Fix install requirements of disabled checks

tests/unit/test_steps_prepare.py

@@ -1,7 +1,16 @@
+import shutil
+import tempfile
+from typing import TYPE_CHECKING
 from unittest.mock import MagicMock
 
 from tmt.base.core import DependencySimple
 from tmt.steps.prepare.install import PrepareInstall
+from tmt.utils import Path
+
+if TYPE_CHECKING:
+    from tests import RunTmt
+
+DISABLED_CHECK_DATA = Path(__file__).resolve().parent / 'disabled_check_data'
 
 
 def test_debuginfo(root_logger):
@@ -35,3 +44,21 @@ def test_debuginfo(root_logger):
         "grep",
         "elfutils-debuginfod",
     ]
+
+
+def test_disabled_check_skips_essential_requires(run_tmt: 'RunTmt'):
+    """
+    Disabled check must not contribute its essential requirements
+    to the prepare step's package list.
+    """
+
+    tmp = tempfile.mkdtemp()
+    result = run_tmt(
+        '--feeling-safe', '--root', str(DISABLED_CHECK_DATA),
+        'run', '-i', tmp, '-vvv',
+        'plan', '--name', '/disabled-only',
+    )
+    shutil.rmtree(tmp)
+
+    assert result.exit_code == 0
+    assert '/usr/bin/dmesg' not in result.output

tmt/steps/execute/upgrade.py

@@ -500,6 +500,8 @@ def _perform_upgrade(self, guest: tmt.guest.Guest, logger: tmt.log.Logger) -> No
                 required_packages += test.test_framework.get_requirements(test, self._logger)
 
                 for check in test.check:
+                    if not check.enabled:
+                        continue
                     required_packages += check.plugin.essential_requires(guest, test, self._logger)
 
             self._install_dependencies(guest, required_packages)

tmt/steps/prepare/__init__.py

@@ -285,6 +285,8 @@ def go(self, force: bool = False) -> None:
                 )
 
                 for check in test.check:
+                    if not check.enabled:
+                        continue
                     collected_requires[guest].dependencies += check.plugin.essential_requires(
                         guest, test, self._logger
                     )

tmt/steps/prepare/distgit.py

@@ -336,6 +336,8 @@ def go(
                     collected_requires += test.test_framework.get_requirements(test, self._logger)
 
                     for check in test.check:
+                        if not check.enabled:
+                            continue
                         collected_requires += check.plugin.essential_requires(
                             guest, test, self._logger
                         )