A distance metric

[slidingtile] / sliding_tile_lib_test.cc

diff --git a/sliding_tile_lib_test.cc b/sliding_tile_lib_test.cc
index 12cc46b8a051394b03d7fd93b7d724a25917c92c..f1427950c4bbb982d5d2b9ceb1bae8968dee8e2e 100644 (file)
--- a/sliding_tile_lib_test.cc
+++ b/sliding_tile_lib_test.cc
@@ -86,3 +86,32 @@ TEST(Board, NoHole) {
   Board b{{16,14,9,13,3,1,12,8,16,11,6,4,7,5,2,10}};
   EXPECT_THROW(b.hole(), std::runtime_error);
 }
+
+TEST(Board, ZeroDistance) {
+  Board b{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
+  EXPECT_EQ(0, b.distance(b));
+}
+
+TEST(Board, DistanceAdjacentTilesFlipped) {
+  Board b1{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
+  Board b2{{2,1,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
+  EXPECT_EQ(2, b1.distance(b2));
+}
+
+TEST(Board, DistanceOneMoveRemaining) {
+  Board b1{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
+  Board b2{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,0,15}};
+  EXPECT_EQ(2, b1.distance(b2));
+}
+
+TEST(Board, DistanceCornersSwapped) {
+  Board b1{{0,2,3,13,5,6,7,8,9,10,11,12,4,14,15,1}};
+  Board b2{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
+  EXPECT_EQ(24, b1.distance(b2));
+}
+
+TEST(Board, MaxDistance) {
+  Board b1{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}};
+  Board b2{{0,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1}};
+  EXPECT_EQ(64, b1.distance(b2));
+}