code: def test_matmul(*, x, y, test_flags, backend_fw, fn_name, on_device):
      input_dtype1, x_1, transpose_a, adjoint_a = x
      input_dtype2, y_1, transpose_b, adjoint_b = y
      helpers.test_function(
          input_dtypes=input_dtype1 + input_dtype2,
          test_flags=test_flags,
          backend_to_test=backend_fw,
          fn_name=fn_name,
          on_device=on_device,
          rtol_=1e-1,
          atol_=1e-1,
          x1=x_1,
          x2=y_1,
          transpose_a=transpose_a,
          transpose_b=transpose_b,
          adjoint_a=adjoint_a,
          adjoint_b=adjoint_b,
      )
  
imports: import sys
  import numpy
  from hypothesis import assume, strategies
  import ivy_tests.test_ivy.helpers
  from ivy_tests.test_ivy.helpers import handle_test, BackendHandler
  from ivy_tests.test_ivy.helpers.hypothesis_helpers.general_helpers import matrix_is_stable
label_desc: Use image node_id 19 for calling a global function with example usage: test_matmul() without return types