[PATCH v3 07/10] tests/arg_parser: add test for lazy loading of bb.ui modules

["Chris Laplante" <chris.laplante@agilent.com>]

Ensures bb.ui modules are loaded lazily during construction
of the 'bitbake' argument parser.

Signed-off-by: Chris Laplante <chris.laplante@agilent.com>
---
 lib/bb/main.py             |  5 ++++-
 lib/bb/tests/arg_parser.py | 18 +++++++++++++++---
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/lib/bb/main.py b/lib/bb/main.py
index ccb844bb..f8a19bc3 100755
--- a/lib/bb/main.py
+++ b/lib/bb/main.py
@@ -98,12 +98,15 @@ class LazyUiChoices:
     """
     def __init__(self):
         # map module name => imported module
-        self._modules = {}
+        self._modules = None
 
     def _lazy_load_modules(self):
         if not self._modules:
             self._modules = {module.__name__.split(".")[-1]: module for module in load_extension_modules(bb.ui, "main")}
 
+    @property
+    def has_loaded_modules(self): return self._modules is not None
+
     def __iter__(self):
         self._lazy_load_modules()
         yield from self._modules.keys()
diff --git a/lib/bb/tests/arg_parser.py b/lib/bb/tests/arg_parser.py
index fd46fe8c..be2d86fa 100644
--- a/lib/bb/tests/arg_parser.py
+++ b/lib/bb/tests/arg_parser.py
@@ -7,12 +7,11 @@
 # SPDX-License-Identifier: MIT
 #
 
+import collections
 import shlex
 import unittest
-import collections
-
 
-from bb.main import create_bitbake_parser, BitBakeConfigParameters
+from bb.main import create_bitbake_parser, BitBakeConfigParameters, LazyUiChoices
 
 ParseResult = collections.namedtuple("ParseResult", ("options", "targets"))
 
@@ -41,3 +40,16 @@ class ArgParserTests(unittest.TestCase):
             res = self._parse_helper(arg_str)
             self.assertListEqual(res.targets, ["world"])
             self.assertListEqual(res.options.dump_signatures, ["none"])
+
+    def test_lazy_module_loading(self):
+        # This test ensures that the bb.ui modules weren't loaded immediately upon creation of the arg parser
+
+        # Find the UI action
+        ui_actions = [action for action in self._parser._actions if action.dest == "ui"]
+        if len(ui_actions) > 1:
+            self.fail("Found more than one 'ui' action in the argument parser?")
+        self.assertEqual(len(ui_actions), 1, "Didn't find the 'ui' action in the argument parser?")
+
+        ui_action = ui_actions[0]
+        self.assertIs(type(ui_action.type), LazyUiChoices, "'ui' action has wrong type")
+        self.assertFalse(ui_action.type.has_loaded_modules, "Creation of the arg parser loaded the bb.ui modules")
-- 
2.17.1