderPathCore.Unix.cs" Condition="'$(TargetsiOS)' != 'true' and '$(TargetstvOS)' != 'true'" />
@@ -1818,8 +1818,11 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\TimerQueue.Unix.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\TimeZoneInfo.Unix.cs" />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetsUnix)' == 'true'">
+    <Compile Include="$(MSBuildThisFileDirectory)System\Environment.Unix.cs" />
+  </ItemGroup>
   <ItemGroup Condition="'$(TargetsBrowser)' == 'true'">
-    <Compile Include="$(MSBuildThisFileDirectory)System\Environment.OSVersion.Browser.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Environment.Browser.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(IsOSXLike)' == 'true'">
     <Compile Include="$(CommonPath)Interop\OSX\Interop.libobjc.cs">

src/libraries/System.Private.CoreLib/src/System/Environment.Browser.cs

@@ -0,0 +1,26 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System
+{
+    public static partial class Environment
+    {
+        // Emscripten VFS mounts at / and is the only drive
+        public static string[] GetLogicalDrives() => new string[] { "/" };
+
+        // In the mono runtime, this maps to gethostname, which returns 'emscripten'.
+        // Returning the value here allows us to exclude more of the runtime.
+        public static string MachineName => "localhost";
+
+        // Matching what we returned for an earlier release.  There isn't an established equivalent
+        // on wasm.
+        public static long WorkingSet => 0;
+
+        public static string UserName => "Browser";
+
+        private static OperatingSystem GetOSVersion()
+        {
+            return new OperatingSystem(PlatformID.Other, new Version(1, 0, 0, 0));
+        }
+    }
+}

src/libraries/System.Private.CoreLib/src/System/Environment.Unix.cs

@@ -12,44 +12,8 @@ namespace System
 {
     public static partial class Environment
     {
-        public static bool UserInteractive => true;
-
-        private static string CurrentDirectoryCore
-        {
-            get => Interop.Sys.GetCwd();
-            set => Interop.CheckIo(Interop.Sys.ChDir(value), value, isDirectory: true);
-        }
-
-        private static string ExpandEnvironmentVariablesCore(string name)
-        {
-            var result = new ValueStringBuilder(stackalloc char[128]);
-
-            int lastPos = 0, pos;
-            while (lastPos < name.Length && (pos = name.IndexOf('%', lastPos + 1)) >= 0)
-            {
-                if (name[lastPos] == '%')
-                {
-                    string key = name.Substring(lastPos + 1, pos - lastPos - 1);
-                    string? value = GetEnvironmentVariable(key);
-                    if (value != null)
-                    {
-                        result.Append(value);
-                        lastPos = pos + 1;
-                        continue;
-                    }
-                }
-                result.Append(name.AsSpan(lastPos, pos - lastPos));
-                lastPos = pos;
-            }
-            result.Append(name.AsSpan(lastPos));
-
-            return result.ToString();
-        }
-
         public static string[] GetLogicalDrives() => Interop.Sys.GetAllMountPoints();
 
-        private static bool Is64BitOperatingSystemWhen32BitProcess => false;
-
         public static string MachineName
         {
             get
@@ -60,13 +24,24 @@ public static string MachineName
             }
         }
 
-        private static int GetCurrentProcessId() => Interop.Sys.GetPid();
-
-        internal const string NewLineConst = "\n";
-
-        public static string SystemDirectory => GetFolderPathCore(SpecialFolder.System, SpecialFolderOption.None);
+        public static long WorkingSet
+        {
+            get
+            {
+                Type? processType = Type.GetType("System.Diagnostics.Process, System.Diagnostics.Process, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", throwOnError: false);
+                if (processType?.GetMethod("GetCurrentProcess")?.Invoke(null, BindingFlags.DoNotWrapExceptions, null, null, null) is IDisposable currentProcess)
+                {
+                    using (currentProcess)
+                    {
+                        if (processType!.GetMethod("get_WorkingSet64")?.Invoke(currentProcess, BindingFlags.DoNotWrapExceptions, null, null, null) is long result)
+                            return result;
+                    }
+                }
 
-        public static int SystemPageSize => CheckedSysConf(Interop.Sys.SysConfName._SC_PAGESIZE);
+                // Could not get the current working set.
+                return 0;
+            }
+        }
 
         public static unsafe string UserName
         {
@@ -135,40 +110,5 @@ private static unsafe bool TryGetUserNameFromPasswd(byte* buf, int bufLen, out s
             // Otherwise, fail.
             throw new IOException(errorInfo.GetErrorMessage(), errorInfo.RawErrno);
         }
-
-        public static string UserDomainName => MachineName;
-
-        /// <summary>Invoke <see cref="Interop.Sys.SysConf"/>, throwing if it fails.</summary>
-        private static int CheckedSysConf(Interop.Sys.SysConfName name)
-        {
-            long result = Interop.Sys.SysConf(name);
-            if (result == -1)
-            {
-                Interop.ErrorInfo errno = Interop.Sys.GetLastErrorInfo();
-                throw errno.Error == Interop.Error.EINVAL ?
-                    new ArgumentOutOfRangeException(nameof(name), name, errno.GetErrorMessage()) :
-                    Interop.GetIOException(errno);
-            }
-            return (int)result;
-        }
-
-        public static long WorkingSet
-        {
-            get
-            {
-                Type? processType = Type.GetType("System.Diagnostics.Process, System.Diagnostics.Process, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", throwOnError: false);
-                if (processType?.GetMethod("GetCurrentProcess")?.Invoke(null, BindingFlags.DoNotWrapExceptions, null, null, null) is IDisposable currentProcess)
-                {
-                    using (currentProcess)
-                    {
-                        if (processType!.GetMethod("get_WorkingSet64")?.Invoke(currentProcess, BindingFlags.DoNotWrapExceptions, null, null, null) is long result)
-                            return result;
-                    }
-                }
-
-                // Could not get the current working set.
-                return 0;
-            }
-        }
     }
 }

src/libraries/System.Private.CoreLib/src/System/Environment.UnixOrBrowser.cs

@@ -0,0 +1,75 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics;
+using System.IO;
+using System.Reflection;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading;
+
+namespace System
+{
+    public static partial class Environment
+    {
+        public static bool UserInteractive => true;
+
+        private static string CurrentDirectoryCore
+        {
+            get => Interop.Sys.GetCwd();
+            set => Interop.CheckIo(Interop.Sys.ChDir(value), value, isDirectory: true);
+        }
+
+        private static string ExpandEnvironmentVariablesCore(string name)
+        {
+            var result = new ValueStringBuilder(stackalloc char[128]);
+
+            int lastPos = 0, pos;
+            while (lastPos < name.Length && (pos = name.IndexOf('%', lastPos + 1)) >= 0)
+            {
+                if (name[lastPos] == '%')
+                {
+                    string key = name.Substring(lastPos + 1, pos - lastPos - 1);
+                    string? value = GetEnvironmentVariable(key);
+                    if (value != null)
+                    {
+                        result.Append(value);
+                        lastPos = pos + 1;
+                        continue;
+                    }
+                }
+                result.Append(name.AsSpan(lastPos, pos - lastPos));
+                lastPos = pos;
+            }
+            result.Append(name.AsSpan(lastPos));
+
+            return result.ToString();
+        }
+
+        private static bool Is64BitOperatingSystemWhen32BitProcess => false;
+
+        private static int GetCurrentProcessId() => Interop.Sys.GetPid();
+
+        internal const string NewLineConst = "\n";
+
+        public static string SystemDirectory => GetFolderPathCore(SpecialFolder.System, SpecialFolderOption.None);
+
+        public static int SystemPageSize => CheckedSysConf(Interop.Sys.SysConfName._SC_PAGESIZE);
+
+        public static string UserDomainName => MachineName;
+
+        /// <summary>Invoke <see cref="Interop.Sys.SysConf"/>, throwing if it fails.</summary>
+        private static int CheckedSysConf(Interop.Sys.SysConfName name)
+        {
+            long result = Interop.Sys.SysConf(name);
+            if (result == -1)
+            {
+                Interop.ErrorInfo errno = Interop.Sys.GetLastErrorInfo();
+                throw errno.Error == Interop.Error.EINVAL ?
+                    new ArgumentOutOfRangeException(nameof(name), name, errno.GetErrorMessage()) :
+                    Interop.GetIOException(errno);
+            }
+            return (int)result;
+        }
+    }
+}

src/libraries/System.Runtime.Extensions/tests/System/AppDomainTests.cs

@@ -44,6 +44,7 @@ public void RelativeSearchPath_Is_Null()
         }
 
         [Fact]
+        [PlatformSpecific(~TestPlatforms.Browser)] // throws pNSE
         public void TargetFrameworkTest()
         {
             const int ExpectedExitCode = 0;
@@ -129,7 +130,7 @@ public void FriendlyName()
 
             // GetEntryAssembly may be null (i.e. desktop)
             if (expected == null)
-                expected = Assembly.GetExecutingAssembly().GetName().Name;
+                expected = "DefaultDomain";
 
             Assert.Equal(expected, s);
         }
@@ -371,6 +372,7 @@ public void ReflectionOnlyGetAssemblies()
         }
 
         [Fact]
+        [PlatformSpecific(~TestPlatforms.Browser)] // Throws PNSE
         public void MonitoringIsEnabled()
         {
             Assert.True(AppDomain.MonitoringIsEnabled);

src/libraries/System.Runtime.Extensions/tests/System/Environment.Exit.cs

@@ -41,6 +41,7 @@ public static void ExitCode_Roundtrips(int exitCode)
         [InlineData(1)] // setting ExitCode and exiting Main
         [InlineData(2)] // setting ExitCode both from Main and from an Unloading event handler.
         [InlineData(3)] // using Exit(exitCode)
+        [PlatformSpecific(~TestPlatforms.Browser)] // throws PNSE
         public static void ExitCode_VoidMainAppReturnsSetValue(int mode)
         {
             int expectedExitCode = 123;

src/libraries/System.Runtime.Extensions/tests/System/Environment.MachineName.cs

@@ -20,6 +20,8 @@ internal static string GetComputerName()
 #if !Unix
                 return Environment.GetEnvironmentVariable("COMPUTERNAME");
 #else
+                if (PlatformDetection.IsBrowser)
+                    return "localhost";
                 string temp = Interop.Sys.GetNodeName();
                 int index = temp.IndexOf('.');
                 return index < 0 ? temp : temp.Substring(0, index);

src/libraries/System.Runtime.Extensions/tests/System/Environment.StackTrace.cs

@@ -68,6 +68,7 @@ public TestClass()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/38995", TestPlatforms.Browser)]
         public void StackTraceDoesNotStartWithInternalFrame()
         {
              string stackTrace = Environment.StackTrace;

src/libraries/System.Runtime.Extensions/tests/System/EnvironmentTests.cs

@@ -221,7 +221,10 @@ public void Version_Valid()
         [Fact]
         public void WorkingSet_Valid()
         {
-            Assert.True(Environment.WorkingSet > 0, "Expected positive WorkingSet value");
+            if (PlatformDetection.IsBrowser)
+                Assert.Equal(0, Environment.WorkingSet);
+            else
+                Assert.True(Environment.WorkingSet > 0, "Expected positive WorkingSet value");
         }
 
         [Trait(XunitConstants.Category, XunitConstants.IgnoreForCI)] // fail fast crashes the process

src/libraries/System.Runtime.Extensions/tests/System/IO/PathTests.cs

@@ -216,8 +216,6 @@ public static TheoryData<string, string> GetFullPath_BasicExpansions
                     { currentDirectory, currentDirectory },
                     // "." => current directory
                     { ".", currentDirectory },
-                    // ".." => up a directory
-                    { "..", Path.GetDirectoryName(currentDirectory) },
                     // "dir/./././." => "dir"
                     { Path.Combine(currentDirectory, ".", ".", ".", ".", "."), currentDirectory },
                     // "dir///." => "dir"
@@ -234,6 +232,12 @@ public static TheoryData<string, string> GetFullPath_BasicExpansions
                     { root + new string(Path.DirectorySeparatorChar, 3), root },
                 };
 
+                if (currentDirectory != Path.GetPathRoot(currentDirectory))
+                {
+                    // ".." => up a directory
+                    data.Add("..", Path.GetDirectoryName(currentDirectory));
+                }
+
                 // Path longer than MaxPath that normalizes down to less than MaxPath
                 const int Iters = 10000;
                 var longPath = new StringBuilder(currentDirectory, currentDirectory.Length + (Iters * 2));