[Umbrella] Improve Test Code Coverage for Ignored Classes

[wuchong]

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Description

Our current test code coverage is below the desired threshold, leaving parts of the codebase untested and potentially prone to bugs or regressions. Increasing test coverage is critical to ensuring the reliability, maintainability, and long-term stability of our application.

We have temporarily ignored a lot of classes in the test-coverage: https://github.com/alibaba/fluss/blob/main/fluss-test-coverage/pom.xml#L247

We need to improve the code coverage by adding unit tests and integration tests around the classes, and remove them from the list.

Willingness to contribute

• I'm willing to submit a PR!

[wuchong]

The failed coverage for flink connector:

Warning:  Rule violated for class com.alibaba.fluss.flink.source.split.SnapshotSplit: lines covered ratio is 0.66, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.source.enumerator.initializer.NoStoppingOffsetsInitializer: lines covered ratio is 0.50, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.utils.CatalogExceptionUtils: lines covered ratio is 0.66, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.utils.DataLakeUtils: lines covered ratio is 0.45, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkHistogram.FlinkHistogramStatistics: lines covered ratio is 0.00, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkCounter: lines covered ratio is 0.00, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkMeter: lines covered ratio is 0.33, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkHistogram: lines covered ratio is 0.50, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.source.event.PartitionBucketsUnsubscribedEvent: lines covered ratio is 0.66, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.catalog.FlinkCatalog: lines covered ratio is 0.63, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.catalog.FlinkCatalogOptions: lines covered ratio is 0.66, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.source.reader.RecordAndPos: lines covered ratio is 0.47, but expected minimum is 0.70

https://github.com/alibaba/fluss/actions/runs/13965170459/job/39093809265

[gkatzioura]

I am putting a pr on this

[MehulBatra]

@gkatzioura Could you please Highlight which class you are targetting, I have already started working on com.alibaba.fluss.flink.catalog.FlinkCatalog & FlinkCatalogOptions
it would be great if we could create sub-issues and target one after the other, open for your thoughts!

[MehulBatra]

Link: #645 (comment)

[gkatzioura]

@MehulBatra
The metric ones

Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkHistogram.FlinkHistogramStatistics: lines covered ratio is 0.00, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkCounter: lines covered ratio is 0.00, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkMeter: lines covered ratio is 0.33, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.metrics.FlinkHistogram: lines covered ratio is 0.50, but expected minimum is 0.70
Warning:  Rule violated for class com.alibaba.fluss.flink.source.event.PartitionBucketsUnsubscribedEvent: lines covered ratio is 0.66, but expected minimum is 0.70

[MehulBatra]

Amazing, Please feel free to create a subissue for the same, and link them with this.
Thank you!