feat: add channel_labels

[abawchen]

Add channel_labels and pass unittest.

[abawchen]

@castillohair @JS3xton : Please help review this one, thanks.

[JS3xton]

Thanks for the contribution. I found some small things, but otherwise looks good to me.

1. The channel_labels method should be described in the FCSData docstring.
2. It would be nice to explicitly unit test channel_labels like other similar methods (e.g. the TestFCSAttributesDetectorVoltage class in /test/test_io.py).

[JS3xton]

3. Add channel_labels method to TestFCSDataPickle in /test/test_io.py.

[abawchen]

@JS3xton : Thanks for feedback, I will update accordingly.

[abawchen]

@JS3xton : I have a quick question, because all of the current testing fcs files don't have label value, i.e. they don't have $PnS key, and will return [None, None, ..., None] of all channels -- should I modify the current testing fcs file or create another one?

[JS3xton]

@JS3xton : I have a quick question, because all of the current testing fcs files don't have label value, i.e. they don't have $PnS key, and will return [None, None, ..., None] of all channels -- should I modify the current testing fcs file or create another one?

@abawchen Hmm, good point. I wouldn't modify the existing files. If you have a new file you can contribute, that seems fine to me. Otherwise, you might be able to find one in this repository: https://flowrepository.org/id/FR-FCM-ZZZ4.

[castillohair]

@JS3xton , I added the description of channel_labels into the FCSData docstring. I also added it to the TestFCSDataPickle test.

@abawchen I think we would still prefer if you could incorporate an FCS file that actually contains $PnS keys and make unit tests for it. Code looks good, but we still have no "experimental" evidence that it does what it's supposed to do.

[abawchen]

@JS3xton @castillohair :
Hi, thanks your feedback, although it's been a while 😅
I have added Data005.fcs and add corresponding test case as you suggested, please help check it.

btw, I have rebase the updated develop branch.

[castillohair]

The last element of this list should be 'Time (204.80 sec.)'. This is what you have later in the test_attribute() function.

[castillohair]

In my opinion, the proposed unit tests validate that the feature works as expected. I have one observation in the test class docstring though. @JS3xton see what you think.

[JS3xton]

Looks good to me.

(The new data file is kinda large, though... ~16MB)

[castillohair]

@abawchen thanks for the contribution! We will release it with the new FlowCal version soon.