class_docstr: Test the BackendValidator class.
class_docstr_tok: ["Test","the","BackendValidator","class","."]
code: def setup_method(self):
      # mock missing dependency error for non existent module
      ERROR_TYPES["backend_B"] = "optional-deps"
      ERROR_TYPES["backend_E"] = "backend_E"
      ERROR_TYPES["backend_D"] = "backend_D"
      HAS_BACKEND["backend_A"] = True
      HAS_BACKEND["backend_B"] = False
      HAS_BACKEND["backend_C"] = True
      HAS_BACKEND["backend_D"] = False
      HAS_BACKEND["backend_E"] = False
  
imports: import pytest
  from alibi_detect.utils.missing_optional_dependency import ERROR_TYPES
  from alibi_detect.utils.frameworks import BackendValidator, HAS_BACKEND
label_desc: Use image node_id 1 for calling the TestBackendValidator obj's underlying member method code with example usage: obj.setup_method() without return types