# Testing

The default test suite is deterministic and has no elapsed-time assertions.
Configure a build, compile it, and run the tests with CTest:

```sh
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build --output-on-failure
```

The tests independently check board dimensions, square multiplicities, bounds,
overlap, and complete coverage.  They cover small unsatisfiable solver inputs, a
known order-8 solution, invalid placement diagnostics, and construction of an
order-9 solution from the order-8 fixture.  The routed best-fit order-9 solver
test checks that its search counters exactly match order 8.  The skyline tests
check smallest-width valley selection and deterministic tie-breaking, validate
an order-8 result with descending candidates, and independently validate a
direct order-9 search with ascending candidates.  An
exhaustive infeasible order also checks that all three policies visit the same
search space.  Focused D4 tests cover all eight rotations and reflections,
even and odd midlines, diagonals, corners, and the odd-board centre.  They
independently validate order-8 solutions with symmetry enabled and disabled
and check that only the enabled search records symmetry pruning.  The direct
order-9 test is deliberately separate from the
public order-9 route, which uses even-predecessor construction.  Orders 10 and
11 are not routine tests because both public routes require the same long
direct order-10 search; the route-boundary test still checks that order 11
selects odd construction.  The rendering test also formats the known order-8
solution and checks the resulting grid dimensions and coverage.

When Python is available, `reference-support` also tests the dependency-free
placement JSON validator.  If the optional OR-Tools package is present, it
additionally builds and solves the trivial order-1 CP-SAT model; otherwise that
part is skipped without changing the default test result.

## Debug and sanitizers

Use a separate build directory for each configuration:

```sh
cmake -S . -B build-debug -DCMAKE_BUILD_TYPE=Debug
cmake --build build-debug
ctest --test-dir build-debug --output-on-failure

cmake -S . -B build-asan -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DCMAKE_CXX_FLAGS="-fsanitize=address -fno-omit-frame-pointer" \
  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=address"
cmake --build build-asan
ctest --test-dir build-asan --output-on-failure

cmake -S . -B build-ubsan -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DCMAKE_CXX_FLAGS="-fsanitize=undefined -fno-omit-frame-pointer" \
  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=undefined"
cmake --build build-ubsan
ctest --test-dir build-ubsan --output-on-failure
```

The sanitizer flags shown are supported by Clang and GCC.  Other compilers may
require different flags.