Surface subclass: plane, and tests

elastica/surface/__init__.py

@@ -1,2 +1,3 @@
 __doc__ = """Surface classes"""
 from elastica.surface.surface_base import SurfaceBase
+from elastica.surface.plane import Plane

elastica/surface/plane.py

@@ -0,0 +1,31 @@
+__doc__ = """plane surface class"""
+
+from elastica.surface.surface_base import SurfaceBase
+import numpy as np
+from numpy.testing import assert_allclose
+from elastica.utils import Tolerance
+
+
+class Plane(SurfaceBase):
+    def __init__(self, plane_origin: np.ndarray, plane_normal: np.ndarray):
+        """
+        Plane surface initializer.
+
+        Parameters
+        ----------
+        plane_origin: np.ndarray
+            Origin of the plane.
+            Expect (3,1)-shaped array.
+        plane_normal: np.ndarray
+            The normal vector of the plane, must be normalized.
+            Expect (3,1)-shaped array.
+        """
+
+        assert_allclose(
+            np.linalg.norm(plane_normal),
+            1,
+            atol=Tolerance.atol(),
+            err_msg="plane normal is not a unit vector",
+        )
+        self.normal = np.asarray(plane_normal).reshape(3)
+        self.origin = np.asarray(plane_origin).reshape(3, 1)

tests/test_surface/test_plane.py

@@ -0,0 +1,41 @@
+__doc__ = """Tests for plane surface class"""
+import numpy as np
+from numpy.testing import assert_allclose
+from elastica.utils import Tolerance
+from elastica.surface import Plane
+import pytest
+
+
+# tests Initialisation of plane
+def test_plane_initialization():
+    """
+    This test case is for testing initialization of rigid sphere and it checks the
+    validity of the members of sphere class.
+
+    Returns
+    -------
+
+    """
+    # setting up test params
+    plane_origin = np.random.rand(3).reshape(3, 1)
+    plane_normal_direction = np.random.rand(3).reshape(3)
+    plane_normal = plane_normal_direction / np.linalg.norm(plane_normal_direction)
+
+    test_plane = Plane(plane_origin, plane_normal)
+    # checking plane origin
+    assert_allclose(
+        test_plane.origin,
+        plane_origin,
+        atol=Tolerance.atol(),
+    )
+
+    # checking plane normal
+    assert_allclose(test_plane.normal, plane_normal, atol=Tolerance.atol())
+
+    # check unnormalized error message
+    invalid_plane_normal = np.zeros(
+        3,
+    )
+    with pytest.raises(AssertionError) as excinfo:
+        test_plane = Plane(plane_origin, invalid_plane_normal)
+    assert "plane normal is not a unit vector" in str(excinfo.value)