How to pass the secret from azure key vault to Environmental variable

The environmental variable TEST_SECRETS shall contain the secrets from the azure key vault. This can be achieved by the AzureKeyVault task shown as follow

- task: AzureKeyVault@2
          displayName: Credential Fetch
          inputs:
            connectedServiceName: 'KVfetch'
            KeyVaultName: 'kv_abc_devops'
            SecretsFilter: 'db-primarykey-dev'
            RunAsPreJob: true

How can I pass the value of db-primarykey-dev to TEST_SECRETS

can I use variables as follows?

variables:
- name: TEST_SECRET
  value: $db-primarykey-dev

I try to pass the variable right before the test it does not work

- task: CmdLine@2
          displayName: Integration Tests
        - script: |
            echo 'TEST_SECRET = $db-primarykey-dev'
            pytest test/integration --verbose -s

You can do this using env mapping:

- task: CmdLine@2
  displayName: Integration Tests
- script: |
    pytest test/integration --verbose -s
  env:
    TEST_SECRET: $(db-primarykey-dev)

Also please check and try by specifying the azureSubscription field under inputs of azurekeyvault task if it makes difference byreplacing Connected service name or by including as additional parameter:

azureSubscription: 'YOUR SUBSCRIPTION HERE'  

Try with > echo $(TEST_SECRET) . See this doc for reference. See if you are missing inputs tag in

- task: CmdLine@2 
  displayName: Integration Tests
     inputs: 
        script: echo $(TEST_SECRET) 

See the reference. Also we can do environment mapping as said by @Krzysztof Madej