polish unitest test with titans (#1152)

tests/test_data_pipeline_tensor_parallel/test_cifar_with_data_pipeline_tensor.py

@@ -16,12 +16,10 @@ from colossalai.core import global_context as gpc
 from colossalai.logging import get_dist_logger
 from colossalai.nn import CrossEntropyLoss
 from colossalai.nn.lr_scheduler import CosineAnnealingWarmupLR
-from colossalai.utils import is_using_pp, get_dataloader
+from colossalai.utils import get_dataloader
 from colossalai.pipeline.pipelinable import PipelinableContext
-from tqdm import tqdm
 from torchvision.datasets import CIFAR10
 from torchvision import transforms
-from titans.model.vit import vit_tiny_patch4_32
 
 BATCH_SIZE = 4
 NUM_EPOCHS = 60
@@ -41,6 +39,12 @@ def run_trainer(rank, world_size, port):
     logger = get_dist_logger()
 
     pipelinable = PipelinableContext()
+    try:
+        from titans.model.vit import vit_tiny_patch4_32
+    except ImportError:
+        logger.warning('skip the test_cifar_with_data_pipeline_tensor test because titan is not installed')
+        logger.warning('please install titan from https://github.com/hpcaitech/Titans')
+        return
     with pipelinable:
         model = vit_tiny_patch4_32()
     pipelinable.to_layer_list()