added test_costFunctionReg & included it in the test suite

ex2/test_costFunctionReg.m

@@ -0,0 +1,32 @@
+function test_costFunctionReg ()
+    tolerance = 1e-3;
+    % Test 1, w/ lambda = 3  
+    % From TA Colin Beckingham, at https://class.coursera.org/ml-005/forum/thread?thread_id=943#post-4593    
+    theta =  [2; 1; -9];
+    X = magic(3);
+    y = [1; -0.2; 3];
+    lambda = 3;
+
+    J_exp =  50.971;
+    grad_exp = [-6.1081 -7.1932 -12.3540];
+
+    [J, grad] = costFunctionReg(theta, X, y, lambda);
+
+    assert(J, J_exp, tolerance );
+    assert(grad, grad_exp, tolerance);    
+
+    % Test 2, w/ lambda = 0.1
+    % From TA Colin Beckingham, at https://class.coursera.org/ml-005/forum/thread?thread_id=943#post-4666
+    theta =  [2; 1; -9];
+    X = magic(3);
+    y = [1; -0.2; 3];    
+    lambda = 0.1;
+    J_exp_2 =  11.338;
+    grad_exp_2 = [-6.1081 -8.1598 -3.6540];
+
+    [J, grad] = costFunctionReg(theta, X, y, lambda);
+
+    assert(J, J_exp_2, tolerance );
+    assert(grad, grad_exp_2, tolerance);
+
+endfunction

ex2/test_ex2.m

@@ -6,4 +6,6 @@
 
 %!test test_costfunction_nontrivial()
 
-%!test test_predict()
+%!test test_predict()
+
+%!test test_costFunctionReg()