examples: Add _helpers.py file to non-driver examples and update acceptance tests

[vigkre]

• This contribution adheres to CONTRIBUTING.md.

What does this Pull Request accomplish?

• Adds the common helpers file _helpers.py to the example measurements:
  • sample_measurement
  • sample_streaming_measurement
  • ui_progress_updates

Why should this Pull Request be merged?

• When customer tries to generate a measurement using template, they will be able to notice _helpers.py file generated, but when they refer the example measurements they might not see _helpers.py file.
• To overcome this confusion, driver examples (nidcpower, nidmm etc..,) are already updated with _helpers.py file to match template. Hence, updating the other examples to use _helpers.py
• Adds fake measurement_service (copied details from example measurements).
• Update tests to use fake measurement_service instead of running examples

What testing has been done?

• Updated the examples to use _helpers.py and Ran poetry run pytest to verify all tests passed.

[github-actions]

Test Results

     12 files  ±0       12 suites  ±0   17m 32s ⏱️ - 1m 14s
   180 tests ±0     180 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
2 148 runs  ±0  2 148 ✔️ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 54fe38e. ± Comparison against base commit ef7d247.

♻️ This comment has been updated with latest results.

[dixonjoel]

I could go either way on whether we should include these, but I have no strong objection to doing it. I'd wait for @bkeryan to chime in before submitting.

[bkeryan]

I could go either way on whether we should include these, but I have no strong objection to doing it. I'd wait for @bkeryan to chime in before submitting.

Updating these examples to use _helpers.py will break the tests. See #257

If you want to use _helpers.py in all the examples, you should update the tests to use their own services instead of running the examples.

[dixonjoel]

Updating these examples to use _helpers.py will break the tests. See #257

All the checks passed for this PR. Did you expect them to break? In what way does _helpers.py cause them to break?

[bkeryan]

Updating these examples to use _helpers.py will break the tests. See #257

All the checks passed for this PR. Did you expect them to break? In what way does _helpers.py cause them to break?

This PR doesn't update the examples to use _helpers.py. It just adds dead code.

If you update measurement.py to import _helpers, it will fail when you run the tests because there is no top-level _helpers module when you run the tests. If you update measurement.py to import helpers in a way that works in the tests, then it will fail when you run the measurement standalone. See #328 (comment) for more info.

[vigkre]

If you want to use _helpers.py in all the examples, you should update the tests to use their own services instead of running the examples.

@bkeryan I have added fake measurement_service (copied details from example measurements). Also, update acceptance tests to use fake measurement_service instead of running examples.