[Feature] Make NFC_Reader_index default 0

[rquidute]

What Changed

Adds support for automatically defaulting NFC_Reader_index to 0 when not explicitly provided in test_parameters for NFC pairing modes (nfc-wifi and nfc-thread). This removes the need for users to always specify the reader index when a single NFC reader is in use.

Motivation

The SDK runner requires NFC_Reader_index to be present in global_test_params when using NFC commissioning. Most setups use a single NFC reader (index 0), so requiring users to always pass this parameter explicitly adds unnecessary friction. This feature makes index 0 the implicit default, allowing NFC tests to run out of the box without extra configuration.

Impact

• No breaking changes. Users who already pass "int-arg": "NFC_Reader_index:" in test_parameters are unaffected — their value is used as-is.
• NFC pairing mode tests now work without requiring NFC_Reader_index to be explicitly configured.

Changes

• test_collections/matter/sdk_tests/support/python_testing/models/utils.py

  • In generate_command_arguments(), when the pairing mode is an NFC mode, checks whether NFC_Reader_index is already present in the int-arg test parameter.
  • If absent, injects NFC_Reader_index:0 into test_parameters["int-arg"] so it flows through the existing _SPLIT_ARGS loop as a single --int-arg block.
  • If already present (user explicitly set a value), the existing value is left untouched.

• test_collections/matter/sdk_tests/support/tests/python_tests/test_utils.py

  • Updated 3 existing NFC test assertions to include --int-arg / NFC_Reader_index:0 at the end of the expected argument list.
  • Added 5 new parametrized test functions (covering both nfc-wifi and nfc-thread, totalling 9 new test cases):
    • Defaults to 0 when test_parameters is None
    • Defaults to 0 when test_parameters exists but int-arg has no NFC_Reader_index
    • Uses the explicit value when NFC_Reader_index is already in int-arg
    • Does not duplicate NFC_Reader_index when already present
    • Does not inject NFC_Reader_index for non-NFC pairing modes

Related Issue

project-chip/certification-tool#980

Testing

• Unit tests added and all passing

• Run a test execution with no NFC_Reader_index informed and the TH send command with --int-arg NFC_Reader_index:0

[gemini-code-assist]

Code Review

This pull request updates the handling of NFC pairing modes by making discriminator and setup code optional and injecting a default NFC reader index into command arguments. Feedback highlights a potential crash and side-effect in the parameter injection logic, a missing f-string prefix in a validation error message, and an inconsistency where the reader index injection is missing from performance tests.