Don't create multiple large files at the same time

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllBytes.cs

@@ -57,36 +57,6 @@ public void ValidWrite(int size)
             File.Delete(path);
         }
 
-        [Fact]
-        [OuterLoop]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/45954", TestPlatforms.Browser)]
-        public void ReadFileOver2GB()
-        {
-            string path = GetTestFilePath();
-            using (FileStream fs = File.Create(path))
-            {
-                fs.SetLength(int.MaxValue + 1L);
-            }
-
-            // File is too large for ReadAllBytes at once
-            Assert.Throws<IOException>(() => File.ReadAllBytes(path));
-        }
-
-        [Fact]
-        [OuterLoop]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/45954", TestPlatforms.Browser)]
-        public void ReadFileOverMaxArrayLength()
-        {
-            string path = GetTestFilePath();
-            using (FileStream fs = File.Create(path))
-            {
-                fs.SetLength(Array.MaxLength + 1L);
-            }
-
-            // File is too large for ReadAllBytes at once
-            Assert.Throws<IOException>(() => File.ReadAllBytes(path));
-        }
-
         [Fact]
         public void Overwrite()
         {

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllBytesAsync.cs

@@ -6,7 +6,6 @@
 using System.Threading.Tasks;
 using Xunit;
 using System.IO.Pipes;
-using Microsoft.DotNet.XUnitExtensions;
 
 namespace System.IO.Tests
 {
@@ -70,36 +69,6 @@ public Task AlreadyCanceledAsync()
                 async () => await File.WriteAllBytesAsync(path, new byte[0], token));
         }
 
-        [Fact]
-        [OuterLoop]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/45954", TestPlatforms.Browser)]
-        public async Task ReadFileOver2GBAsync()
-        {
-            string path = GetTestFilePath();
-            using (FileStream fs = File.Create(path))
-            {
-                fs.SetLength(int.MaxValue + 1L);
-            }
-
-            // File is too large for ReadAllBytesAsync at once
-            await Assert.ThrowsAsync<IOException>(async () => await File.ReadAllBytesAsync(path));
-        }
-
-        [Fact]
-        [OuterLoop]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/45954", TestPlatforms.Browser)]
-        public async Task ReadFileOverMaxArrayLengthAsync()
-        {
-            string path = GetTestFilePath();
-            using (FileStream fs = File.Create(path))
-            {
-                fs.SetLength(Array.MaxLength + 1L);
-            }
-
-            // File is too large for ReadAllBytesAsync at once
-            await Assert.ThrowsAsync<IOException>(async () => await File.ReadAllBytesAsync(path));
-        }
-
         [Fact]
         public async Task OverwriteAsync()
         {

src/libraries/System.IO.FileSystem/tests/FileStream/Read.cs

@@ -14,39 +14,5 @@ public void NegativeReadRootThrows()
             Assert.Throws<UnauthorizedAccessException>(() =>
                 new FileStream(Path.GetPathRoot(Directory.GetCurrentDirectory()), FileMode.Open, FileAccess.Read));
         }
-
-        [Fact]
-        [OuterLoop]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/45954", TestPlatforms.Browser)]
-        public void NoInt32OverflowInTheBufferingLogic()
-        {
-            const long position1 = 10;
-            const long position2 = (1L << 32) + position1;
-
-            string filePath = GetTestFilePath();
-            byte[] data1 = new byte[] { 1, 2, 3, 4, 5 };
-            byte[] data2 = new byte[] { 6, 7, 8, 9, 10 };
-            byte[] buffer = new byte[5];
-
-            using (var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write))
-            {
-                stream.Seek(position1, SeekOrigin.Begin);
-                stream.Write(data1);
-
-                stream.Seek(position2, SeekOrigin.Begin);
-                stream.Write(data2);
-            }
-
-            using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
-            {
-                stream.Seek(position1, SeekOrigin.Begin);
-                Assert.Equal(buffer.Length, stream.Read(buffer));
-                Assert.Equal(data1, buffer);
-
-                stream.Seek(position2, SeekOrigin.Begin);
-                Assert.Equal(buffer.Length, stream.Read(buffer));
-                Assert.Equal(data2, buffer);
-            }
-        }
     }
 }

src/libraries/System.IO.FileSystem/tests/LargeFileTests.cs

@@ -0,0 +1,99 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.IO.Tests;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace System.IO.FileSystem.Tests
+{
+    [OuterLoop]
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/45954", TestPlatforms.Browser)]
+    [Collection(nameof(DisableParallelization))] // don't create multiple large files at the same time
+    public class LargeFileTests : FileSystemTest
+    {
+        [Fact]
+        public void ReadFileOver2GB()
+        {
+            string path = GetTestFilePath();
+            using (FileStream fs = File.Create(path))
+            {
+                fs.SetLength(int.MaxValue + 1L);
+            }
+
+            // File is too large for ReadAllBytes at once
+            Assert.Throws<IOException>(() => File.ReadAllBytes(path));
+        }
+
+        [Fact]
+        public void ReadFileOverMaxArrayLength()
+        {
+            string path = GetTestFilePath();
+            using (FileStream fs = File.Create(path))
+            {
+                fs.SetLength(Array.MaxLength + 1L);
+            }
+
+            // File is too large for ReadAllBytes at once
+            Assert.Throws<IOException>(() => File.ReadAllBytes(path));
+        }
+
+        [Fact]
+        public async Task ReadFileOver2GBAsync()
+        {
+            string path = GetTestFilePath();
+            using (FileStream fs = File.Create(path))
+            {
+                fs.SetLength(int.MaxValue + 1L);
+            }
+
+            // File is too large for ReadAllBytesAsync at once
+            await Assert.ThrowsAsync<IOException>(async () => await File.ReadAllBytesAsync(path));
+        }
+
+        [Fact]
+        public async Task ReadFileOverMaxArrayLengthAsync()
+        {
+            string path = GetTestFilePath();
+            using (FileStream fs = File.Create(path))
+            {
+                fs.SetLength(Array.MaxLength + 1L);
+            }
+
+            // File is too large for ReadAllBytesAsync at once
+            await Assert.ThrowsAsync<IOException>(async () => await File.ReadAllBytesAsync(path));
+        }
+
+        [Fact]
+        public void NoInt32OverflowInTheBufferingLogic()
+        {
+            const long position1 = 10;
+            const long position2 = (1L << 32) + position1;
+
+            string filePath = GetTestFilePath();
+            byte[] data1 = new byte[] { 1, 2, 3, 4, 5 };
+            byte[] data2 = new byte[] { 6, 7, 8, 9, 10 };
+            byte[] buffer = new byte[5];
+
+            using (var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write))
+            {
+                stream.Seek(position1, SeekOrigin.Begin);
+                stream.Write(data1);
+
+                stream.Seek(position2, SeekOrigin.Begin);
+                stream.Write(data2);
+            }
+
+            using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
+            {
+                stream.Seek(position1, SeekOrigin.Begin);
+                Assert.Equal(buffer.Length, stream.Read(buffer));
+                Assert.Equal(data1, buffer);
+
+                stream.Seek(position2, SeekOrigin.Begin);
+                Assert.Equal(buffer.Length, stream.Read(buffer));
+                Assert.Equal(data2, buffer);
+            }
+        }
+    }
+}

src/libraries/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj

@@ -56,6 +56,7 @@
     <Compile Include="Enumeration\ExampleTests.cs" />
     <Compile Include="Enumeration\RemovedDirectoryTests.cs" />
     <Compile Include="Enumeration\SymbolicLinksTests.cs" />
+    <Compile Include="LargeFileTests.cs" />
     <Compile Include="PathInternalTests.cs" />
     <Compile Include="RandomAccess\Base.cs" />
     <Compile Include="RandomAccess\GetLength.cs" />