Added exception and unittest for dist_mat_to_vec of analysis/psa.py (Part of #597)

testsuite/MDAnalysisTests/analysis/test_psa.py

@@ -26,7 +26,7 @@
 
 from numpy.testing import (TestCase, dec, assert_array_less,
                            assert_array_almost_equal, assert_,
-                           assert_almost_equal)
+                           assert_almost_equal, assert_equal)
 import numpy as np
 
 from MDAnalysisTests.datafiles import PSF, DCD, DCD2
@@ -93,6 +93,15 @@ def test_dendrogram_produced(self):
         err_msg = "Dendrogram dictionary object was not produced"
         assert_(type(self.plot_data[1]) is dict, err_msg)
 
+    def test_dist_mat_to_vec_i_less_j(self):
+        """Test the index of corresponding distance vector is correct if i < j"""
+        err_msg = "dist_mat_to_vec function returning wrong values"
+        assert_equal(PSA.dist_mat_to_vec(5, 3, 4), 9, err_msg)
+
+    def test_dist_mat_to_vec_i_greater_j(self):
+        """Test the index of corresponding distance vector is correct if i > j"""
+        err_msg = "dist_mat_to_vec function returning wrong values"
+        assert_equal(PSA.dist_mat_to_vec(5, 4, 3), 9, err_msg)
 
 class TestPSAExceptions(TestCase):
     '''Tests for exceptions that should be raised
@@ -115,6 +124,23 @@ def test_get_coord_axes_bad_dims(self):
         with self.assertRaises(ValueError):
             PSA.get_coord_axes(np.zeros((5,5,5,5)))
 
+    def test_dist_mat_to_vec_func_out_of_bounds(self):
+        """Test that ValueError is raised when i or j or both are
+        out of bounds of N"""
+
+        with self.assertRaises(ValueError):
+            PSA.dist_mat_to_vec(5, 6, 4)
+            PSA.dist_mat_to_vec(5, 4, 6)
+            PSA.dist_mat_to_vec(5, 6, 6)
+
+    def test_dist_mat_to_vec_func_bad_integers(self):
+        """Test that ValueError is raised when i or j are
+        not Integers"""
+
+        with self.assertRaises(ValueError):
+            PSA.dist_mat_to_vec(5, '6', '7')
+            PSA.dist_mat_to_vec(5, float(6), 7)
+
 class _BaseHausdorffDistance(TestCase):
     '''Base Class setup and unit tests
     for various Hausdorff distance