Add structural calculation worksheets

Collection of engineering calculation projects (Python + Typst), each with
input, calc script, tests, results, and generated PDF where available.

wood-stud-column/test_wood_stud_column.py

@@ -0,0 +1,65 @@
+from pathlib import Path
+import importlib.util
+import json
+import subprocess
+import sys
+
+import pytest
+import yaml
+
+HERE = Path(__file__).resolve().parent
+spec = importlib.util.spec_from_file_location("wood_stud_column_calc", HERE / "calc.py")
+assert spec is not None and spec.loader is not None
+module = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(module)
+
+
+def result():
+    with (HERE / "input.yaml").open(encoding="utf-8") as handle:
+        return module.compute(yaml.safe_load(handle))
+
+
+def test_typst_loads_match_checked_inputs():
+    subprocess.run([sys.executable, str(HERE / "calc.py")], check=True, cwd=HERE.parents[1])
+    query = subprocess.run(
+        [
+            "typst", "eval", "query(<wood-stud-column-loads>)", "--root", ".",
+            "--in", "calcs/wood-stud-column/beam.typ", "--format", "json",
+        ],
+        check=True,
+        capture_output=True,
+        text=True,
+        cwd=HERE.parents[1],
+    )
+    published = json.loads(query.stdout)
+    assert len(published) == 1
+    derived = published[0]["value"]
+    values = result()["values"]
+    assert derived["P_lbf"] == pytest.approx(values["P_lbf"], abs=0.001)
+    assert derived["A_in2"] == pytest.approx(values["A_in2"], abs=0.001)
+
+
+def test_ground_truth_column_stability():
+    output = result()
+    values = output["values"]
+    assert values["A_in2"] == pytest.approx(5.25)
+    assert values["Le_in"] == pytest.approx(72.0)
+    assert values["Le_d_weak"] == pytest.approx(48.0, abs=0.01)
+    assert values["FcE_weak_psi"] == pytest.approx(181.9, abs=0.5)
+    assert values["Cp_weak"] == pytest.approx(0.107, abs=0.003)
+    assert values["Cp_strong"] == pytest.approx(0.497, abs=0.005)
+    assert values["Fc_prime_psi"] == pytest.approx(177.6, abs=0.5)
+    assert values["Pa_lbf"] == pytest.approx(932.0, abs=3.0)
+    assert output["checks"]["axial"]["ok"] is True
+
+
+def test_cli_can_write_json_to_stdout():
+    completed = subprocess.run(
+        [sys.executable, str(HERE / "calc.py"), "--input", str(HERE / "input.yaml"), "--stdout"],
+        check=True,
+        capture_output=True,
+        text=True,
+    )
+    output = json.loads(completed.stdout)
+    assert output["values"]["P_lbf"] == pytest.approx(400)
+    assert completed.stderr == ""