test(cmakev2): add pytest scripts for cmakev2 build system examples

Add pytest test coverage for cmakev2 build system examples that had
none.

CMakeLists.txt fixes required to enable testing:

conditional_component and plugins: added idf_build_generate_flasher_args()
since these use the low-level build API (idf_build_executable /
idf_flash_binary) which unlike idf_project_default() does not call it
automatically. Without it, flasher_args.json was missing from the build
output and pytest-embedded could not initialize the DUT.

multi_binary: both app1 and app2 were registered in the global flash
target via idf_flash_binary(...FLASH), creating a duplicate key at offset
0x10000 in the flasher_args.json generator expression and preventing the
file from being generated. Fixed by removing FLASH from app2's call so
only app1 is registered in the global flash target. idf_build_generate_flasher_args()
now produces a valid flasher_args.json with app1 as the default app binary.
The test patches the binary path to app2.bin when testing the second app.

examples/build_system/cmakev2/features/plugins/CMakeLists.txt

@@ -28,7 +28,8 @@ idf_check_binary_size(${CMAKE_PROJECT_NAME}_binary)
 # Create app target
 add_custom_target(app ALL DEPENDS ${CMAKE_PROJECT_NAME}_binary)
 
-# Generate metadata
+# Generate flasher_args.json and metadata
+idf_build_generate_flasher_args()
 idf_build_generate_metadata(BINARY ${CMAKE_PROJECT_NAME}_binary)
 
 # Create other utility targets

examples/build_system/cmakev2/features/plugins/pytest_cmakev2_plugins.py

@@ -0,0 +1,31 @@
+# SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: CC0-1.0
+import textwrap
+
+import pytest
+from pytest_embedded import Dut
+from pytest_embedded_idf.utils import idf_parametrize
+
+
+@pytest.mark.generic
+@idf_parametrize('target', ['esp32', 'esp32c3'], indirect=['target'])
+def test_cmakev2_plugins(dut: Dut) -> None:
+    log_text = textwrap.dedent(r"""
+        Hello plugin performing self-registration...
+        Successfully registered plugin 'Hello'
+        Nihao plugin performing self-registration...
+        Successfully registered plugin 'Nihao'
+        main_task: Calling app_main()
+        List of plugins:
+        - Plugin 'Hello'
+        - Plugin 'Nihao'
+        Calling greet function of plugin 'Hello'...
+        Hello, World!
+        Done with greet function of plugin 'Hello'.
+        Calling greet function of plugin 'Nihao'...
+        你好 World!
+        Done with greet function of plugin 'Nihao'.
+    """).strip('\n')
+
+    for line in log_text.split('\n'):
+        dut.expect_exact(line.encode('utf-8'))