text: """
  The second test (b)in a series of tests to prove that this code works.
  
  Here are the tests:
  
  1. Gridded baselines, no thermal noise, no foregrounds
  2. Gridded baselines, thermal noise, no foregrounds
  2b. ** Gridded baselines, thermal noise, no foregrounds (numerically calculated noise).
  3. MWA baselines, thermal noise, no foregrounds
  4. Gridded baselines, thermal noise, point-source foregrounds
  5. MWA baselines, thermal noise, point-source foregrounds
  
  """
  from base_definitions import CustomCoreInstrument, CustomLikelihood, core_eor, run_mcmc, DEBUG
  from py21cmmc_fg.core import ForegroundsBase
  import numpy as np
  
  model_name = "InstrumentalGridTestNoiseNumerical"
  
  class NoFG(ForegroundsBase):
      def build_sky(self):
          return np.zeros((self.n_cells, self.n_cells, len(self.frequencies)))
  
  nofg = NoFG() #This is used *only* to trigger the numerical covariance. There should be a better way of doing this.
  
  
  core_instr = CustomCoreInstrument(
      antenna_posfile = 'grid_centres', # use a special grid of *baselines*.
      Tsys=240,
  )
  
  likelihood = CustomLikelihood(
      datafile=[f'data/{model_name}.npz'],
      noisefile=[f'data/{model_name}.noise.npz'],
  )
  
  if __name__ == "__main__":
      chain = run_mcmc(
          [core_eor, nofg, core_instr], likelihood,
          model_name=model_name,             # Filename of main chain output
      )
  
  