class_docstr: Test that an artifact defined in the first step
  is available in all steps downstream.
class_docstr_tok: ["Test","that","an","artifact","defined","in","the","first","step","is","available","in","all","steps","downstream","."]
code: def step_all(self):
      pass
  
imports: from metaflow_test import MetaflowTest, ExpectationFailed, steps
label_desc: Use image node_id 3 for calling the BasicArtifactTest obj's underlying member method code with example usage: obj.step_all() without return types