Steps to reproduce

Run the Test-Connection cmdlet specifying a buffer size of 0, then inspect the BufferSize property of the output PingStatus object, or check the returned table:

$result = Test-Connection -TargetName localhost -Count 1 -BufferSize 0
Write-Host "Result BufferSize property: $($result.BufferSize)"
Write-Host "Actual Reply.Buffer.Length: $($result.Reply.Buffer.Length)"

Expected behavior

The cmdlet output and the BufferSize property should correctly reflect the requested buffer size of 0:

Result BufferSize property: 0
Actual Reply.Buffer.Length: 0

Actual behavior

The cmdlet output and the BufferSize property incorrectly report 32:

Result BufferSize property: 32
Actual Reply.Buffer.Length: 0

The console output table also reports the BufferSize (B) as 32:

Ping Source           Address                   Latency BufferSize Status
                                                   (ms)        (B)
---- ------           -------                   ------- ---------- ------
   1 localhost        ::1                             0         32 Success

Error details

No exception is thrown. The ping completes successfully but outputs incorrect metadata.

Environment data

Name                           Value
----                           -----
PSVersion                      7.6.3
PSEdition                      Core
GitCommitId                    7.6.3
OS                             Microsoft Windows 10.0.26200
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion      2.4
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Additional Context

This is caused by the following logic in TestConnectionCommand.cs:

buffer.Length == 0 ? DefaultSendBufferSize : buffer.Length

When -BufferSize 0 is passed, GetSendBuffer(0) allocates a 0-length array (new byte[0]). Since buffer.Length is 0, the expression evaluates to DefaultSendBufferSize (32), misreporting the buffer size as 32 bytes even though a 0-byte payload was actually sent.