crates:
- name: A
  deps:
  - B
- name: B
  deps:
  - C
- name: C
  deps:
  - D
- name: D
cases:
- cmd: trace A B
  stdout: |
    A -> B
- cmd: trace A C
  stdout: |
    A -> B -> C
- cmd: trace B D
  stdout: |
    B -> C -> D
- cmd: trace A D
  stdout: |
    A -> B -> C -> D