Testing: Dynamic enablement/disablement of backends

[kurtmcmillan]

Motivation

Tests sometimes want to test a specific backend. Before this change backends were enabled by default and disabled using environment variables. Once the environment variables were parsed and the backends instantiated there was no way to modify which backends were enabled.

With this change all backends are always instantiated. Each backend checks its enablement when scoring and performing IO. Functions have been added to allow tests to dynamically change the enablement of each backend.

AIHIPFILE-157

[Copilot]

Pull request overview

This PR enables tests to dynamically enable/disable AMD backends at runtime by always instantiating all backends and making backend selection/IO consult Context<Configuration> at call time, rather than relying on one-time environment-variable parsing during initialization.

Changes:

• Refactors AMD Configuration to support runtime override of fastpath/fallback enablement and makes env/proc-address checks lazy.
• Updates backend instantiation/selection: always create Fastpath/Fallback; each backend now checks enablement in score()/io() and can throw BackendDisabled.
• Updates AMD unit/system tests and mocks to use the new configuration override approach; adjusts test CMake sources accordingly.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
test/system/amd/io.cpp	Switches system IO tests from env-var toggles to runtime Configuration enablement.
test/amd_detail/stats.cpp	Adds MConfiguration to control statsLevel() in StatsServer lifetime test.
test/amd_detail/mconfiguration.h	Introduces a Configuration mock with ContextOverride<Configuration>.
test/amd_detail/hipfile-api.cpp	Adds coverage for hipFileIo when backend io() throws BackendDisabled.
test/amd_detail/fastpath.cpp	Updates fastpath tests to expect config-gated scoring/IO via MConfiguration.
test/amd_detail/fallback.cpp	Updates fallback tests to expect config-gated scoring/IO via MConfiguration.
test/amd_detail/configuration.cpp	Reworks configuration tests around lazy env/proc checks + runtime overrides.
test/CMakeLists.txt	Moves system IO test source to AMD-only path.
src/amd_detail/static.h	Adds STATIC macro to disable function-local static caching under tests.
src/amd_detail/state.cpp	Always instantiates both backends rather than conditionally constructing them.
src/amd_detail/hip.cpp	Uses STATIC for cached proc-address function pointers.
src/amd_detail/configuration.h	Refactors configuration interface into overridable methods + override state.
src/amd_detail/configuration.cpp	Implements lazy env/proc checks and runtime override storage.
src/amd_detail/backend/fastpath.cpp	Gates scoring/IO on Configuration::fastpath(); throws BackendDisabled when disabled.
src/amd_detail/backend/fallback.cpp	Gates scoring/IO on Configuration::fallback(); throws BackendDisabled when disabled.
src/amd_detail/backend.h	Adds BackendDisabled exception type.

Comments suppressed due to low confidence (1)

test/system/amd/io.cpp:90

• HipFileIo::SetUp() mutates the global Context<Configuration> enablement but TearDown() never restores it. Because system tests run in a single process, this can leak backend enablement state into later test cases and create order-dependent failures. Consider saving the previous fastpath()/fallback() values at the start of SetUp() and restoring them in TearDown() (or explicitly re-enabling both backends after each test).

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[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

test/system/amd/io.cpp:70

• SetUp() mutates the global Context<Configuration> enablement (disables both backends, then enables one) but TearDown() doesn’t restore the previous configuration. Because system tests run in a single process, this can make later tests order-dependent (e.g., leaving fastpath disabled after the final parameterized case). Consider saving the prior fastpath/fallback values at the start of SetUp() and restoring them in TearDown() (or otherwise resetting to a known default) to avoid cross-test contamination.

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