Feat/Split WL and Layer + Feat/Add Schöttner E(ρ) elasticity + Chore/Test Suite to Pytest

.github/workflows/tests.yml

@@ -23,7 +23,7 @@ jobs:
           version: "latest"
 
       - name: Install dependencies
-        run: uv sync
+        run: uv sync --extra dev
 
       - name: Run tests
-        run: uv run python tests/run_tests.py
+        run: uv run pytest

.gitignore

@@ -59,5 +59,6 @@ old*
 
 .weac-reference/
 
-# Folder for development and local testing
-dev/
+# Folders for development and local testing
+dev/
+todo/

README.md

@@ -1,7 +1,7 @@
+<!-- markdownlint-disable MD033 MD009 MD053 -->
 <!-- LOGO AND TITLE-->
 <!-- <p align="right"><img src="https://github.com/2phi/weac/raw/main/img/logo.png" alt="Logo" width="80" height="80"></p> -->
 
-
 <h1 align="center">
   <br>
   <img src="https://github.com/2phi/weac/raw/main/img/logo.png" alt="WEAC" width="120">
@@ -84,18 +84,19 @@ WEAC implements closed-form analytical models for the [mechanical analysis of dr
 <img src="https://github.com/2phi/weac/raw/main/img/systems.png" alt="Systems" width="500"/>
 
 Cite the repository as:
-```
+
+```text
 Rosendahl, P. L., Schneider, J., & Weissgraeber, P. (2022). Weak Layer Anticrack Nucleation Model (WEAC). Zenodo. https://doi.org/10.5281/zenodo.5773113
 ```
 
 Read the [📄 white paper](https://doi.org/10.5194/tc-17-1475-2023) for model derivations, illustrations, dimensions, material properties, and kinematics:
 
-- Weißgraeber, P. & Rosendahl, P. L. (2023). A closed-form model for layered snow slabs. The Cryosphere, 17(4), 1475–1496. https://doi.org/10.5194/tc-17-1475-2023
+- Weißgraeber, P. & Rosendahl, P. L. (2023). A closed-form model for layered snow slabs. The Cryosphere, 17(4), 1475–1496. <https://doi.org/10.5194/tc-17-1475-2023>
 
 For more background info, please refer to the companion papers:
 
-- Rosendahl, P. L. & Weißgraeber, P. (2020). Modeling snow slab avalanches caused by weak-layer failure – Part 1: Slabs on compliant and collapsible weak layers. The Cryosphere, 14(1), 115–130. https://doi.org/10.5194/tc-14-115-2020
-- Rosendahl, P. L. & Weißgraeber, P. (2020). Modeling snow slab avalanches caused by weak-layer failure – Part 2: Coupled mixed-mode criterion for skier-triggered anticracks. The Cryosphere, 14(1), 131–145. https://doi.org/10.5194/tc-14-131-2020
+- Rosendahl, P. L. & Weißgraeber, P. (2020). Modeling snow slab avalanches caused by weak-layer failure – Part 1: Slabs on compliant and collapsible weak layers. The Cryosphere, 14(1), 115–130. <https://doi.org/10.5194/tc-14-115-2020>
+- Rosendahl, P. L. & Weißgraeber, P. (2020). Modeling snow slab avalanches caused by weak-layer failure – Part 2: Coupled mixed-mode criterion for skier-triggered anticracks. The Cryosphere, 14(1), 131–145. <https://doi.org/10.5194/tc-14-131-2020>
 
 Written in [🐍 Python](https://www.python.org) and built with [💻 Visual Studio Code](https://code.visualstudio.com), [🐙 GitKraken](https://www.gitkraken.com), and [🪐 Jupyter](https://jupyter.org). Note that [release v1.0](https://github.com/2phi/weac/releases/tag/v1.0.0) was written and built in [🌋 MATLAB](https://www.mathworks.com/products/matlab.html).
 
@@ -105,19 +106,21 @@ Written in [🐍 Python](https://www.python.org) and built with [💻 Visual Stu
 [![Atom](https://img.shields.io/badge/Atom-498b60.svg?style=flat-square&logo=atom&logoColor=white&label&labelColor=gray)](https://atom.io)
 [![GitKraken](https://img.shields.io/badge/GitKraken-179287.svg?style=flat-square&logo=gitkraken&logoColor=white&label&labelColor=gray)](https://www.gitkraken.com) -->
 
-
-
 <!-- INSTALLATION -->
 ## Installation
 
 Install globally using the `pip` Package Installer for Python
+
 ```sh
 pip install -U weac
 ```
+
 or clone the repo
+
 ```sh
 git clone https://github.com/2phi/weac
 ```
+
 for local use.
 
 Needs (runtime dependencies are declared in [pyproject.toml](https://github.com/2phi/weac/blob/main/pyproject.toml)):
@@ -129,7 +132,6 @@ Needs (runtime dependencies are declared in [pyproject.toml](https://github.com/
 - [Pydantic](https://docs.pydantic.dev/latest/) ≥ 2.11.7
 - [Snowpylot](https://github.com/connellymk/snowpylot) ≥ 1.1.3
 
-
 <!-- DEVELOPMENT SETUP -->
 ## Development Setup
 
@@ -173,10 +175,6 @@ source .venv/bin/activate  # On Windows: .venv\Scripts\activate
 Run the test suite using uv:
 
 ```bash
-# Run all tests
-uv run python tests/run_tests.py
-
-# Or use pytest directly (if installed)
 uv run pytest
 ```
 
@@ -387,6 +385,12 @@ See the [open issues](https://github.com/2phi/weac/issues) for a list of propose
 
 ## Release history
 
+### v3.2
+
+- Split `Layer` and `WeakLayer` into separate component models
+- Weak-layer Young's modulus from Schöttner FC&DH density law (`E_method="schottner_fc_dh"`)
+- Lowered weak-layer preset densities to 100/150/200 kg/m³ (within the Schöttner ≤250 kg/m³ range)
+
 ### v3.0
 
 - Refactored the codebase for improved structure and maintainability
@@ -468,6 +472,7 @@ See the [open issues](https://github.com/2phi/weac/issues) for a list of propose
 
 <!-- WORKFLOWS -->
 ## Workflows
+
 [![Publish Python 🐍 releases 📦 to PyPI ](https://github.com/2phi/weac/actions/workflows/release.yml/badge.svg)](https://github.com/2phi/weac/actions/workflows/release.yml)<br>
 [![Build and publish Sphinx 🪬 documentation ](https://github.com/2phi/weac/actions/workflows/docs.yml/badge.svg)](https://github.com/2phi/weac/actions/workflows/docs.yml)
 
@@ -489,14 +494,10 @@ Under the following terms:
 
 - **ShareAlike** — If you remix, transform, or build upon the material, you must distribute your contributions under the [same license](https://creativecommons.org/licenses/by-nc-sa/4.0/?ref=chooser-v1#ref-same-license) as the original.
 
-
-
 <!-- CONTACT -->
 ## Contact
 
-E-mail: mail@2phi.de · Web: https://2phi.de · Project Link: [https://github.com/2phi/weac](https://github.com/2phi/weac) · Project DOI: [http://dx.doi.org/10.5281/zenodo.5773113](http://dx.doi.org/10.5281/zenodo.5773113)
-
-
+E-mail: <mail@2phi.de> · Web: <https://2phi.de> · Project Link: [https://github.com/2phi/weac](https://github.com/2phi/weac) · Project DOI: [http://dx.doi.org/10.5281/zenodo.5773113](http://dx.doi.org/10.5281/zenodo.5773113)
 
 <!-- MARKDOWN LINKS & IMAGES -->
 <!-- https://www.markdownguide.org/basic-syntax/#reference-style-links -->
@@ -528,4 +529,4 @@ E-mail: mail@2phi.de · Web: https://2phi.de · Project Link: [https://github.co
 [pypi-url]: https://pypi.org/project/weac/
 [release-url]: https://github.com/2phi/weac/releases
 [weac-url]: https://github.com/2phi/weac/
-[doi-url]: https://zenodo.org/badge/latestdoi/203163531
+[doi-url]: https://zenodo.org/badge/latestdoi/203163531

TODO.md

@@ -10,8 +10,17 @@
 
 ## Minor
 
-- [ ] Swap to Pytest from Unittest
-- [ ] resolve fracture criterion also when lower than strength criterion
+- [ ] Free-end coupled criterion for finite lab specimens (e.g. 1 m slab): `CriteriaEvaluator` currently requires `system_type="skier"` with infinite-end BCs; support free-end (PST-style) mid-load CC without approximating ends as infinite
+- [ ] Per-segment effective out-of-plane load length `l_eff` [mm] on `Segment`
+  - Needed for: converting a point mass `m` [kg] into the unit-width line-load jump used by the solver when the load does not span the global default ski length. Today `get_skier_point_load` and `Scenario._setup_scenario` always divide by `constants.LSKI_MM` (1000 mm), so short skis, long skis, or a narrow out-of-plane contact (e.g. a cube’s depth) cannot be represented correctly—especially when sample width `b` differs from 1000 mm.
+  - Formula: `F [N/mm] = 1e-3 * m * G_MM_S2 / l_eff` (same as today with `l_eff = LSKI_MM`). Smaller `l_eff` → larger intensity for the same mass.
+  - Requires:
+    - Add optional `Segment.l_eff: float` (default `LSKI_MM`) applying to the mass at that segment’s right edge (`m`).
+    - Thread `l_eff` through `get_skier_point_load(m, l_eff=…)` (or replace it), `Scenario.fi` assembly, and both `UnknownConstantsSolver` / `GeneralizedUnknownConstantsSolver` so no path still hardcodes `LSKI_MM`.
+    - Keep backward compatibility: omit/`None` → `LSKI_MM`; existing skier/CC tests unchanged.
+    - Document interaction with slab width `b`: `l_eff` is the out-of-plane contact extent of *this* load; clipping to `min(l_eff, b)` may be needed when the object is wider than the specimen.
+    - Unit tests: same `m`, two `l_eff` values → interface load scales as `1/l_eff`; default `l_eff` matches legacy `LSKI_MM` results.
+  - Out of scope for this item: finite along-slope contact length (patch/`qs`); full `AppliedLoad` objects; tilted-cube contact modes.
 - [ ] Florian CriterionEvaluator: clarify and fix damping behavior (find_minimum_force / evaluate_coupled_criterion)
   - Expected behavior
     - find_minimum_force: compute the critical skier weight w* [kg] such that max(stress_envelope) == 1 within tolerance_stress. This solver should not apply damping; it must return the numerically precise root of residual(weight) = max(stress_envelope) - 1 using a bracketed method and finite tolerances.
@@ -133,7 +142,6 @@
 - [ ] Make rasterize_solution smarter (iterative convergence)
 - [ ] SNOWPACK Parser
 - [ ] SMP Parser
-- [ ] Build Tests: Integration -> Pure
 
 ## Patch
 

docs/sphinx/weac.components.rst

@@ -13,6 +13,7 @@ Submodules
    weac.components.model_input
    weac.components.scenario_config
    weac.components.segment
+   weac.components.weak_layer
 
 Module contents
 ---------------

docs/sphinx/weac.components.weak_layer.rst

@@ -0,0 +1,7 @@
+weac.components.weak_layer module
+=================================
+
+.. automodule:: weac.components.weak_layer
+   :members:
+   :show-inheritance:
+   :undoc-members:

pyproject.toml

@@ -72,6 +72,9 @@ dev = [
     "black>=24.4.0",
     "isort>=5.13.0",
 
+    # Testing
+    "pytest>=8",
+
     # Versioning helper matching [tool.bumpversion]
     "bump-my-version", # e.g. bump-my-version bump patch
 ]
@@ -85,6 +88,9 @@ where = ["src"]
 # [tool.uv.sources]
 # snowpylot = { path = "../snowpylot", editable = true }
 
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+
 [tool.ruff.lint]
 ignore = ["E741"]
 

src/weac/analysis/plotter.py

@@ -24,7 +24,7 @@
 )
 
 # Module imports
-from weac.components.layer import WeakLayer
+from weac.components.weak_layer import WeakLayer
 from weac.core.scenario import Scenario
 from weac.core.slab import Slab
 from weac.core.system_model import SystemModel

src/weac/components/__init__.py

@@ -4,7 +4,7 @@
 
 from .config import Config
 from .criteria_config import CriteriaConfig
-from .layer import Layer, WeakLayer
+from .layer import Layer
 from .model_input import ModelInput
 from .presets import (
     LESS_WEAK_LAYER,
@@ -15,6 +15,7 @@
 )
 from .scenario_config import ScenarioConfig, SystemType, TouchdownMode
 from .segment import Segment
+from .weak_layer import WeakLayer
 
 __all__ = [
     "Config",