last example of chapter 9: classes/vector_v5.py

classes/test_vector_spherical.py

@@ -0,0 +1,37 @@
+"""
+Test spherical coordinates in ``Vector`` class
+"""
+
+import sys
+from vector_v5 import Vector
+
+FIXTURE = 'spherical-coordinates.txt'
+EPSILON = 10**-8
+
+def parse_float_cells(cells):
+    floats = []
+    for cell in cells:
+        try:
+            floats.append(float(cell))
+        except ValueError:
+            continue
+    return floats
+
+def load_fixture(verbose=False):
+    with open(FIXTURE, encoding='utf8') as text:
+        for line in text:
+            if line.startswith('#'):  # comment line
+                continue
+            cells = line.split('\t')
+            cartesian = parse_float_cells(cells[:5])
+            spherical = parse_float_cells(cells[5:])
+            v = Vector(cartesian)
+            if verbose:
+                print(repr(v), '\t->', spherical)
+            diff = abs(abs(v) - spherical[0])
+            assert diff < EPSILON, 'expected {}, got {}'.format(spherical[0], abs(v))
+            assert all(abs(av - af) < EPSILON for av, af in zip(v.angles(), spherical[1:])), (
+                'expected {}, got {}'.format(spherical[1:], list(v.angles())))
+
+if __name__=='__main__':
+    load_fixture('-v' in sys.argv)