class_docstr: we test data loading, model instantiation, forecasting consistency, in particular
  (1) load a testing data
  (2) transform data
  (3) instantiate the model and train
  (4) forecast, and the forecasting result agrees with the reference
code: def __init__(self, *args, **kwargs):
      super().__init__(*args, **kwargs)
  
      self.max_forecast_steps = 10
      self.i = 0
  
      dataset = "seattle_trail"
      d, md = SeattleTrail(
          rootdir=join(rootdir, "data", "multivariate", dataset)
      )[0]
      t = int(d[md["trainval"]].index[-1].to_pydatetime().timestamp())
      data = TimeSeries.from_pd(d)
      cleanup_transform = TransformSequence(
          [
              TemporalResample(missing_value_policy="FFill"),
              LowerUpperClip(upper=300),
          ]
      )
      cleanup_transform.train(data)
      data = cleanup_transform(data)
  
      train_data, test_data = data.bisect(t)
  
      minmax_transform = MinMaxNormalize()
      minmax_transform.train(train_data)
      self.train_data_norm = minmax_transform(train_data)
      self.test_data_norm = minmax_transform(test_data)
  
      self.model = DefaultForecaster(
          DefaultForecasterConfig(target_seq_index=self.i)
      )
  
imports: import logging
  from os.path import abspath, dirname, join
  import sys
  import unittest
  import pandas
  from merlion.evaluate.forecast import ForecastMetric
  from merlion.models.defaults import DefaultForecaster, DefaultForecasterConfig
  from merlion.models.utils.rolling_window_dataset import RollingWindowDataset
  from merlion.transform.bound import LowerUpperClip
  from merlion.transform.normalize import MinMaxNormalize
  from merlion.transform.resample import TemporalResample
  from merlion.transform.sequence import TransformSequence
  from merlion.utils.time_series import TimeSeries, to_pd_datetime
  from ts_datasets.forecast import SeattleTrail
label_desc: Use image node_id 1 to create a new TestMultivariate object from inherited base classes: unittest with example: obj = TestMultivariate()