[Misc] added unit tests for apa autoscaling

[harryge00]

Pull Request Description

Added unit tests for APA autoscaling

Related Issues

Tests:

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[gemini-code-assist]

Summary of Changes

Hello @harryge00, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the test coverage for the ApaScalingAlgorithm by introducing a new set of unit tests for its ComputeTargetReplicas function. These tests are crucial for validating the correctness and robustness of the autoscaling logic, ensuring that the algorithm accurately calculates target replica counts based on current usage, target values, fluctuation tolerances, and scaling rate limits. This enhancement improves the reliability and maintainability of the autoscaler component.

Highlights

• New Unit Test File: Added a new unit test file, apa_test.go, specifically for the ApaScalingAlgorithm.
• Comprehensive Test Cases: Introduced a suite of test cases for the ComputeTargetReplicas function, covering various scenarios including no scaling within tolerance, scaling up/down beyond tolerance thresholds, and scaling limited by maximum rates.
• Algorithm Validation: Verified the ApaScalingAlgorithm's behavior under different load conditions and configuration parameters, ensuring accurate replica computation.

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[gemini-code-assist]

Code Review

This pull request adds a good set of unit tests for the APA scaling algorithm. The tests cover various scenarios including scaling up, scaling down, and respecting tolerances and rate limits. My review focuses on enhancing the test suite by adding coverage for critical edge cases in the scale-down logic that could lead to bugs. I've identified issues with how MaxScaleDownRate is handled when it's zero or less than one, and I'm suggesting new test cases to expose and help fix these vulnerabilities.