tweak ci for unit tests

.circleci/config.yml

@@ -91,7 +91,7 @@ commands:
 jobs:
   unit_test:
     macos:
-      xcode: "15.4.0"
+      xcode: "16.0.0"
     resource_class: macos.m1.medium.gen1
     steps:
       - checkout
@@ -113,7 +113,7 @@ jobs:
             source env/bin/activate
             # set TEMPERATURE to 0 for deterministic sampling
             echo "Running inference engine tests..."
-            METAL_XCODE=1 TEMPERATURE=0 python3 -m exo.inference.test_inference_engine
+            LOW_MEMORY=1 DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 METAL_XCODE=1 TEMPERATURE=0 python3 -m exo.inference.test_inference_engine
             echo "Running tokenizer tests..."
             python3 ./test/test_tokenizers.py