A = [1,0;0,1];
unit_test_equals("The identity is positive definite", ...
		 true, ...
		 is_positive_definite(A));

A = [1,1;1,1];
unit_test_equals("All-ones matrix is not positive definite", ...
		 false, ...
		 is_positive_definite(A));

A = [5,1,2;1,6,3;2,3,7];
unit_test_equals("A diagonally-dominant matrix is positive definite", ...
		 true, ...
		 is_positive_definite(A));
