+
+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));
+}
+
+TEST(Step, TwoSuccessors) {
+ auto s = std::make_shared<Step>(Step{{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}}, nullptr});
+ std::vector<Step*> suc = s->successors(s);
+ EXPECT_THAT(suc, testing::UnorderedElementsAre(
+ Field(&Step::board, Field(&Board::board, ElementsAreArray({1,2,3,4,5,6,7,8,9,10,11,12,13,14,0,15}))),
+ Field(&Step::board, Field(&Board::board, ElementsAreArray({1,2,3,4,5,6,7,8,9,10,11,0,13,14,15,12})))));
+}
+
+TEST(Step, FourSuccessors) {
+ auto s = std::make_shared<Step>(Step{{{1,2,3,4,5,0,6,7,8,9,10,11,12,13,14,15}}, nullptr});
+ std::vector<Step*> suc = s->successors(s);
+ EXPECT_THAT(suc, testing::UnorderedElementsAre(
+ Field(&Step::board, Field(&Board::board, ElementsAreArray({1,2,3,4,0,5,6,7,8,9,10,11,12,13,14,15}))),
+ Field(&Step::board, Field(&Board::board, ElementsAreArray({1,2,3,4,5,6,0,7,8,9,10,11,12,13,14,15}))),
+ Field(&Step::board, Field(&Board::board, ElementsAreArray({1,0,3,4,5,2,6,7,8,9,10,11,12,13,14,15}))),
+ Field(&Step::board, Field(&Board::board, ElementsAreArray({1,2,3,4,5,9,6,7,8,0,10,11,12,13,14,15})))));
+}
+
+TEST(Step, Output) {
+ auto s1 = std::make_shared<Step>(Step{{{1,2,3,4,5,7,11,8,9,6,0,12,13,10,14,15}}, nullptr});
+ auto s2 = std::make_shared<Step>(Step{{{1,2,3,4,5,7,0,8,9,6,11,12,13,10,14,15}}, s1});
+ auto s3 = std::make_shared<Step>(Step{{{1,2,3,4,5,0,7,8,9,6,11,12,13,10,14,15}}, s2});
+ auto s4 = std::make_shared<Step>(Step{{{1,2,3,4,5,6,7,8,9,0,11,12,13,10,14,15}}, s3});
+ auto s5 = std::make_shared<Step>(Step{{{1,2,3,4,5,6,7,8,9,10,11,12,13,0,14,15}}, s4});
+ auto s6 = std::make_shared<Step>(Step{{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,0,15}}, s5});
+ auto s7 = std::make_shared<Step>(Step{{{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0}}, s6});
+ std::ostringstream actual;
+ actual << *s7;
+ std::ostringstream expected;
+ expected << "11 down" << std::endl
+ << "7 right" << std::endl
+ << "6 up" << std::endl
+ << "10 up" << std::endl
+ << "14 left" << std::endl
+ << "15 left" << std::endl;
+ EXPECT_EQ(expected.str(), actual.str());
+}