通过调用Get Test Result Attachments REST API，我们可以获取所有附件的ID：

GET https://dev.azure.com/{organization}/{project}/_apis/test/Runs/{runId}/Results/{testCaseResultId}/attachments?api-version=6.0-preview.1

之后，如果你想获取附件，你可以用特定的Attachment ID调用Attachments - Get Test Result Attachment Zip REST API。

GET https://dev.azure.com/{organization}/{project}/_apis/test/Runs/{runId}/Results/{testCaseResultId}/attachments/{attachmentId}?api-version=6.0-preview.1

请注意，REST API Attachments - Get Test Result Attachment Zip将显示附件的上下文，而不是直接下载附件。如果您想下载附件，可以编写一个脚本将它们保存到本地目录。以下PowerShell脚本供您参考：

$AttachmentsOutfile = "D:\Test\HellWorld.java"

$connectionToken="You PAT Here"

$base64AuthInfo= [System.Convert]::ToBase64String([System.Text.Encoding]::  
ASCII.GetBytes(":$($connectionToken)"))

$AuditLogURL = "https://dev.azure.com/{organization}/{project}/_apis/test/Runs/{runId}/Results/{testCaseResultId}/attachments/{attachmentId}?api-version=6.0-preview.1" 

$AuditInfo = Invoke-RestMethod -Uri $AuditLogURL -Headers @{authorization = "Basic $base64AuthInfo"} -Method Get –OutFile $AttachmentsOutfile

更新：

但是，API只能从测试运行UI中获取附件（通过单击Add attachment按钮进行附加）。
为了获取测试运行结果步骤和测试运行结果摘要的附件，我们可以调用Results - Get REST API，并添加参数detailsToInclude=iterations：

GET https://dev.azure.com/{organization}/{project}/_apis/test/Runs/{runId}/results/{testCaseResultId}?detailsToInclude=iterations&api-version=6.0

然后我们可以通过ID下载附件。下面的PowerShell脚本供大家循环下载参考：

Param(
   [string]$orgurl = "https://dev.azure.com/{org}",
   [string]$project = "Test0924",
   [string]$downloadlocation = "C:\temp\1025\",
   [string]$TestRunId = "1000294",
   [string]$ResultId = "100000",
   [string]$user = "",
   [string]$token = "PAT"
)
# Base64-encodes the Personal Access Token (PAT) appropriately
$base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $user,$token)))

#List test result and test step attachments: 
$testresultUrl = "$orgurl/$project/_apis/test/Runs/$TestRunId/Results/$($ResultId)?detailsToInclude=iterations&api-version=6.0" 
$attachments = (Invoke-RestMethod -Uri $testresultUrl -Method Get -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)}).iterationDetails.attachments

ForEach ($attachment in $attachments) {
#Get test result and step attachments:
$attachmentid = $attachment.id
$attachmentname = $attachment.name
$attachmenturl = "$orgurl/$project/_apis/test/Runs/$TestRunId/Results/$ResultId/attachments/$($attachmentid)?api-version=6.0"
Invoke-RestMethod -Uri $attachmenturl -Method Get -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)} -OutFile $downloadlocation\$attachmentname
}