Ensure we always fire time pattern changes after microsecond 0

[bdraco]

2nd attempt at fixing #39012 (more desirable option)

Proposed change

Ensure we always fire time pattern changes after microsecond 0

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

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Additional information

• This PR fixes or closes issue: fixes #
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• The code change is tested and works locally.
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• Tests have been added to verify that the new code works.

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[bdraco]

Testing with this automation

- id: '1598489065877'
  alias: Time Pattern Test
  description: Time Pattern Test
  trigger:
  - platform: time_pattern
    hours: '*'
    minutes: '*'
    seconds: '*'
  condition: []
  action:
  - service: system_log.write
    data_template:
      level: error
      logger: homeassistant.components.mylogger
      message: 'The time is: {{ now() }}'
  mode: single

2020-08-27 00:52:10 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:10.002089-05:00
2020-08-27 00:52:11 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:11.004120-05:00
2020-08-27 00:52:12 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:12.002376-05:00
2020-08-27 00:52:13 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:13.004271-05:00
2020-08-27 00:52:14 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:14.002611-05:00
2020-08-27 00:52:15 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:15.003593-05:00
2020-08-27 00:52:16 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:16.003036-05:00
2020-08-27 00:52:17 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:17.003154-05:00
2020-08-27 00:52:18 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:18.002431-05:00
2020-08-27 00:52:19 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:19.004070-05:00
2020-08-27 00:52:20 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:20.004795-05:00
2020-08-27 00:52:21 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:21.003847-05:00
2020-08-27 00:52:22 ERROR (MainThread) [homeassistant.components.mylogger] The time is: 2020-08-26 19:52:22.002535-05:00

[balloob]

This looks good. It's wild that it can cost so much.

[bdraco]

I've been running it for a day now without any issues. My system is fast at getting time though so I'm not the best test here.

[balloob]

Let's get it running in dev/beta and see if we break something 👍