diff --git a/conftest.py b/conftest.py
--- a/conftest.py
+++ b/conftest.py
@@ -1,6 +1,20 @@
+import pytest
 from hypothesis import settings
 
+from swh.core.cli import swh as _swhmain
+
 # define tests profile. Full documentation is at:
 # https://hypothesis.readthedocs.io/en/latest/settings.html#settings-profiles
 settings.register_profile("fast", max_examples=5, deadline=5000)
 settings.register_profile("slow", max_examples=20, deadline=5000)
+
+
+@pytest.fixture
+def swhmain():
+    """Yield an instance of the main `swh` click command that cleans the added
+    subcommands up on teardown."""
+    commands = _swhmain.commands.copy()
+    aliases = _swhmain.aliases.copy()
+    yield _swhmain
+    _swhmain.commands = commands
+    _swhmain.aliases = aliases
diff --git a/swh/core/db/tests/test_cli.py b/swh/core/db/tests/test_cli.py
--- a/swh/core/db/tests/test_cli.py
+++ b/swh/core/db/tests/test_cli.py
@@ -2,7 +2,6 @@
 
 from click.testing import CliRunner
 
-from swh.core.cli import swh as swhmain
 from swh.core.cli.db import db as swhdb
 
 
@@ -28,7 +27,7 @@
 '''
 
 
-def test_swh_help():
+def test_swh_help(swhmain):
     swhmain.add_command(swhdb)
     runner = CliRunner()
     result = runner.invoke(swhmain, ['-h'])
@@ -49,7 +48,7 @@
 '''
 
 
-def test_swh_db_help():
+def test_swh_db_help(swhmain):
     swhmain.add_command(swhdb)
     runner = CliRunner()
     result = runner.invoke(swhmain, ['db', '-h'])
diff --git a/swh/core/tests/test_cli.py b/swh/core/tests/test_cli.py
--- a/swh/core/tests/test_cli.py
+++ b/swh/core/tests/test_cli.py
@@ -7,8 +7,6 @@
 from click.testing import CliRunner
 import pytest
 
-from swh.core.cli import swh as swhmain
-
 
 help_msg = '''Usage: swh [OPTIONS] COMMAND [ARGS]...
 
@@ -29,7 +27,7 @@
 '''
 
 
-def test_swh_help():
+def test_swh_help(swhmain):
     runner = CliRunner()
     result = runner.invoke(swhmain, ['-h'])
     assert result.exit_code == 0
@@ -40,7 +38,7 @@
     assert result.output.startswith(help_msg)
 
 
-def test_command():
+def test_command(swhmain):
     @swhmain.command(name='test')
     @click.pass_context
     def swhtest(ctx):
@@ -52,7 +50,7 @@
     assert result.output.strip() == 'Hello SWH!'
 
 
-def test_loglevel_default(caplog):
+def test_loglevel_default(caplog, swhmain):
     @swhmain.command(name='test')
     @click.pass_context
     def swhtest(ctx):
@@ -66,7 +64,7 @@
     assert result.output.strip() == '''Hello SWH!'''
 
 
-def test_loglevel_error(caplog):
+def test_loglevel_error(caplog, swhmain):
     @swhmain.command(name='test')
     @click.pass_context
     def swhtest(ctx):
@@ -79,7 +77,7 @@
     assert result.output.strip() == '''Hello SWH!'''
 
 
-def test_loglevel_debug(caplog):
+def test_loglevel_debug(caplog, swhmain):
     @swhmain.command(name='test')
     @click.pass_context
     def swhtest(ctx):
@@ -120,7 +118,7 @@
     yield str(tmp_path / 'log_config.yml')
 
 
-def test_log_config(caplog, log_config_path):
+def test_log_config(caplog, log_config_path, swhmain):
     @swhmain.command(name='test')
     @click.pass_context
     def swhtest(ctx):
@@ -145,7 +143,7 @@
     ])
 
 
-def test_log_config_log_level_interaction(caplog, log_config_path):
+def test_log_config_log_level_interaction(caplog, log_config_path, swhmain):
     @swhmain.command(name='test')
     @click.pass_context
     def swhtest(ctx):
@@ -170,7 +168,7 @@
     ])
 
 
-def test_aliased_command():
+def test_aliased_command(swhmain):
     @swhmain.command(name='canonical-test')
     @click.pass_context
     def swhtest(ctx):