Azure devops pipeline gives error while importing python test modules

I am trying to run python unit tests in the azure DevOps pipeline using pytest, but it's giving the error below

here is the yml code

trigger:
- main
- test-unit-test-devops 

jobs:
  - job: Test
    pool:
      name: OnPrem   //private pool
      demands:
      - Agent.OS -equals Linux

    steps: 
    - task: UsePythonVersion@0
      inputs:
        versionSpec: '3.9.5'
        addToPath: true
        architecture: 'x64'
    
    - task: Bash@3
      inputs:
        targetType: 'inline'
        script: |
          python -m pip install --upgrade pip
          pip install -r requirements.txt
        workingDirectory: '$(Build.SourcesDirectory)'
      displayName: "Installing Dependencies"
        
    - task: Bash@3
      inputs:
        targetType: 'inline'
        script: pytest
        workingDirectory: '$(Build.SourcesDirectory)'
      displayName: "Run all unit tests"

the pipeline is passing all the above tasks except the "Run all unit tests" task, my folder structure is this

<project_root>/
 | - .venv/
 | - .vscode/
 | - add_pipeline_config/
 | | - __init__.py
 | | - function.json
 | | - example.py
 | - my_second_function/
 | | - __init__.py
 | | - function.json
 | - tests/
 | | - test_add_pipeline_config.py
 | - .funcignore
 | - host.json
 | - local.settings.json
 | - requirements.txt
 | - Dockerfile

I did try the following fixes but the error still persists

• Added/Removed init.py from the tests folder
• tried these scripts to run the test
  • pytest
  • python -m pytest
  • python -m pytest/pytest
• setting PYTHONPATH to $(Build.SourcesDirectory)
• creating & activating python virtualenv

I have also checked source dir by printing the $(Build.SourcesDirectory) which is /azp/_work/1/s and i can see my files inside this directory

Note: The error doesn't occur on my local machine. The error occurs only on azure devops

Could someone point out what am I doing wrong...would really appreciate