UI Selenium tests on Azure Devops 2019 - azure-devops

Question

What is the correct way to run automated UI tests by a self-hosted agent?
I tried to add a tests step in the release pipeline but it's not working because the agent cannot find the DLLs with tests (they are in a few separate projects)
##[warning]No test assemblies found matching the pattern: **\Test.UI.dll,!**\*TestAdapter.dll,!**\obj\**.
Currently, the release pipeline is simple: one artifact from the build pipeline and one stage with the following steps:
1. IIS Web App Deploy
2. IIS Web App Manage
3. VsTest: tests are selected using Test assemblies option

Answer 1

No test assemblies found matching the pattern.
It seems that the .dll files don't exist in the artifact or under the path of the release agent. You may need to share more information about the Pipeline. (e.g. build agent, pipeline definition and vstest task definition)
Before this, you can refer to the following steps for troubleshooting.
First of all, you need to make sure that the .dll files exist in the build artifacts.
You could check this in Build Summary -> Artifacts. You could download it and check the files in the artifact.
If the files don't exist, you could add a Copy files task before the Publish Artifacts task.
For example:
- task: CopyFiles#2
displayName: 'Copy Files to: $(build.artifactstagingdirectory)'
inputs:
SourceFolder: '$(agent.builddirectory)'
TargetFolder: '$(build.artifactstagingdirectory)'
enabled: false
Then the "VsTest" task will find the files in $(System.DefaultWorkingDirectory) by default(No customization). In release pipeline, the path is equals to C:\agent\_work\rx\a (e.g. C:\agent\_work\r1\a)
Since you are using the self-hosted agent , you could directly check the files in the target path on your local machine.
If you couldn't find the target files, you may need to modify the search folder or Test files path.
You also could check the file path in the Release Pipeline log -> Download Artifacts Step.