From 4bc5d66060b75e63e88a76c8de2f3511d8033546 Mon Sep 17 00:00:00 2001
From: Juan Nunez-Iglesias <juan.n@unimelb.edu.au>
Date: Wed, 29 Jan 2014 22:50:19 +1100
Subject: [PATCH] Add numerous (14) tests for profile_line()

---
 skimage/measure/tests/test_profile.py | 110 ++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 skimage/measure/tests/test_profile.py

diff --git a/skimage/measure/tests/test_profile.py b/skimage/measure/tests/test_profile.py
new file mode 100644
index 00000000..e911673b
--- /dev/null
+++ b/skimage/measure/tests/test_profile.py
@@ -0,0 +1,110 @@
+from numpy.testing import assert_equal, assert_almost_equal
+import numpy as np
+
+from skimage.measure import profile_line
+
+image = np.arange(100).reshape((10, 10)).astype(np.float)
+
+def test_horizontal_rightward():
+    prof = profile_line(image, (0, 2), (0, 8), order=0)
+    expected_prof = np.arange(2, 9)
+    assert_equal(prof, expected_prof)
+
+
+def test_horizontal_leftward():
+    prof = profile_line(image, (0, 8), (0, 2), order=0)
+    expected_prof = np.arange(8, 1, -1)
+    assert_equal(prof, expected_prof)
+
+
+def test_vertical_downward():
+    prof = profile_line(image, (2, 5), (8, 5), order=0)
+    expected_prof = np.arange(25, 95, 10)
+    assert_equal(prof, expected_prof)
+
+
+def test_vertical_upward():
+    prof = profile_line(image, (8, 5), (2, 5), order=0)
+    expected_prof = np.arange(85, 15, -10)
+    assert_equal(prof, expected_prof)
+
+
+def test_45deg_right_downward():
+    prof = profile_line(image, (2, 2), (8, 8), order=0)
+    expected_prof = np.array([22, 33, 33, 44, 55, 55, 66, 77, 77, 88])
+    # repeats are due to aliasing using nearest neighbor interpolation.
+    # to see this, imagine a diagonal line with markers every unit of
+    # length traversing a checkerboard pattern of squares also of unit
+    # length. Because the line is diagonal, sometimes more than one
+    # marker will fall on the same checkerboard box.
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_45deg_right_downward_interpolated():
+    prof = profile_line(image, (2, 2), (8, 8), order=1)
+    expected_prof = np.linspace(22, 88, 10)
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_45deg_right_upward():
+    prof = profile_line(image, (8, 2), (2, 8), order=1)
+    expected_prof = np.arange(82, 27, -6)
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_45deg_left_upward():
+    prof = profile_line(image, (8, 8), (2, 2), order=1)
+    expected_prof = np.arange(88, 21, -22. / 3)
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_45deg_left_downward():
+    prof = profile_line(image, (2, 8), (8, 2), order=1)
+    expected_prof = np.arange(28, 83, 6)
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_pythagorean_triangle_right_downward():
+    prof = profile_line(image, (1, 1), (7, 9), order=0)
+    expected_prof = np.array([11, 22, 23, 33, 34, 45, 56, 57, 67, 68, 79])
+    assert_equal(prof, expected_prof)
+
+
+def test_pythagorean_triangle_right_downward_interpolated():
+    prof = profile_line(image, (1, 1), (7, 9), order=1)
+    expected_prof = np.linspace(11, 79, 11)
+    assert_almost_equal(prof, expected_prof)
+
+pyth_image = np.zeros((6, 7), np.float)
+line = ((1, 2, 2, 3, 3, 4), (1, 2, 3, 3, 4, 5))
+below = ((2, 2, 3, 4, 4, 5), (0, 1, 2, 3, 4, 4))
+above = ((0, 1, 1, 2, 3, 3), (2, 2, 3, 4, 5, 6))
+pyth_image[line] = 1.8
+pyth_image[below] = 0.6
+pyth_image[above] = 0.6
+
+
+def test_pythagorean_triangle_right_downward_linewidth():
+    prof = profile_line(pyth_image, (1, 1), (4, 5), linewidth=3, order=0)
+    expected_prof = np.ones(6)
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_pythagorean_triangle_right_upward_linewidth():
+    prof = profile_line(pyth_image[::-1, :], (4, 1), (1, 5),
+                        linewidth=3, order=0)
+    expected_prof = np.ones(6)
+    assert_almost_equal(prof, expected_prof)
+
+
+def test_pythagorean_triangle_transpose_left_down_linewidth():
+    prof = profile_line(pyth_image.T[:, ::-1], (1, 4), (5, 1),
+                        linewidth=3, order=0)
+    expected_prof = np.ones(6)
+    assert_almost_equal(prof, expected_prof)
+
+
+if __name__ == "__main__":
+    from numpy.testing import run_module_suite
+    run_module_suite()
+