old_contents: import astropy.units as u
  import numpy as np
  
  import plasmapy.classes
  
  
  class TestPlasma(object):
      def test_patters(self):
          # Input data whose specific subclass cannot be known
          generic = plasmapy.classes.Plasma(blablobleh='spam')
          assert isinstance(generic, plasmapy.classes.GenericPlasma)
  
      def test_Plasma3D(self):
          # Input data for Plasma3D
          three_dimensional = plasmapy.classes.Plasma(domain_x=np.linspace(0, 1, 3) * u.m,
                                                      domain_y=np.linspace(0, 1, 3) * u.m,
                                                      domain_z=np.linspace(0, 1, 3) * u.m)
          assert isinstance(three_dimensional, plasmapy.classes.sources.Plasma3D)
          assert isinstance(three_dimensional, plasmapy.classes.BasePlasma)
  
      def test_PlasmaBlob(self):
          # Input data for PlasmaBlob
          T_e = 25 * 15e3 * u.K
          n_e = 1e26 * u.cm ** -3
          Z = 2.0
          particle = 'p'
          blob = plasmapy.classes.Plasma(T_e=T_e,
                                         n_e=n_e,
                                         Z=Z,
                                         particle=particle)
          assert isinstance(blob, plasmapy.classes.sources.PlasmaBlob)
          assert isinstance(blob, plasmapy.classes.BasePlasma)
  
new_contents: import astropy.units as u
  import numpy as np
  
  import plasmapy.classes
  
  
  class TestPlasma(object):
      def test_patters(self):
          # Input data whose specific subclass cannot be known
          generic = plasmapy.classes.Plasma(blablobleh='spam')
          assert isinstance(generic, plasmapy.classes.GenericPlasma)
  
      def test_Plasma3D(self):
          # Input data for Plasma3D
          three_dimensional = plasmapy.classes.Plasma(domain_x=np.linspace(0, 1, 3) * u.m,
                                                      domain_y=np.linspace(0, 1, 3) * u.m,
                                                      domain_z=np.linspace(0, 1, 3) * u.m)
          assert isinstance(three_dimensional, plasmapy.classes.sources.Plasma3D)
          assert isinstance(three_dimensional, plasmapy.classes.BasePlasma)
  
      def test_PlasmaBlob(self):
          # Input data for PlasmaBlob
          T_e = 25 * 15e3 * u.K
          n_e = 1e26 * u.cm ** -3
          Z = 2.0
          particle = 'p'
          blob = plasmapy.classes.Plasma(T_e=T_e,
                                         n_e=n_e,
                                         Z=Z,
                                         particle=particle)
          assert isinstance(blob, plasmapy.classes.sources.PlasmaBlob)
          assert isinstance(blob, plasmapy.classes.BasePlasma)
  
      def test_HDF5Reader(self):
          h5 = plasmapy.classes.Plasma(hdf5='virtual_hdf5.h5')
          assert isinstance(h5, plasmapy.classes.sources.HDF5Reader)
          assert isinstance(h5, plasmapy.classes.BasePlasma)
  
subject: Add test for Plasma HDF5Reader subclass