[AutoTuner] Add unit tests for parse_flow_variables() and parse_tunable_variables()

[harsh-kumar-patwa]

Summary

parse_flow_variables() and parse_tunable_variables() in tools/AutoTuner/src/autotuner/utils.py have explicit TODO: Tests. comments but currently lack any unit test coverage.

These are core parsing functions in the AutoTuner pipeline:

• parse_flow_variables() — Invokes make vars, then extracts environment variable names from env() patterns across Tcl scripts and vars.tcl. Used to determine the set of valid flow variables.
• parse_tunable_variables() — Reads variables.yaml and returns the set of variables marked with tunable: 1. Used to validate which variables the AutoTuner is allowed to tune.

Proposed Test Coverage

parse_tunable_variables() (7 tests)

• Returns a non-empty set
• Known tunable variables (e.g., CORE_UTILIZATION, CORE_AREA) are present
• Non-tunable variables (e.g., EQUIVALENCE_CHECK, DETAILED_METRICS) are excluded
• Correctly filters on tunable: 1 flag (with mock YAML)
• Handles empty YAML and YAML with no tunable variables

parse_flow_variables() (6 tests)

• Exits on Makefile failure (non-zero return code)
• Exits when vars.tcl is not generated
• Passes correct platform argument to make
• Extracts env() patterns from Tcl files
• Uppercases all variable names
• Deduplicates variables (returns a set)

[harsh-kumar-patwa]

I'd like to work on this. Will raise a PR soon.