add unit test for is_a_yaml_with_class

import os

import tempfile

from galaxy.tool_util.loader_directory import is_a_yaml_with_class

def test_is_a_yaml_with_class():

    with tempfile.NamedTemporaryFile("w", suffix=".yaml", delete=False) as tf:

        fname = tf.name

        tf.write("""class: GalaxyWorkflow

name: "Test Workflow"

inputs:

  - id: input1

outputs:

  - id: wf_output_1

    outputSource: first_cat/out_file1

steps:

  - tool_id: cat

    label: first_cat

    in:

      input1: input1""")

    assert is_a_yaml_with_class(fname, ["GalaxyWorkflow"])

    os.unlink(fname)

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