code: def test_nmf_explore_on_dummy_bert(self):
      lm = ecco.from_pretrained(
          "julien-c/bert-xsmall-dummy", activations=True, verbose=False
      )
      inputs = lm.to(
          lm.tokenizer(
              ["test", "hi"],
              padding=True,
              truncation=True,
              return_tensors="pt",
              max_length=512,
          )
      )
      output = lm(inputs)
      nmf = output.run_nmf()
      exp = nmf.explore(printJson=True)
  
      assert len(exp["tokens"]) == 3  # CLS UNK SEP
      # 1 redundant dimension,6 factors, 6 tokens (a batch of two examples, 3 tokens each)
      assert np.array(exp["factors"]).shape == (1, 6, 6)
  
imports: from ecco import output
  import pytest
  import torch
  import numpy
  from ecco.output import NMF
  import ecco
label_desc: Use image node_id 16 for calling the TestOutput obj's underlying member method code with example usage: obj.test_nmf_explore_on_dummy_bert() without return types