diff --git a/answers.nix b/answers.nix
index 10c4370..f309255 100644
--- a/answers.nix
+++ b/answers.nix
@@ -2,13 +2,22 @@
   day1 = {
     part1 = "53194";
     part2 = "54249";
+    checkHaskell = true;
+    checkBash = true;
+    checkRust = true;
   };
   day2 = {
     part1 = "2406";
     part2 = "78375";
+    checkHaskell = true;
+    checkBash = true;
+    checkRust = true;
   };
   day3 = {
     part1 = "531932";
     part2 = "73646890";
+    checkHaskell = true;
+    checkBash = false;
+    checkRust = false;
   };
 }
diff --git a/flake.nix b/flake.nix
index 9b031ef..5efa668 100644
--- a/flake.nix
+++ b/flake.nix
@@ -56,31 +56,38 @@
               filter = path: type:
                 let baseName = baseNameOf (toString path);
                 in pkgs.lib.cleanSourceFilter path type &&
-                  (pkgs.lib.strings.hasInfix "rust" path ||
-                  baseName == "Cargo.toml" ||
-                  baseName == "Cargo.lock");
+                   (pkgs.lib.strings.hasInfix "rust" path ||
+                    baseName == "Cargo.toml" ||
+                    baseName == "Cargo.lock");
             };
             cargoSha256 = "sha256-e27WE9K2yby+6vzu0cDojtG0+aTdED7vt7wFgEd2dAw=";
           };
         };
         checks =
-          let mkCheck = (lang: exec: day: parts: {
-                name = "${lang}-${day}";
-                value = pkgs.testers.testEqualContents {
-                  assertion = "${lang}: ${day}";
-                  expected = pkgs.writeText "expected" ''
-                    Part 1 Answer: ${parts.part1}
-                    Part 2 Answer: ${parts.part2}
-                  '';
-                  actual = pkgs.runCommandLocal "actual" {} ''
-                    "${exec}" "${day}" < "${./input}/${day}" >$out
-                  '';
-                };
-              });
+          let mkCheck = (lang: exec: day: assertions:
+                if assertions."check${lang}" then {
+                  name = "${lang}-${day}";
+                  value = pkgs.testers.testEqualContents {
+                    assertion = "${lang}: ${day}";
+                    expected = pkgs.writeText "expected" ''
+                      Part 1 Answer: ${assertions.part1}
+                      Part 2 Answer: ${assertions.part2}
+                    '';
+                    actual = pkgs.runCommandLocal "actual" {} ''
+                      "${exec}" "${day}" < "${./input}/${day}" >$out
+                    '';
+                  };
+                }
+                else {
+                  name = "${lang}-${day}-skipped";
+                  value = pkgs.hello;
+                }
+              );
 
-          in pkgs.lib.attrsets.mapAttrs' (mkCheck "haskell" "${packages.aoc2023-haskell}/bin/aoc2023") answers
-          // pkgs.lib.attrsets.mapAttrs' (mkCheck "bash" "${packages.aoc2023-bash}/bin/aoc2023") answers
-          // pkgs.lib.attrsets.mapAttrs' (mkCheck "rust" "${packages.aoc2023-rust}/bin/aoc2023") answers;
+          in
+            pkgs.lib.attrsets.mapAttrs' (mkCheck "Haskell" "${packages.aoc2023-haskell}/bin/aoc2023") answers
+            // pkgs.lib.attrsets.mapAttrs' (mkCheck "Bash" "${packages.aoc2023-bash}/bin/aoc2023") answers
+            // pkgs.lib.attrsets.mapAttrs' (mkCheck "Rust" "${packages.aoc2023-rust}/bin/aoc2023") answers;
         defaultPackage = packages.dev-env;
       });
 }