test: Add comprehensive tests for Day 2 Part 2 Problem Dampener functionality

test/advent_code2024/solutions/day02/day2_test.exs

@@ -54,4 +54,47 @@ defmodule AdventCode2024.Solutions.Day2Test do
       assert Day2.solve("not numbers") == {:error, :invalid_format}
     end
   end
+
+  describe "solve_part2/1" do
+    test "correctly identifies safe reports with Problem Dampener from example data" do
+      input = """
+      7 6 4 2 1
+      1 2 7 8 9
+      9 7 6 2 1
+      1 3 2 4 5
+      8 6 4 4 1
+      1 3 6 7 9
+      """
+
+      assert Day2.solve_part2(input) == {:ok, 4}
+    end
+
+    test "identifies a report made safe by removing middle number" do
+      input = "1 3 2 4 5\n"
+      assert Day2.solve_part2(input) == {:ok, 1}
+    end
+
+    test "identifies a report made safe by removing duplicate number" do
+      input = "8 6 4 4 1\n"
+      assert Day2.solve_part2(input) == {:ok, 1}
+    end
+
+    test "identifies an already safe report without needing removal" do
+      input = "1 3 6 7 9\n"
+      assert Day2.solve_part2(input) == {:ok, 1}
+    end
+
+    test "identifies an unsafe report that can't be made safe" do
+      input = "1 2 7 8 9\n"
+      assert Day2.solve_part2(input) == {:ok, 0}
+    end
+
+    test "handles empty input for part 2" do
+      assert Day2.solve_part2("") == {:error, :no_valid_reports}
+    end
+
+    test "handles invalid input format for part 2" do
+      assert Day2.solve_part2("not numbers") == {:error, :invalid_format}
+    end
+  end
 end