added more tests

tests/general/unit_test_a_star.cpp

@@ -8,6 +8,29 @@
 using namespace omath;
 using namespace omath::pathfinding;
 
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+static NavigationMesh make_linear_chain(int length)
+{
+    // 0 -> 1 -> 2 -> ... -> length-1  (directed)
+    NavigationMesh nav;
+    for (int i = 0; i < length; ++i)
+    {
+        const Vector3<float> v{static_cast<float>(i), 0.f, 0.f};
+        if (i + 1 < length)
+            nav.m_vertex_map[v] = {Vector3<float>{static_cast<float>(i + 1), 0.f, 0.f}};
+        else
+            nav.m_vertex_map[v] = {};
+    }
+    return nav;
+}
+
+// ---------------------------------------------------------------------------
+// Basic reachability
+// ---------------------------------------------------------------------------
+
 TEST(AStarExtra, TrivialNeighbor)
 {
     NavigationMesh nav;
@@ -78,7 +101,7 @@ TEST(AStarExtra, LongerPathAvoidsBlock)
     constexpr Vector3<float> goal = idx(2, 1);
     const auto path = Astar::find_path(start, goal, nav);
     ASSERT_FALSE(path.empty());
-    EXPECT_EQ(path.front(), goal); // Astar convention: single-element or endpoint present
+    EXPECT_EQ(path.front(), goal);
 }
 
 TEST(AstarTests, TrivialDirectNeighborPath)
@@ -91,9 +114,6 @@ TEST(AstarTests, TrivialDirectNeighborPath)
     nav.m_vertex_map.emplace(v2, std::vector<Vector3<float>>{v1});
 
     const auto path = Astar::find_path(v1, v2, nav);
-    // Current A* implementation returns the end vertex as the reconstructed
-    // path (single-element) in the simple neighbor scenario. Assert that the
-    // endpoint is present and reachable.
     ASSERT_EQ(path.size(), 1u);
     EXPECT_EQ(path.front(), v2);
 }
@@ -133,4 +153,155 @@ TEST(unit_test_a_star, finding_right_path)
     mesh.m_vertex_map[{0.f, 2.f, 0.f}] = {{0.f, 3.f, 0.f}};
     mesh.m_vertex_map[{0.f, 3.f, 0.f}] = {};
     std::ignore = omath::pathfinding::Astar::find_path({}, {0.f, 3.f, 0.f}, mesh);
-}
+}
+
+// ---------------------------------------------------------------------------
+// Directed edges
+// ---------------------------------------------------------------------------
+
+TEST(AstarTests, DirectedEdge_ForwardPathExists)
+{
+    // A -> B only; path from A to B should succeed
+    NavigationMesh nav;
+    constexpr Vector3<float> a{0.f, 0.f, 0.f};
+    constexpr Vector3<float> b{1.f, 0.f, 0.f};
+    nav.m_vertex_map[a] = {b};
+    nav.m_vertex_map[b] = {}; // no edge back
+
+    const auto path = Astar::find_path(a, b, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), b);
+}
+
+TEST(AstarTests, DirectedEdge_ReversePathMissing)
+{
+    // A -> B only; path from B to A should fail
+    NavigationMesh nav;
+    constexpr Vector3<float> a{0.f, 0.f, 0.f};
+    constexpr Vector3<float> b{1.f, 0.f, 0.f};
+    nav.m_vertex_map[a] = {b};
+    nav.m_vertex_map[b] = {};
+
+    const auto path = Astar::find_path(b, a, nav);
+    EXPECT_TRUE(path.empty());
+}
+
+// ---------------------------------------------------------------------------
+// Vertex snapping
+// ---------------------------------------------------------------------------
+
+TEST(AstarTests, OffMeshStart_SnapsToNearestVertex)
+{
+    NavigationMesh nav;
+    constexpr Vector3<float> v1{0.f, 0.f, 0.f};
+    constexpr Vector3<float> v2{10.f, 0.f, 0.f};
+    nav.m_vertex_map[v1] = {v2};
+    nav.m_vertex_map[v2] = {v1};
+
+    // Start is slightly off v1 but closer to it than to v2
+    constexpr Vector3<float> off_start{0.1f, 0.f, 0.f};
+    const auto path = Astar::find_path(off_start, v2, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), v2);
+}
+
+TEST(AstarTests, OffMeshEnd_SnapsToNearestVertex)
+{
+    NavigationMesh nav;
+    constexpr Vector3<float> v1{0.f, 0.f, 0.f};
+    constexpr Vector3<float> v2{10.f, 0.f, 0.f};
+    nav.m_vertex_map[v1] = {v2};
+    nav.m_vertex_map[v2] = {v1};
+
+    // Goal is slightly off v2 but closer to it than to v1
+    constexpr Vector3<float> off_goal{9.9f, 0.f, 0.f};
+    const auto path = Astar::find_path(v1, off_goal, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), v2);
+}
+
+// ---------------------------------------------------------------------------
+// Cycle handling
+// ---------------------------------------------------------------------------
+
+TEST(AstarTests, CyclicGraph_FindsPathWithoutLooping)
+{
+    // Triangle: A <-> B <-> C <-> A
+    NavigationMesh nav;
+    constexpr Vector3<float> a{0.f, 0.f, 0.f};
+    constexpr Vector3<float> b{1.f, 0.f, 0.f};
+    constexpr Vector3<float> c{0.5f, 1.f, 0.f};
+    nav.m_vertex_map[a] = {b, c};
+    nav.m_vertex_map[b] = {a, c};
+    nav.m_vertex_map[c] = {a, b};
+
+    const auto path = Astar::find_path(a, c, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), c);
+}
+
+TEST(AstarTests, SelfLoopVertex_DoesNotBreakSearch)
+{
+    // Vertex with itself as a neighbor
+    NavigationMesh nav;
+    constexpr Vector3<float> a{0.f, 0.f, 0.f};
+    constexpr Vector3<float> b{1.f, 0.f, 0.f};
+    nav.m_vertex_map[a] = {a, b}; // self-loop on a
+    nav.m_vertex_map[b] = {a};
+
+    const auto path = Astar::find_path(a, b, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), b);
+}
+
+// ---------------------------------------------------------------------------
+// Longer chains
+// ---------------------------------------------------------------------------
+
+TEST(AstarTests, LinearChain_ReachesEnd)
+{
+    constexpr int kLength = 10;
+    const NavigationMesh nav = make_linear_chain(kLength);
+
+    const Vector3<float> start{0.f, 0.f, 0.f};
+    const Vector3<float> goal{static_cast<float>(kLength - 1), 0.f, 0.f};
+
+    const auto path = Astar::find_path(start, goal, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), goal);
+}
+
+TEST(AstarTests, LinearChain_MidpointReachable)
+{
+    constexpr int kLength = 6;
+    const NavigationMesh nav = make_linear_chain(kLength);
+
+    const Vector3<float> start{0.f, 0.f, 0.f};
+    const Vector3<float> mid{3.f, 0.f, 0.f};
+
+    const auto path = Astar::find_path(start, mid, nav);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), mid);
+}
+
+// ---------------------------------------------------------------------------
+// Serialize -> pathfind integration
+// ---------------------------------------------------------------------------
+
+TEST(AstarTests, PathfindAfterSerializeDeserialize)
+{
+    NavigationMesh nav;
+    constexpr Vector3<float> a{0.f, 0.f, 0.f};
+    constexpr Vector3<float> b{1.f, 0.f, 0.f};
+    constexpr Vector3<float> c{2.f, 0.f, 0.f};
+    nav.m_vertex_map[a] = {b};
+    nav.m_vertex_map[b] = {a, c};
+    nav.m_vertex_map[c] = {b};
+
+    NavigationMesh nav2;
+    nav2.deserialize(nav.serialize());
+
+    const auto path = Astar::find_path(a, c, nav2);
+    ASSERT_FALSE(path.empty());
+    EXPECT_EQ(path.back(), c);
+}