Add pure game model + GTest board tests and scaffolding

Add SDL-free Board model: Board.h, Board.cpp
Add unit tests for Board using Google Test: test_board.cpp
Integrate test_board into CMake and register with CTest: update CMakeLists.txt
Add gtest to vcpkg.json so CMake can find GTest
Add high-level refactor plan: plan-spacetrisRefactor.prompt.md
Update internal TODOs to mark logic extraction complete
This scaffolds deterministic, testable game logic and CI-friendly tests without changing existing runtime behavior.

CMakeLists.txt

@@ -201,6 +201,20 @@ if(EXISTS "${CMAKE_SOURCE_DIR}/vcpkg_installed/x64-windows/include")
     target_include_directories(spacetris_tests PRIVATE "${CMAKE_SOURCE_DIR}/vcpkg_installed/x64-windows/include")
 endif()
 
+# GoogleTest-based board unit tests
+find_package(GTest CONFIG REQUIRED)
+add_executable(test_board
+    tests/test_board.cpp
+    src/logic/Board.cpp
+)
+target_include_directories(test_board PRIVATE ${CMAKE_SOURCE_DIR}/src)
+target_link_libraries(test_board PRIVATE GTest::gtest_main)
+add_test(NAME BoardTests COMMAND test_board)
+
+if(EXISTS "${CMAKE_SOURCE_DIR}/vcpkg_installed/x64-windows/include")
+    target_include_directories(test_board PRIVATE "${CMAKE_SOURCE_DIR}/vcpkg_installed/x64-windows/include")
+endif()
+
 # Add new src subfolders to include path so old #includes continue to work
 target_include_directories(spacetris PRIVATE
     ${CMAKE_SOURCE_DIR}/src

tests/test_board.cpp

@@ -1,31 +1,38 @@
 #include "../src/logic/Board.h"
-#include <cassert>
+#include <gtest/gtest.h>
-#include <iostream>
 
-int main()
+using logic::Board;
+
+TEST(BoardTests, InitiallyEmpty)
 {
-    using logic::Board;
     Board b;
-    // board starts empty
     for (int y = 0; y < Board::Height; ++y)
         for (int x = 0; x < Board::Width; ++x)
-            assert(b.at(x,y) == Board::Cell::Empty);
+            EXPECT_EQ(b.at(x, y), Board::Cell::Empty);
+}
 
-    // fill a single full row at bottom
+TEST(BoardTests, ClearSingleFullLine)
+{
+    Board b;
     int y = Board::Height - 1;
     for (int x = 0; x < Board::Width; ++x) b.set(x, y, Board::Cell::Filled);
     int cleared = b.clearFullLines();
-    assert(cleared == 1);
+    EXPECT_EQ(cleared, 1);
-    // bottom row should be empty after clear
+    for (int x = 0; x < Board::Width; ++x) EXPECT_EQ(b.at(x, Board::Height - 1), Board::Cell::Empty);
-    for (int x = 0; x < Board::Width; ++x) assert(b.at(x, Board::Height - 1) == Board::Cell::Empty);
+}
 
-    // fill two non-adjacent rows and verify both clear
+TEST(BoardTests, ClearTwoNonAdjacentLines)
+{
+    Board b;
     int y1 = Board::Height - 1;
     int y2 = Board::Height - 3;
     for (int x = 0; x < Board::Width; ++x) { b.set(x, y1, Board::Cell::Filled); b.set(x, y2, Board::Cell::Filled); }
-    cleared = b.clearFullLines();
+    int cleared = b.clearFullLines();
-    assert(cleared == 2);
+    EXPECT_EQ(cleared, 2);
-
+}
-    std::cout << "tests/test_board: all assertions passed\n";
+
-    return 0;
+int main(int argc, char** argv)
+{
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
 }

vcpkg.json

@@ -8,6 +8,7 @@
 		},
 		"enet",
 		"catch2",
+		"gtest",
 		"cpr",
 		"nlohmann-json",
 		"ffmpeg"