Brittle tests against response contents

[shonfeder]

In the opam-repo-ci, the curly tests are failing on an update to cohttp in a way that I think indicates brittleness of the tests rather than a breaking API problem. E.g.,

# ┌──────────────────────────────────────────────────────────────────────────────┐
# │ [FAIL]        curly          1   read_header.                                │
# └──────────────────────────────────────────────────────────────────────────────┘
# ASSERT read_header
# FAIL read_header
# 
#    Expected: `Ok {code=200; headers=connection: keep-alive
# 
# content-length: 12
# ; body="header value"}'
#    Received: `Ok {code=200; headers=content-length: 12
# ; body="header value"}'

I expect that either the tests should be updated, or written so that they only check that the minimal required headers are present, rather than be coded against the exact content and order.