diff --git a/2019/20.cpp b/2019/20.cpp
index ef2235b..fa7f882 100644
--- a/2019/20.cpp
+++ b/2019/20.cpp
@@ -1,19 +1,22 @@
 #include <algorithm>
+#include <bitset>
+#include <cctype>
 #include <cstdint>
-#include <iostream>
-#include <iomanip>
 #include <fstream>
+#include <iomanip>
+#include <iostream>
 #include <iterator>
-#include <stdexcept>
-#include <vector>
+#include <map>
+#include <queue>
+#include <queue>
 #include <set>
+#include <sstream>
+#include <stdexcept>
 #include <string>
 #include <tuple>
-#include <bitset>
-#include <queue>
-#include <cctype>
-#include <queue>
-#include <map>
+#include <vector>
+
+#include <doctest.h>
 
 #include <aocpp/Startup.hpp>
 #include <aocpp/Coord.hpp>
@@ -149,6 +152,129 @@ auto SolveMaze(Distances const& distances, bool const recursive) -> std::int64_t
 
 } // namespace
 
+TEST_SUITE("2019-20 examples") {
+  TEST_CASE("part 1 a") {
+    std::istringstream in {
+      "         A           \n"
+      "         A           \n"
+      "  #######.#########  \n"
+      "  #######.........#  \n"
+      "  #######.#######.#  \n"
+      "  #######.#######.#  \n"
+      "  #######.#######.#  \n"
+      "  #####  B    ###.#  \n"
+      "BC...##  C    ###.#  \n"
+      "  ##.##       ###.#  \n"
+      "  ##...DE  F  ###.#  \n"
+      "  #####    G  ###.#  \n"
+      "  #########.#####.#  \n"
+      "DE..#######...###.#  \n"
+      "  #.#########.###.#  \n"
+      "FG..#########.....#  \n"
+      "  ###########.#####  \n"
+      "             Z       \n"
+      "             Z       \n"
+    };
+    auto map = Grid::Parse(in);
+    auto portals = FindPortals(map);
+    auto distances = FindDistances(map, portals);
+    CHECK(SolveMaze(distances, false) == 23);
+  }
+
+  TEST_CASE("part 1") {
+    std::istringstream in {
+      "                   A               \n"
+      "                   A               \n"
+      "  #################.#############  \n"
+      "  #.#...#...................#.#.#  \n"
+      "  #.#.#.###.###.###.#########.#.#  \n"
+      "  #.#.#.......#...#.....#.#.#...#  \n"
+      "  #.#########.###.#####.#.#.###.#  \n"
+      "  #.............#.#.....#.......#  \n"
+      "  ###.###########.###.#####.#.#.#  \n"
+      "  #.....#        A   C    #.#.#.#  \n"
+      "  #######        S   P    #####.#  \n"
+      "  #.#...#                 #......VT\n"
+      "  #.#.#.#                 #.#####  \n"
+      "  #...#.#               YN....#.#  \n"
+      "  #.###.#                 #####.#  \n"
+      "DI....#.#                 #.....#  \n"
+      "  #####.#                 #.###.#  \n"
+      "ZZ......#               QG....#..AS\n"
+      "  ###.###                 #######  \n"
+      "JO..#.#.#                 #.....#  \n"
+      "  #.#.#.#                 ###.#.#  \n"
+      "  #...#..DI             BU....#..LF\n"
+      "  #####.#                 #.#####  \n"
+      "YN......#               VT..#....QG\n"
+      "  #.###.#                 #.###.#  \n"
+      "  #.#...#                 #.....#  \n"
+      "  ###.###    J L     J    #.#.###  \n"
+      "  #.....#    O F     P    #.#...#  \n"
+      "  #.###.#####.#.#####.#####.###.#  \n"
+      "  #...#.#.#...#.....#.....#.#...#  \n"
+      "  #.#####.###.###.#.#.#########.#  \n"
+      "  #...#.#.....#...#.#.#.#.....#.#  \n"
+      "  #.###.#####.###.###.#.#.#######  \n"
+      "  #.#.........#...#.............#  \n"
+      "  #########.###.###.#############  \n"
+      "           B   J   C               \n"
+      "           U   P   P               \n"
+    };
+    auto map = Grid::Parse(in);
+    auto portals = FindPortals(map);
+    auto distances = FindDistances(map, portals);
+    CHECK(SolveMaze(distances, false) == 58);
+  }
+
+  TEST_CASE("part 2") {
+    std::istringstream in {
+      "             Z L X W       C                 \n"
+      "             Z P Q B       K                 \n"
+      "  ###########.#.#.#.#######.###############  \n"
+      "  #...#.......#.#.......#.#.......#.#.#...#  \n"
+      "  ###.#.#.#.#.#.#.#.###.#.#.#######.#.#.###  \n"
+      "  #.#...#.#.#...#.#.#...#...#...#.#.......#  \n"
+      "  #.###.#######.###.###.#.###.###.#.#######  \n"
+      "  #...#.......#.#...#...#.............#...#  \n"
+      "  #.#########.#######.#.#######.#######.###  \n"
+      "  #...#.#    F       R I       Z    #.#.#.#  \n"
+      "  #.###.#    D       E C       H    #.#.#.#  \n"
+      "  #.#...#                           #...#.#  \n"
+      "  #.###.#                           #.###.#  \n"
+      "  #.#....OA                       WB..#.#..ZH\n"
+      "  #.###.#                           #.#.#.#  \n"
+      "CJ......#                           #.....#  \n"
+      "  #######                           #######  \n"
+      "  #.#....CK                         #......IC\n"
+      "  #.###.#                           #.###.#  \n"
+      "  #.....#                           #...#.#  \n"
+      "  ###.###                           #.#.#.#  \n"
+      "XF....#.#                         RF..#.#.#  \n"
+      "  #####.#                           #######  \n"
+      "  #......CJ                       NM..#...#  \n"
+      "  ###.#.#                           #.###.#  \n"
+      "RE....#.#                           #......RF\n"
+      "  ###.###        X   X       L      #.#.#.#  \n"
+      "  #.....#        F   Q       P      #.#.#.#  \n"
+      "  ###.###########.###.#######.#########.###  \n"
+      "  #.....#...#.....#.......#...#.....#.#...#  \n"
+      "  #####.#.###.#######.#######.###.###.#.#.#  \n"
+      "  #.......#.......#.#.#.#.#...#...#...#.#.#  \n"
+      "  #####.###.#####.#.#.#.#.###.###.#.###.###  \n"
+      "  #.......#.....#.#...#...............#...#  \n"
+      "  #############.#.#.###.###################  \n"
+      "               A O F   N                     \n"
+      "               A A D   M                     \n"
+    };
+    auto map = Grid::Parse(in);
+    auto portals = FindPortals(map);
+    auto distances = FindDistances(map, portals);
+    CHECK(SolveMaze(distances, true) == 396);
+  }
+}
+
+
 auto main(int argc, char** argv) -> int {
   auto map = Grid::Parse(*Startup(argc, argv));
   auto portals = FindPortals(map);