Use Path.Join instead of Path.Combine (#13090)

It is faster, and more predictable. Most changes are in test code.

Tweak behavior in AssemblyNamesTypeResolutionService to use API based
program files and add separator for proper contains checking. No need to
use both paths, it will always be current process specific.
###### Microsoft Reviewers: [Open in
CodeFlow](https://microsoft.github.io/open-pr/?codeflow=https://github.com/dotnet/winforms/pull/13090)

Author: JeremyKuhne

src/Common/tests/TestUtilities/FileCleanupTestBase.cs

@@ -16,7 +16,7 @@ public string TestDirectory
         {
             if (_testDirectory is null)
             {
-                _testDirectory = Path.Combine(Path.GetTempPath(), GetUniqueName());
+                _testDirectory = Path.Join(Path.GetTempPath(), GetUniqueName());
                 Directory.CreateDirectory(_testDirectory);
             }
 
@@ -43,7 +43,7 @@ protected virtual void Dispose(bool disposing)
         }
     }
 
-    public string GetTestFilePath() => Path.Combine(TestDirectory, GetTestFileName());
+    public string GetTestFilePath() => Path.Join(TestDirectory, GetTestFileName());
 
     public static string GetTestFileName() => GetUniqueName();
 

src/Common/tests/TestUtilities/TempFile.cs

@@ -81,6 +81,6 @@ private void DeleteFile()
     private static string GetFilePath(string? memberName, int lineNumber)
     {
         string file = $"{IO.Path.GetRandomFileName()}_{memberName}_{lineNumber}";
-        return IO.Path.Combine(IO.Path.GetTempPath(), file);
+        return IO.Path.Join(IO.Path.GetTempPath(), file);
     }
 }

src/Microsoft.VisualBasic.Forms/src/Microsoft/VisualBasic/Logging/FileLogTraceListener.vb

@@ -166,7 +166,7 @@ Namespace Microsoft.VisualBasic.Logging
                         Debug.Fail("Unrecognized LogFileCreationSchedule")
                 End Select
 
-                Return Path.Combine(basePath, fileName)
+                Return Path.Join(basePath, fileName)
             End Get
         End Property
 

src/Microsoft.VisualBasic.Forms/tests/UnitTests/System/Windows/Forms/FileLogTraceListenerTests.vb

@@ -45,7 +45,7 @@ Namespace Microsoft.VisualBasic.Forms.Tests
                         listener.DiskSpaceExhaustedBehavior = DiskSpaceExhaustedOption.ThrowException
                         listener.DiskSpaceExhaustedBehavior.Should.Be(DiskSpaceExhaustedOption.ThrowException)
 
-                        listener.FullLogFileName.Should.BeEquivalentTo(Path.Combine(testDirectory, $"{expectedBaseFileName}.log"))
+                        listener.FullLogFileName.Should.BeEquivalentTo(Path.Join(testDirectory, $"{expectedBaseFileName}.log"))
 
                         listener.LogFileCreationSchedule.Should.Be(LogFileCreationScheduleOption.None)
                         listener.LogFileCreationSchedule = LogFileCreationScheduleOption.Daily

src/Microsoft.VisualBasic.Forms/tests/UnitTests/System/Windows/Forms/VbFileCleanupTestBaseTests.vb

@@ -32,7 +32,7 @@ Namespace Microsoft.VisualBasic.Forms.Tests
 
         <WinFormsFact>
         Public Sub DirectoryIsAccessibleWithNonexistentPath()
-            Dim directoryPath As String = Path.Combine(CreateTempDirectory(), GetUniqueFileName)
+            Dim directoryPath As String = Path.Join(CreateTempDirectory(), GetUniqueFileName)
             DirectoryIsAccessible(directoryPath).Should.BeFalse()
         End Sub
 

src/Microsoft.VisualBasic.Forms/tests/UnitTests/System/Windows/TestUtilities/VbFileCleanupTestBase.vb

@@ -9,7 +9,7 @@ Namespace Microsoft.VisualBasic.Forms.Tests
     Public MustInherit Class VbFileCleanupTestBase
         Implements IDisposable
 
-        Private Shared ReadOnly s_baseTempPath As String = Path.Combine(Path.GetTempPath, "DownLoadTest9d9e3a8-7a46-4333-a0eb-4faf76994801")
+        Private Shared ReadOnly s_baseTempPath As String = Path.Join(Path.GetTempPath, "DownLoadTest9d9e3a8-7a46-4333-a0eb-4faf76994801")
         Friend Const DefaultFileName As String = "Testing.Txt"
         Friend ReadOnly _testDirectories As New HashSet(Of String)
 
@@ -46,7 +46,7 @@ Namespace Microsoft.VisualBasic.Forms.Tests
         '''  If size = -1 no file is create but the full path is returned.
         ''' </returns>
         Friend Shared Function CreateTempFile(sourceDirectoryName As String, Optional filename As String = DefaultFileName, Optional size As Integer = -1) As String
-            Dim filenameWithPath As String = Path.Combine(sourceDirectoryName, filename)
+            Dim filenameWithPath As String = Path.Join(sourceDirectoryName, filename)
 
             If size >= 0 Then
                 Using destinationStream As FileStream = File.Create(filenameWithPath)
@@ -68,7 +68,7 @@ Namespace Microsoft.VisualBasic.Forms.Tests
                 If Not info.Exists Then
                     Return False
                 End If
-                Dim path As String = IO.Path.Combine(directoryPath, GetUniqueFileName())
+                Dim path As String = IO.Path.Join(directoryPath, GetUniqueFileName())
                 Using stream As FileStream = File.Create(path)
                     stream.Close()
                 End Using
@@ -82,7 +82,7 @@ Namespace Microsoft.VisualBasic.Forms.Tests
         End Function
 
         Friend Shared Function GetUniqueFileNameWithPath(testDirectory As String) As String
-            Return Path.Combine(testDirectory, GetUniqueFileName())
+            Return Path.Join(testDirectory, GetUniqueFileName())
         End Function
 
         ''' <summary>
@@ -96,9 +96,9 @@ Namespace Microsoft.VisualBasic.Forms.Tests
         Friend Function CreateTempDirectory(<CallerMemberName> Optional memberName As String = Nothing, Optional lineNumber As Integer = -1) As String
             Dim folder As String
             If lineNumber > 0 Then
-                folder = Path.Combine(BaseTempPath, $"{memberName}{lineNumber}")
+                folder = Path.Join(BaseTempPath, $"{memberName}{lineNumber}")
             Else
-                folder = Path.Combine(BaseTempPath, memberName)
+                folder = Path.Join(BaseTempPath, memberName)
             End If
 
             If _testDirectories.Add(folder) Then

src/Microsoft.VisualBasic/tests/IntegrationTests/Microsoft.VisualBasic.IntegrationTests/InteractionTests.cs

@@ -104,7 +104,7 @@ public void Shell_ArgumentNullException()
     [Fact]
     public void Shell_FileNotFoundException()
     {
-        string path = Path.Combine(Path.GetTempPath(), GetUniqueName());
+        string path = Path.Join(Path.GetTempPath(), GetUniqueName());
         // Exception.ToString() called to verify message is constructed successfully.
         _ = Assert.Throws<FileNotFoundException>(() => Interaction.Shell(path)).ToString();
     }

src/Microsoft.VisualBasic/tests/UnitTests/Microsoft/VisualBasic/Devices/AudioTests.cs

@@ -49,7 +49,7 @@ public void PlayEmptyFileNameAudioMode_Throws(string fileName)
     [InvalidEnumData<AudioPlayMode>]
     public void PlayModeInvalid_Throws(AudioPlayMode audioPlayMode)
     {
-        string location = Path.Combine(Path.GetTempPath(), GetUniqueName());
+        string location = Path.Join(Path.GetTempPath(), GetUniqueName());
         Audio audio = new();
         Action testCode = () => audio.Play(location, audioPlayMode);
         testCode.Should().Throw<InvalidEnumArgumentException>();