Let tests replace the IBV wrapper instead of editing it

[derobins]

Tests used to fake libibverbs by writing into the library's own wrapper through funcsForTest() and setting its public is_initialized field, then copying the saved table back. Entries a test didn't fake still called the real libibverbs, with fake pointers.

IBVWrapper now has a second constructor that takes an IbvFuncs table and loads nothing, and setIbvForTest() installs a wrapper for ibv() to return, like setStateForTest(). ibv() checks the override before creating the library's own wrapper, so tests that install fakes never load libibverbs. is_initialized is private, with a read-only is_initialized(), and funcsForTest() is removed.

• Add hipObjTest::ScopedFakeIbv (test/unit/fake-ibv.h), which installs a wrapper built from fakes for its lifetime and restores the previous one. replace() switches fakes mid-test.
• The fixtures build their fakes from an empty table, so a verb a test doesn't fake is a null call rather than a call into libibverbs. The IbvFakeInstall and FakeDestroyVerbs classes become functions that return the fakes.
• Add test-ibv-lazy-load, which checks in a program of its own that libibverbs isn't loaded until the first ibv() call.
• Add a test that HIPOBJ_DMABUF set after the program starts is honored by a wrapper created afterward.
• test-seams checks that setIbvForTest() redirects ibv().

[Copilot]

🟢 Approval recommended

The test seam and fixture migrations preserve resource lifetimes while preventing unintended calls into libibverbs.

0 open findings

What changed in this PR

Refactors libibverbs test seams so tests install isolated fake wrappers without loading or modifying the production wrapper.

Changes:

• Adds ScopedFakeIbv and wrapper override support.
• Migrates fixtures to explicit fake function tables.
• Adds lazy-loading and runtime environment-setting tests.

File	Description
src/​common/​ibv-wrapper.h	Adds fake-table construction and override APIs.
src/​common/​ibv-wrapper.cpp	Implements wrapper overrides and initialization encapsulation.
src/​hipobj.cpp	Uses the read-only initialization accessor.
test/​integration/​rdma-test-server/​rdma_server.cpp	Updates initialization checking.
test/​unit/​CMakeLists.txt	Registers the lazy-loading test.
test/​unit/​fake-ibv.h	Adds scoped fake-wrapper management.
test/​unit/​fake-device.h	Stores the scoped fake wrapper.
test/​unit/​fake-device.cpp	Installs isolated fake verbs.
test/​unit/​test-api-exceptions.cpp	Replaces fake verbs safely during tests.
test/​unit/​test-buffer-registration.cpp	Migrates registration tests to the new seam.
test/​unit/​test-ibv-dmabuf.cpp	Tests replacement wrappers and environment rereading.
test/​unit/​test-ibv-lazy-load.cpp	Verifies first-use libibverbs loading.
test/​unit/​test-seams.cpp	Tests redirection through the IBV seam.
test/​unit/​test-thread-safety.cpp	Migrates thread-safety fixtures to isolated fakes.
test/​unit/​test-v2-conflict.cpp	Uses replaceable fake verb tables.
test/​unit/​test-v2-connref.cpp	Migrates fault tests to scoped fakes.
test/​unit/​test-v2-random.cpp	Installs fake PSN-related verbs.
test/​unit/​test-v2-registry.cpp	Migrates registry fixtures to scoped fakes.
test/​unit/​test-v2-server.cpp	Installs scoped no-op destruction verbs.

🧠 Review effort: Balanced

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