select preset with cli arg

tests/core/pyspec/README.md

@@ -57,21 +57,22 @@ Caveats:
 
 Full test usage, with explicit configuration for illustration of options usage:
 ```shell
-(venv) python -m pytest --config=minimal eth2spec
+(venv) python -m pytest --preset=minimal eth2spec
 ```
 
 Or, to run a specific test file, specify the full path:
 ```shell
-(venv) python -m pytest --config=minimal ./eth2spec/test/phase0/block_processing/test_process_attestation.py
+(venv) python -m pytest --preset=minimal ./eth2spec/test/phase0/block_processing/test_process_attestation.py
 ```
 
 Or, to run a specific test function (specify the `eth2spec` module, or the script path if the keyword is ambiguous):
 ```shell
-(venv) python -m pytest --config=minimal -k test_success_multi_proposer_index_iterations eth2spec
+(venv) python -m pytest --preset=minimal -k test_success_multi_proposer_index_iterations eth2spec
 ```
 
 Options:
-- `--config`, to change the config. Defaults to `minimal`, can be set to `mainnet`, or other configs from the configs directory.
+- `--preset`, to change the preset (compile-time configurables). Defaults to `minimal`, can be set to `mainnet`.
+  Use `@spec_configured_state_test({config here...}` to override runtime configurables on a per-test basis.
 - `--disable-bls`, to disable BLS (only for tests that can run without)
 - `--bls-type`, `milagro` or `py_ecc` (default)
 

tests/core/pyspec/eth2spec/test/conftest.py

@@ -41,9 +41,7 @@ def pytest_addoption(parser):
 
 @fixture(autouse=True)
 def preset(request):
-    # TODO: apply to tests, see context.py 'with_presets'
-    preset_flag_value = request.config.getoption("--preset")
-    print("preset:", preset_flag_value)
+    context.DEFAULT_TEST_PRESET = request.config.getoption("--preset")
 
 
 @fixture(autouse=True)

tests/core/pyspec/eth2spec/test/context.py

@@ -19,6 +19,9 @@ from typing import Any, Callable, Sequence, TypedDict, Protocol, Dict
 
 from lru import LRU
 
+# Without pytest CLI arg or pyspec-test-generator 'preset' argument, this will be the config to apply.
+DEFAULT_TEST_PRESET = MINIMAL
+
 
 # TODO: currently phases are defined as python modules.
 # It would be better if they would be more well-defined interfaces for stronger typing.
@@ -339,7 +342,7 @@ def with_phases(phases, other_phases=None):
             if other_phases is not None:
                 available_phases |= set(other_phases)
 
-            preset_name = MINIMAL
+            preset_name = DEFAULT_TEST_PRESET
             if 'preset' in kw:
                 preset_name = kw.pop('preset')
             targets = spec_targets[preset_name]