Minimal test for expected values

test/test_loss.f90

@@ -7,6 +7,42 @@ program test_loss
 
   logical :: ok = .true.
 
+  block
+
+    type(mse) :: loss
+    real :: true(2) = [1., 2.]
+    real :: pred(2) = [3., 4.]
+
+    if (.not. loss % eval(true, pred) == 4) then
+      write(stderr, '(a)') 'expected output of mse % eval().. failed'
+      ok = .false.
+    end if
+
+    if (.not. all(loss % derivative(true, pred) == [2, 2])) then
+      write(stderr, '(a)') 'expected output of mse % derivative().. failed'
+      ok = .false.
+    end if
+
+  end block
+
+  block
+
+    type(quadratic) :: loss
+    real :: true(4) = [1., 2., 3., 4.]
+    real :: pred(4) = [3., 4., 5., 6.]
+
+    if (.not. loss % eval(true, pred) == 8) then
+      write(stderr, '(a)') 'expected output of quadratic % eval().. failed'
+      ok = .false.
+    end if
+
+    if (.not. all(loss % derivative(true, pred) == [2, 2, 2, 2])) then
+      write(stderr, '(a)') 'expected output of quadratic % derivative().. failed'
+      ok = .false.
+    end if
+
+  end block
+
   if (ok) then
     print '(a)', 'test_loss: All tests passed.'
   else