[CI] Enable multi-GPU pytest workflow

.github/workflows/test-fabric-multi-gpu.yaml

@@ -14,19 +14,12 @@
 
 name: FabricFrameView Multi-GPU Tests
 
-# DISABLED: No self-hosted runner with the 'multi-gpu' label is currently
-# registered.  All runs queue indefinitely.  Re-enable once infra provisions
-# a multi-GPU runner (see also .github/workflows/test-multi-gpu.yaml which
-# has the same issue).
-#
-# on:
-#   pull_request:
-#     paths:
-#       - "source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py"
-#       - "source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py"
-#       - ".github/workflows/test-fabric-multi-gpu.yaml"
-#   workflow_dispatch:
 on:
+  pull_request:
+    paths:
+      - "source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py"
+      - "source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py"
+      - ".github/workflows/test-fabric-multi-gpu.yaml"
   workflow_dispatch:
 
 concurrency:
@@ -37,13 +30,43 @@ jobs:
   test-fabric-multi-gpu:
     name: FabricFrameView multi-GPU unit tests
     runs-on: [self-hosted, linux, x64, gpu, multi-gpu]
-    timeout-minutes: 30
+    timeout-minutes: 60
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install cmake via pip (avoid sudo apt path)
+        # install.py skips its sudo apt-get block when ``cmake`` is already on
+        # PATH (source/isaaclab/isaaclab/cli/commands/install.py:35).  The
+        # pip wheel provides a cmake shim under the setup-python venv's bin/,
+        # which is on PATH, so installing it here bypasses the apt branch.
+        run: pip install cmake
+
       - name: Install Isaac Lab
-        run: ./isaaclab.sh --install
+        # ``--install none`` = core submodules only (no mimic, no teleop, no
+        # auto-extra features).  The FabricFrameView cuda:1 tests only need
+        # isaaclab core + isaaclab_physx + Isaac Sim.  Avoids building
+        # robomimic's egl_probe wheel, which requires libEGL/X11 headers
+        # that the multi-GPU runner image lacks.
+        run: ./isaaclab.sh --install none
+
+      - name: Install Isaac Sim
+        # Isaac Sim is an optional extra in source/isaaclab/setup.py and is
+        # not pulled by ``--install none``.  Without it, AppLauncher's
+        # ``import isaacsim`` is silently caught by
+        # ``contextlib.suppress(ModuleNotFoundError)``, ``EXP_PATH`` stays
+        # unset, and test collection crashes with ``KeyError: 'EXP_PATH'``.
+        #
+        # Pinned to 6.0.0.0 because that is the only release line with a
+        # Python 3.12 wheel.  The 5.x line on PyPI requires Python 3.11
+        # (and source/isaaclab/setup.py's ``isaacsim==5.1.0`` pin is stale
+        # relative to the 3.12 baseline declared in pyproject.toml).
+        run: pip install 'isaacsim[all,extscache]==6.0.0.0'
 
       - name: Verify multi-GPU availability
         # Fail loud if the runner regressed to a single GPU.  Without this, the
@@ -64,6 +87,13 @@ jobs:
       - name: Run FabricFrameView multi-GPU unit tests
         env:
           ISAACLAB_TEST_MULTI_GPU: "1"
+          # Bypass Kit's interactive EULA prompt on first launch.  Without
+          # these, isaacsim.bootstrap_kernel reads stdin during test
+          # collection and pytest aborts with
+          # ``pytest: reading from stdin while output is captured``.
+          OMNI_KIT_ACCEPT_EULA: "yes"
+          ACCEPT_EULA: "Y"
+          ISAAC_SIM_HEADLESS: "1"
         run: |
           ./isaaclab.sh -p -m pytest \
             source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py -v