Add job to run NVTabular unit tests on GPU

Author: oliverholworthy

.github/workflows/merlin.yml

@@ -32,4 +32,11 @@ jobs:
     name: "NVTabular (CPU)"
     uses: ./.github/workflows/tox.yml
     with:
-      env: test-nvtabular-cpu
+      env: test-nvtabular
+
+  nvtabular-gpu:
+    runs-on: 1GPU
+    name: "NVTabular (GPU)"
+    uses: ./.github/workflows/tox.yml
+    with:
+      env: test-nvtabular

tox.ini

@@ -52,7 +52,12 @@ commands =
     python -m pytest --cov-report term --cov merlin -rxs tests/unit
 
 
-[testenv:test-nvtabular-cpu]
+[testenv:test-nvtabular]
+setenv =
+    TF_GPU_ALLOCATOR=cuda_malloc_async
+passenv =
+    OPAL_PREFIX
+    CUDA_VISIBLE_DEVICES
 passenv=GIT_COMMIT
 sitepackages=true
 allowlist_externals = git