Benthos tests don't recognise template components

Given this foo.tmpl.yaml:

name: foobar
type: processor
fields:
  - name: foo
    type: string

mapping: |
  #!blobl
  root.mapping = "root.foo = \"" + this.foo + "\""

And foo.yaml:

input:
  generate:
    count: 1
    mapping: root = ""

pipeline:
    processors:
      - foobar:
          foo: bar

output:
  stdout: {}

tests:
  - name: example test
    target_processors: '/pipeline/processors'
    environment: {}
    input_batch:
      - content: ""
    output_batches:
      -
        - json_equals: '{ "foo": "bar" }'

This command:

$ benthos test -t foo.tmpl.yaml foo.yaml

Fails with:

Failed to execute test target 'foo.yaml': test case 0 failed: failed to initialise processors '/pipeline/processors': failed to initialise processor index '0': processor type of 'foobar' was not recognised

Run benthos test -t foo.tmpl.yaml foo.yaml with the two issue examples and confirm the unrecognised foobar processor error. Trace how the benthos test command loads template components before initialising /pipeline/processors; done means the test recognises foobar and produces the expected { "foo": "bar" } output.