Remove accidental dependency of 'swh-identify' on swh-core

Was added in be8f1a55

swh/model/cli.py

@@ -11,7 +11,12 @@ from typing import Dict, List, Optional
 # control
 import click
 
-from swh.core.cli import swh as swh_cli_group
+try:
+    from swh.core.cli import swh as swh_cli_group
+except ImportError:
+    # stub so that swh-identify can be used when swh-core isn't installed
+    swh_cli_group = click  # type: ignore
+
 from swh.model.identifiers import CoreSWHID, ObjectType
 
 CONTEXT_SETTINGS = dict(help_option_names=["-h", "--help"])

tox.ini

 [tox]
-envlist=black,flake8,mypy,py3
+envlist=black,flake8,mypy,py3,identify
 
 [testenv]
 extras =
@@ -12,6 +12,15 @@ commands =
          {envsitepackagesdir}/swh/model \
            --cov-branch {posargs}
 
+[testenv:identify]
+# no 'extras = testing', as it would install swh-core;
+# and this test is designed to check 'swh-identify' does not depend on swh-core.
+extras =
+deps =
+  -r requirements-test.txt
+commands =
+  pytest {envsitepackagesdir}/swh/model/tests/test_cli.py
+
 [testenv:black]
 skip_install = true
 deps =