test(rccl): add host microtests for src/bootstrap.cc

projects/rccl/test/host/CMakeLists.txt

@@ -257,6 +257,19 @@ function(rccl_define_micro_source_lists)
     ../common/ProcessIsolatedTestRunner.cpp
     PARENT_SCOPE)
 
+  # rccl-UnitTestsMicroBootstrap -- src/bootstrap.cc. Own binary: bootstrap_micro_fakes.cc replaces misc/socket.cc
+  # wholesale, and other binaries link bootstrap_stubs.cc for this unit's symbols.
+  set(TEST_MICRO_BOOTSTRAP_SOURCE_FILES
+    bootstrap-test.cc
+    fakes/bootstrap_micro_fakes.cc
+    fakes/env_fakes.cc
+    fakes/hip_fakes.cc
+    fakes/nccl_fakes.cc
+    fakes/os_fakes.cc
+    ${RCCL_HOST_HIPIFY_DIR}/src/misc/utils.cc
+    ../common/main_altrsmi.cpp
+    PARENT_SCOPE)
+
   # rccl-UnitTestsMicroWarpSpeed -- scheduler UUTs under ENABLE_WARP_SPEED.
   set(TEST_MICRO_SCHEDULER_SOURCE_FILES
     scheduler-test.cc
@@ -1337,6 +1350,16 @@ endif()
 # all targets -- no need to repeat it per binary.
 rccl_mark_oracle_tus_generated(${RCCL_HOST_HIPIFY_DIR} argcheck archinfo utils kernel_config)
 
+# ---------------------------------------------------------------------------
+# rccl-UnitTestsMicroBootstrap
+# ---------------------------------------------------------------------------
+rccl_add_micro_binary(rccl-UnitTestsMicroBootstrap
+  SOURCES ${TEST_MICRO_BOOTSTRAP_SOURCE_FILES}
+  EXTRA_DEFS
+    ${_MICRO_MODE_DEFS}
+    BOOTSTRAP_CC_PATH="${RCCL_HOST_HIPIFY_DIR}/src/bootstrap.cc"
+  CATEGORIES_YAML "${CMAKE_CURRENT_SOURCE_DIR}/../test_categories_micro_bootstrap.yaml")
+
 # ---------------------------------------------------------------------------
 # rccl-UnitTestsMicro
 # ---------------------------------------------------------------------------

projects/rccl/test/host/MICROTEST_README.md

@@ -227,6 +227,11 @@ export colliding non-`static` symbols; otherwise a unit needs its own binary:
     tables, prime strides, Walecki, Walecki+greedy) and the load-balanced cut
     selection in `findRingCutIndices`. `greedyRingGen`'s out-of-memory arm is
     driven through the heap half of `fakes/libc_seam.h`.
+- **`rccl-UnitTestsMicroBootstrap`**: `bootstrap.cc` (via `BOOTSTRAP_CC_PATH`, from
+  `bootstrap-test.cc`); suites `Bootstrap*Microtest.*`. Ranks run as threads over the
+  in-memory socket layer and net plugin in `fakes/bootstrap_micro_fakes.cc`. Its own binary
+  because those seams replace `misc/socket.cc` wholesale, and other binaries link
+  `bootstrap_stubs.cc` for this unit's symbols. See `test_categories_micro_bootstrap.yaml`.
 - **`rccl-UnitTestsMicroEnqueue`** — `enqueue.cc` (via `ENQUEUE_CC_PATH`); suite
   `EnqueueMicrotest.*`. All tests live in `enqueue-test.cc`, grouped by unit under
   test; several fixtures are reused by later groups, so the order within the file
@@ -610,6 +615,7 @@ symbol.
 | `src/algorithms/dda/*.cc` (targets that do not compile the real file) | `fakes/dda_fakes.cc` |
 | `src/allocator.cc` | `fakes/allocator_fakes.cc` |
 | `src/bootstrap.cc` | `fakes/bootstrap_stubs.cc` |
+| externals `src/bootstrap.cc` reaches (`rccl-UnitTestsMicroBootstrap`, which compiles it) | `fakes/bootstrap_micro_fakes.cc` |
 | `src/ce_coll.cc` (targets that do not compile the real file) | `fakes/ce_fakes.cc` |
 | `src/collectives.cc` | `fakes/collectives_fakes.cc` |
 | `src/dev_runtime.cc` (targets that do not compile the real file) | `fakes/dev_runtime_fakes.cc` |
@@ -1034,6 +1040,7 @@ cd projects/rccl/test/host
 cmake -B build -DCMAKE_BUILD_TYPE=Release \
       -DRCCL_BUILD_DIR=/path/to/projects/rccl/build/release
 cmake --build build -j"$(nproc)"
+./build/rccl-UnitTestsMicroBootstrap          # src/bootstrap.cc tests
 ./build/rccl-UnitTestsMicro          # p2p tests, ldd shows no HIP/ROCm/HSA/RCCL
 ./build/rccl-UnitTestsMicroCollectives        # src/collectives.cc tests
 ./build/rccl-UnitTestsMicroOnerank            # src/device/onerank.cu tests