From 293e1df8b9c57ce48999333e9224f80c5ddb0179 Mon Sep 17 00:00:00 2001
From: Daniel Weschke <daniel.weschke@directbox.de>
Date: Mon, 12 Jan 2026 22:06:40 +0100
Subject: [PATCH] fix vertex

---
 src/fvr/geom2d.py       | 16 ++++++++++-----
 src/fvr/typing.py       |  3 +--
 tests/test_geom2d.py    | 22 +++++++++++++++++++++
 tests/test_structure.py | 43 ++++++++++++++++-------------------------
 4 files changed, 51 insertions(+), 33 deletions(-)
 create mode 100644 tests/test_geom2d.py

diff --git a/src/fvr/geom2d.py b/src/fvr/geom2d.py
index 2c3380b..7534b3d 100644
--- a/src/fvr/geom2d.py
+++ b/src/fvr/geom2d.py
@@ -5,8 +5,9 @@ from fvr.typing import FloatArray
 class Vertex(np.ndarray):
   """Point in 2d space using homogeneous coordinates."""
 
-  def __init__(cls, x=0, y=0):
+  def __new__(cls, x=0, y=0):
     obj = np.asarray([x, y, 1]).view(cls)
+    return obj
 
   @property
   def x(self):
@@ -16,12 +17,16 @@ class Vertex(np.ndarray):
   def y(self):
     return self[1]
 
+  @property
+  def w(self):
+    return self[2]
+
 
 class Polygon:
   r"""Properties of a simple polygon.
   """
 
-  def __init__(self, vertices: FloatArray|str):
+  def __init__(self, vertices: FloatArray | str):
     r"""
     Args:
       vertices: List of points, pair of x and y: ``[[x1, y1], [x2, y2], ...]``
@@ -31,19 +36,20 @@ class Polygon:
     self.vertices = vertices
 
   @staticmethod
-  def str2arr(vertices: str) -> list:
+  def str2arr(vertices: str) -> FloatArray:
     strm = re.match(r'\[.*\]', ''.join(vertices))
     if strm and strm.group():
       return eval(strm.group())
+    return np.array([])
 
   @property
   def area(self) -> float:
     r"""Determine the area of a simple polygon.
 
     Example:
-      >>> polygon([[0, 0], [0, 1], [1, 1], [1, 0]]).area
+      >>> Polygon([[0, 0], [0, 1], [1, 1], [1, 0]]).area
       1.0
-      >>> polygon('[[0, 0], [0, 1], [1, 1], [1, 0]]').area
+      >>> Polygon('[[0, 0], [0, 1], [1, 1], [1, 0]]').area
       1.0
 
     Shoelace formula, Gauss's area formula, surveyor's formula
diff --git a/src/fvr/typing.py b/src/fvr/typing.py
index 1cad337..d5663e7 100644
--- a/src/fvr/typing.py
+++ b/src/fvr/typing.py
@@ -1,4 +1,3 @@
-from collections.abc import Sequence
 import numpy.typing
 
-type FloatArray = Sequence[float] | numpy.typing.NDArray[numpy.float64]
+type FloatArray = numpy.typing.NDArray[numpy.float64]
diff --git a/tests/test_geom2d.py b/tests/test_geom2d.py
new file mode 100644
index 0000000..9333044
--- /dev/null
+++ b/tests/test_geom2d.py
@@ -0,0 +1,22 @@
+"""Test of geom2d module.
+
+"""
+import numpy as np
+import fvr.geom2d
+
+def test_vertex_obj():
+  np.testing.assert_equal(
+    fvr.geom2d.Vertex(1, 2), np.array([1, 2, 1]),
+    'incorrect object after creation')
+
+def test_vertex_x():
+  np.testing.assert_equal(
+    fvr.geom2d.Vertex(1, 2).x, 1, 'incorrect x after creation')
+
+def test_vertex_y():
+  np.testing.assert_equal(
+    fvr.geom2d.Vertex(1, 2).y, 2, 'incorrect y after creation')
+
+def test_vertex_w():
+  np.testing.assert_equal(
+    fvr.geom2d.Vertex(1, 2).w, 1, 'incorrect w after creation')
diff --git a/tests/test_structure.py b/tests/test_structure.py
index b216ce3..629b538 100644
--- a/tests/test_structure.py
+++ b/tests/test_structure.py
@@ -1,53 +1,44 @@
 """Test of structure module.
 
 """
-import unittest
+import pytest
 import fvr.structure
 
-class TestStructureBeam(unittest.TestCase):
-  def setUp(self):
+class TestBeam:
+  @pytest.fixture(autouse=True)
+  def obj(self):
     self.obj = fvr.structure.Beam(1, 2, 3, 4, 5)
 
-  def test_volume(self):
-    self.assertEqual(self.obj.V, 12, 'incorrect volume after creation')
+  def test_beam_volume(self):
+    assert self.obj.V == 12
 
   def test_volume_a(self):
     self.obj.A = 6
-    self.assertEqual(self.obj.V, 24, 'incorrect volume after changing A')
+    assert self.obj.V == 24
 
   def test_volume_l(self):
     self.obj.L = 7
-    self.assertEqual(self.obj.V, 21, 'incorrect volume after changing L')
+    assert self.obj.V == 21
 
   def test_mu(self):
-    self.assertEqual(self.obj.mu, 15, 'incorrect specific mass after creation')
+    assert self.obj.mu == 15
 
   def test_m(self):
-    self.assertEqual(self.obj.m, 60, 'incorrect mass after creation')
+    assert self.obj.m == 60
 
   def test_eigenfrequency(self):
-    self.assertEqual(
-      self.obj.eigenfrequency(1), 0.012770856732837836,
-      'incorrect eigen-frequency after creation')
+    assert self.obj.eigenfrequency(1) == 0.012770856732837836
 
-class TestStructureTubeBuckling(unittest.TestCase):
-  def setUp(self):
+class TestTubeBuckling:
+  @pytest.fixture(autouse=True)
+  def obj(self):
     self.obj = fvr.structure.TubeBuckling(1, 0.2, 3, h=4)
 
   def test_force(self):
-    self.assertEqual(
-      self.obj.force(), 1.8518518518518516,
-      'incorrect buckling force after creation')
+    assert self.obj.force() == 1.8518518518518516
 
   def test_pressure(self):
-    self.assertEqual(
-      self.obj.pressure(), 0.6172839506172838,
-      'incorrect buckling force after creation')
+    assert self.obj.pressure() == 0.6172839506172838
 
   def test_stress(self):
-    self.assertEqual(
-      self.obj.stress(), 0.46296296296296297,
-      'incorrect buckling force after creation')
-
-if __name__ == '__main__':
-  unittest.main()
+    assert self.obj.stress() == 0.46296296296296297