keyword-tests

name	keyword-tests
description	> Use when this capability is needed.

Keyword Tests Skill

Test Locations

Path	Purpose
tests/	All pytest tests
tests/testfiles/keywords/	Reference .k files and reference_string.py
tests/testfiles/initial/	Initial deck .k files used as fixtures
tests/testfiles/output/	Expected output files for comparison
tests/test_codegen/	Codegen-only — do NOT run with normal pytest

Running Tests

Use whichever Python environment has PyDyna installed. The commands below use python as a placeholder — substitute your actual interpreter or prefix as needed.

Tip: Create .github/copilot-instructions.md (already gitignored) to tell the agent which Python environment to use. For example:

Use `uv run --no-project python` when running Python commands in this repo.

or

Use `/path/to/my/venv/bin/python` when running Python commands in this repo.

# Run all non-run tests (standard)
python -m pytest tests/ -v

# Run a specific file
python -m pytest tests/test_keywords.py -v

# Run a specific test
python -m pytest tests/test_card.py::test_load_card_errors -v

# Run with -m run (requires LS-DYNA environment)
python -m pytest tests/ -v -m run

Key Fixtures (from tests/conftest.py)

Fixture	Type	Use
string_utils	StringUtils	Convert a string to a readable io.StringIO buffer via .as_buffer(s)
file_utils	FileUtils	Read/compare files in testfiles/; compare output with .compare_string_with_file(output, ref_file)
ref_string	module	Loads testfiles/keywords/reference_string.py; access expected strings as attributes
runner	DynaRunner	Run LS-DYNA simulations; only used with @pytest.mark.run tests
resolve_standard_path	str	Path to testfiles/standard/
resolve_output_path	str	Path to testfiles/output/
*_initialfile	str	Paths to specific initial .k files (e.g. mech_initialfile, icfd_initialfile)

The run Marker

Tests that require a live LS-DYNA installation must be marked with @pytest.mark.run:

@pytest.mark.run
def test_something_that_needs_lsdyna(runner):
    ...

• Skipped by default when running pytest tests/ without -m run
• Enabled only with pytest -m run in environments with LS-DYNA available
• Do NOT use this marker for pure unit/rendering tests

Writing a Keyword Rendering Test

Pattern: instantiate keyword, set fields, call .write(), compare to expected string.

from ansys.dyna.core import keywords as kwd
import pytest

def test_my_keyword_renders(file_utils):
    k = kwd.MyKeyword()
    k.some_field = 42
    output = k.write()
    file_utils.compare_string_with_file(output, "my_keyword_reference.k")

Then create tests/testfiles/keywords/my_keyword_reference.k with the expected output.

Trailing whitespace: LS-DYNA fixed-width fields are padded to their full column width, so reference .k files will contain trailing spaces on data lines. Do not strip or trim whitespace in these files — doing so will cause tests to fail.

Writing a Keyword Parsing Test

Pattern: use string_utils.as_buffer() or load a .k file via file_utils, call deck.loads() or card .read().

from ansys.dyna.core import Deck, keywords as kwd

def test_my_keyword_parses(string_utils):
    input_str = "*MY_KEYWORD\n        42\n*END\n"
    deck = Deck()
    deck.loads(input_str)
    kw = deck.get(kwd.MyKeyword)
    assert kw is not None
    assert kw.some_field == 42

Writing a Card-Level Test

Use Card.from_field_schemas for low-level card tests:

from ansys.dyna.core.lib.card import Card
from ansys.dyna.core.lib.field_schema import FieldSchema

def test_card_reads_correctly(string_utils):
    field_schemas = (
        FieldSchema("foo", int, 0, 10, None),
        FieldSchema("bar", float, 10, 10, None),
    )
    card = Card.from_field_schemas(field_schemas)
    result = card.read(string_utils.as_buffer("        42     3.14"))
    assert card.foo == 42

Adding a Reference String

For tests using ref_string, add the expected value as an attribute in tests/testfiles/keywords/reference_string.py:

# In reference_string.py
test_my_keyword_output = "*MY_KEYWORD\n        42\n"

Trailing whitespace: String values in reference_string.py may contain trailing spaces within lines — this is intentional. LS-DYNA fixed-width fields are padded to their full column width and the output reflects that exactly. Do not strip these strings.

Then in the test:

def test_my_keyword(ref_string):
    k = kwd.MyKeyword()
    k.some_field = 42
    assert k.write() == ref_string.test_my_keyword_output

Common Pitfalls

• Do not collect tests/test_codegen/ — these are for the codegen validation system only, not for testing PyDyna behavior
• Trailing whitespace is intentional — reference .k files and strings in reference_string.py contain trailing spaces on data lines because LS-DYNA fields are fixed-width padded. Never strip or auto-trim whitespace in these files.
• Line endings: file_utils normalizes \r\n → \n; always use \n in reference files
• write() output includes trailing newline — include it in reference strings
• Import: use from ansys.dyna.core import keywords as kwd, not direct module imports
• Format type: some tests require format_type.long — check with kwd.MyKeyword(format=format_type.long)

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Source: ansys/pydyna — distributed by TomeVault.