old_contents: import unittest
  
  from cupy import testing
  
  
  @testing.gpu
  class TestSolve(unittest.TestCase):
  
      _multiprocess_can_split_ = True
  
new_contents: import unittest
  
  import numpy
  
  import cupy
  from cupy import cuda
  from cupy import testing
  
  
  @unittest.skipUnless(
      cuda.cusolver_enabled, 'Only cusolver in CUDA 8.0 is supported')
  @testing.gpu
  class TestSolve(unittest.TestCase):
  
      _multiprocess_can_split_ = True
  
      @testing.for_float_dtypes(no_float16=True)
      def check_x(self, a_shape, b_shape, dtype):
          a_cpu = numpy.random.randint(0, 10, size=a_shape).astype(dtype)
          b_cpu = numpy.random.randint(0, 10, size=b_shape).astype(dtype)
          a_gpu = cupy.asarray(a_cpu)
          b_gpu = cupy.asarray(b_cpu)
          result_cpu = numpy.linalg.solve(a_cpu, b_cpu)
          result_gpu = cupy.linalg.solve(a_gpu, b_gpu)
          self.assertEqual(result_cpu.dtype, result_gpu.dtype)
          cupy.testing.assert_allclose(result_cpu, result_gpu, atol=1e-3)
  
      def check_shape(self, a_shape, b_shape):
          a = cupy.random.rand(*a_shape)
          b = cupy.random.rand(*b_shape)
          with self.assertRaises(numpy.linalg.LinAlgError):
              cupy.linalg.solve(a, b)
  
      def test_solve(self):
          self.check_x((4, 4), (4,))
          self.check_x((5, 5), (5, 2))
  
      def test_invalid_shape(self):
          self.check_shape((2, 3), (4,))
          self.check_shape((3, 3), (2,))
          self.check_shape((3, 3, 4), (3,))
  
subject: Add tests