Fix: tedge connect c8y --test must not use a persistent MQTT session

[didier-wenzek]

By using a persistent session, tedge connect c8y --test might return false positive, telling the connection with c8y is okay, while the received tokens were simply stalled and persisted by mistake. => All MQTT connections used to retrieve JWT token must set the clean session flag to true.

To Reproduce

Start as for #2207, but on a device that is actively connected for a while and where tedge connect c8y --test. has not been run during this period.

1. Ensure that the used network interface is up.
2. Run the command tedge connect c8y.
3. Bring down the network interface sudo up link set wlan down or just disconnect your network cable.
4. Run the command tedge connect c8y --test.
5. Unexpectedly, the previous command tells everything is fine pretending that a token has just been received from c8y.

This token was simply persisted by mosquitto.

Simple way to reproduce the issue

tedge connect c8y --test must not be fooled by a token sent before the connection test.

1. Ensure that the used network interface is up.
2. Run the command tedge connect c8y.
3. Bring down the network interface sudo tp link set wlan down or just disconnect your network cable.
4. Publish a fake-token: tedge mqtt pub c8y/s/dat 71,fake-token --qos 1
5. Run the test: tedge connect c8y --test.
6. Issue: tedge connect wrongly tells the connection is up.
7. Expected behavior: tedge connect ignores the fake token and tells that the device is in unknown status

Proposed changes

Clear the session flag of the MQTT connection used by tedge connect c8y --test

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

#2207 (comment)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[codecov]

Codecov Report

Merging #2209 (7be4619) into main (c07cf47) will decrease coverage by 0.1%.
Report is 1 commits behind head on main.
The diff coverage is 33.3%.

Additional details and impacted files

Files Changed	Coverage Δ
crates/core/c8y_api/src/smartrest/error.rs	0.0% <ø> (ø)
crates/core/c8y_api/src/smartrest/operations.rs	81.5% <0.0%> (-0.5%)	⬇️
crates/core/tedge/src/cli/connect/command.rs	0.0% <0.0%> (ø)
crates/core/tedge/src/cli/mqtt/cli.rs	61.5% <ø> (-3.0%)	⬇️
...tes/core/tedge_agent/src/state_repository/error.rs	0.0% <ø> (ø)
plugins/tedge_apt_plugin/src/main.rs	26.0% <ø> (+0.6%)	⬆️
...tes/core/tedge_agent/src/state_repository/state.rs	86.8% <50.0%> (ø)
crates/extensions/c8y_mapper_ext/src/tests.rs	92.9% <100.0%> (-0.1%)	⬇️

... and 7 files with indirect coverage changes

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
261	0	5	261	100	47m36.193s

[gligorisaev]

QA has thoroughly checked the feature and here are the results:

• Test for ticket exists in the test suite.
• QA has tested the feature and it meets the required specifications.