[four-in-a-row] Remove TODOs.

[Arnaud B. <arnaudb src gnome org>]

commit ab789ce4cd55aaa5f07e0138a26510c991587903
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Tue Dec 24 15:04:22 2019 +0100

    Remove TODOs.

 src/ai.vala      | 3 ++-
 src/test-ai.vala | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/src/ai.vala b/src/ai.vala
index 8979f1d..d02e77c 100644
--- a/src/ai.vala
+++ b/src/ai.vala
@@ -406,11 +406,12 @@ private class DecisionTree
             level = Difficulty.MEDIUM;
             plies = 7;
         }
-        else // TODO if (vstr [0] == 'c') / else assert_not_reached ();
+        else if (vstr [0] == 'c')
         {
             level = Difficulty.HARD;
             plies = 7;
         }
+        else assert_not_reached ();
     }
 
     /* utility function for testing purposes */
diff --git a/src/test-ai.vala b/src/test-ai.vala
index 953f688..b87a65e 100644
--- a/src/test-ai.vala
+++ b/src/test-ai.vala
@@ -79,7 +79,7 @@ private static inline void test_forward_diagonal_win ()
 /* Tests if the AI makes moves so as to take up immediate backward diagonal wins.*/
 private static inline void test_backward_diagonal_win ()
 {
-    assert_true (playgame ("5422327343142110") == 0);    // TODO no "a"?
+    assert_true (playgame ("a5422327343142110") == 0);
     assert_true (playgame ("a1415113315143220") == 1);
     assert_true (playgame ("a547323452213345110") == 0);
     assert_true (playgame ("a4256424426621271412117175776343330") == 2);