MDBoxIteratorTest.h

// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#pragma once

#include "MantidDataObjects/MDBox.h"
#include "MantidDataObjects/MDBoxIterator.h"
#include "MantidDataObjects/MDEventFactory.h"
#include "MantidDataObjects/MDGridBox.h"
#include "MantidGeometry/MDGeometry/MDBoxImplicitFunction.h"
#include "MantidGeometry/MDGeometry/MDImplicitFunction.h"
#include "MantidGeometry/MDGeometry/MDPlane.h"
#include "MantidKernel/System.h"
#include "MantidKernel/Timer.h"
#include "MantidKernel/WarningSuppressions.h"
#include "MantidTestHelpers/MDEventsTestHelper.h"
#include <cxxtest/TestSuite.h>
#include <gmock/gmock.h>

using namespace Mantid::DataObjects;
using namespace Mantid::API;
using namespace Mantid;
using namespace Mantid::Kernel;
using Mantid::Geometry::MDBoxImplicitFunction;
using Mantid::Geometry::MDImplicitFunction;
using Mantid::Geometry::MDPlane;

class MDBoxIteratorTest : public CxxTest::TestSuite {
public:
  using gbox_t = MDGridBox<MDLeanEvent<1>, 1>;
  using ibox_t = MDBoxBase<MDLeanEvent<1>, 1>;

  //--------------------------------------------------------------------------------------
  /** Make a gridded box with this structure:
              Names                                   Width of each box

               A                                        64
               |
      B0 -- B1 -------- B2 ------------ B3              16
      |                 |
    C00-3        C20 C21 C22 C23                         4
                      |
                  D210 D211 D212 D213                    1

   */
  gbox_t *A;
  ibox_t *B1, *B3;
  gbox_t *B0, *B2;
  ibox_t *C00, *C01, *C02, *C03;
  ibox_t *C20, *C22, *C23;
  gbox_t *C21;
  ibox_t *D210, *D211, *D212, *D213;
  void setUp() override {
    // Top level grid box
    A = MDEventsTestHelper::makeMDGridBox<1>(4, 1, 0.0, 64.0);
    A->splitContents(0); // Split B0 into C00 to C03
    A->splitContents(2); // Split B2 into C20 to C23
    B0 = dynamic_cast<gbox_t *>(A->getChild(0));
    B2 = dynamic_cast<gbox_t *>(A->getChild(2));
    B2->splitContents(1); // Split C21 into D210 to D212

    B1 = dynamic_cast<ibox_t *>(A->getChild(1));
    B3 = dynamic_cast<ibox_t *>(A->getChild(3));
    TS_ASSERT_EQUALS(B1, dynamic_cast<ibox_t *>(A->getChild(1)));
    C00 = dynamic_cast<ibox_t *>(B0->getChild(0));
    C01 = dynamic_cast<ibox_t *>(B0->getChild(1));
    C02 = dynamic_cast<ibox_t *>(B0->getChild(2));
    C03 = dynamic_cast<ibox_t *>(B0->getChild(3));
    C20 = dynamic_cast<ibox_t *>(B2->getChild(0));
    C21 = dynamic_cast<gbox_t *>(B2->getChild(1));
    C22 = dynamic_cast<ibox_t *>(B2->getChild(2));
    C23 = dynamic_cast<ibox_t *>(B2->getChild(3));
    D210 = dynamic_cast<ibox_t *>(C21->getChild(0));
    D211 = dynamic_cast<ibox_t *>(C21->getChild(1));
    D212 = dynamic_cast<ibox_t *>(C21->getChild(2));
    D213 = dynamic_cast<ibox_t *>(C21->getChild(3));
  }

  void tearDown() override {
    delete A->getBoxController();
    delete A;
  }

  //--------------------------------------------------------------------------------------
  void test_ctor_with_null_box_fails() {
    using boxit_t = MDBoxIterator<MDLeanEvent<1>, 1>;
    TS_ASSERT_THROWS_ANYTHING(new boxit_t(nullptr, 10, false););
  }

  //--------------------------------------------------------------------------------------
  /** Increment the iterator and return true if the next box is the expected
   * one*/
  bool nextIs(MDBoxIterator<MDLeanEvent<1>, 1> *it, ibox_t *expected) {
    // std::cout << it->getBox()->getExtentsStr() << '\n';
    if (!it->next())
      return false;
    if (it->getBox() != expected)
      return false;
    return true;
  }

  void test_iterator_basic() {
    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false);

    // Start with the top one
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(nextIs(it.get(), B0));
    TS_ASSERT(nextIs(it.get(), C00));
    TS_ASSERT(nextIs(it.get(), C01));
    TS_ASSERT(nextIs(it.get(), C02));
    TS_ASSERT(nextIs(it.get(), C03));
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), B2));
    TS_ASSERT(nextIs(it.get(), C20));
    TS_ASSERT(nextIs(it.get(), C21));
    TS_ASSERT(nextIs(it.get(), D210));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    TS_ASSERT(nextIs(it.get(), D213));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(nextIs(it.get(), B3));
    // No more!
    TS_ASSERT(!it->next());
    // Calling next again does not cause problems.
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_depth_limit_1() {
    // Limit depth to 1 (the B level)
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 1, false);
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(nextIs(it.get(), B0));
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), B2));
    TS_ASSERT(nextIs(it.get(), B3));
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_depth_limit_0() {
    // Limit depth to 0 (the A level)
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 0, false);
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_starting_deeper() {
    // Start at a depth of 1 (on B0)
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(B0, 20, false);
    TS_ASSERT_EQUALS(it->getBox(), B0);
    TS_ASSERT(nextIs(it.get(), C00));
    TS_ASSERT(nextIs(it.get(), C01));
    TS_ASSERT(nextIs(it.get(), C02));
    TS_ASSERT(nextIs(it.get(), C03));
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_leaf_only() {
    // Leaf-only iterator = skips anything with children
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true);

    // This is the first leaf node
    TS_ASSERT_EQUALS(it->getBox(), C00);
    TS_ASSERT(nextIs(it.get(), C01));
    TS_ASSERT(nextIs(it.get(), C02));
    TS_ASSERT(nextIs(it.get(), C03));
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), C20));
    TS_ASSERT(nextIs(it.get(), D210));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    TS_ASSERT(nextIs(it.get(), D213));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(nextIs(it.get(), B3));
    // No more!
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_leaf_only_depth_2() {
    // A node is considered a 'leaf' if it is at maxDepth
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 2, true);

    // This is the first leaf node
    TS_ASSERT_EQUALS(it->getBox(), C00);
    TS_ASSERT(nextIs(it.get(), C01));
    TS_ASSERT(nextIs(it.get(), C02));
    TS_ASSERT(nextIs(it.get(), C03));
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), C20));
    TS_ASSERT(
        nextIs(it.get(), C21)); // This is now a 'leaf' due to the maxDepth
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(nextIs(it.get(), B3));
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_leaf_only_depth_1() {
    // A node is considered a 'leaf' if it is at maxDepth
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 1, true);
    // This is the first leaf node
    TS_ASSERT_EQUALS(it->getBox(), B0);
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), B2));
    TS_ASSERT(nextIs(it.get(), B3));
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_leaf_only_depth_0() {
    // A node is considered a 'leaf' if it is at maxDepth
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 0, true);
    // This is the ONLY leaf node
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_leaf_only_starting_deeper() {
    // Now we start at B2 and look at only leaves
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(B2, 10, true);
    TS_ASSERT_EQUALS(it->getBox(), C20);
    TS_ASSERT(nextIs(it.get(), D210));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    TS_ASSERT(nextIs(it.get(), D213));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_leaf_only_starting_deeper_depth_limited() {
    // Now we start at B2 and look at only leaves up to depth 2
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(B2, 2, true);
    TS_ASSERT_EQUALS(it->getBox(), C20);
    TS_ASSERT(nextIs(it.get(), C21));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  /** If you have just a MD Box, there is only one return from the iterator,
   * and it doesn't crash or anything ;)
   */
  void test_iterator_just_one_box() {
    // Top level grid box
    ibox_t *A = MDEventsTestHelper::makeMDBox1();
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false);
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());

    BoxController *const bc = A->getBoxController();
    delete bc;
    delete A;
  }

  //--------------------------------------------------------------------------------------
  /** Get the inner data from an MDBox
   */
  void test_iterator_getInnerData() {
    // Make a MDBox with 10 events
    ibox_t *A = MDEventsTestHelper::makeMDBox1();
    MDEventsTestHelper::feedMDBox<1>(A, 1, 10, 0.5, 1.0);
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false);
    TS_ASSERT_EQUALS(it->getBox(), A);
    // It has some events!
    TS_ASSERT_EQUALS(it->getNumEvents(), 10);
    // Check inner data
    for (size_t i = 0; i < 10; i++) {
      TS_ASSERT_DELTA(it->getInnerSignal(i), 1.0, 1e-6);
      TS_ASSERT_DELTA(it->getInnerError(i), 1.0, 1e-6);
      TS_ASSERT_DELTA(it->getInnerRunIndex(i), 0, 0);
      TS_ASSERT_DELTA(it->getInnerDetectorID(i), 0, 0);
      TS_ASSERT_DELTA(it->getInnerPosition(i, 0), 0.5 + double(i), 1e-6);
    }
    // Other functions that go back to the box
    TS_ASSERT_DELTA(it->getCenter()[0], 5.0, 1e-5);

    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());

    BoxController *const bc = A->getBoxController();
    delete bc;
    delete A;
  }
  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_above11() {
    // Implicit function = only boxes with x > 5.0
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {11.0};
    func->addPlane(MDPlane(1, normal, origin));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false,
                                                                 func.get());

    // Start with the top one
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(nextIs(it.get(), B0));
    // C00-C01 are outside the range
    TS_ASSERT(nextIs(it.get(), C02));
    TS_ASSERT(nextIs(it.get(), C03));
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), B2));
    TS_ASSERT(nextIs(it.get(), C20));
    TS_ASSERT(nextIs(it.get(), C21));
    TS_ASSERT(nextIs(it.get(), D210));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    TS_ASSERT(nextIs(it.get(), D213));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(nextIs(it.get(), B3));
    // No more!
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_above11_leafOnly() {
    // Implicit function = only boxes with x > 5.0
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {11.0};
    func->addPlane(MDPlane(1, normal, origin));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true,
                                                                 func.get());

    // C00-C01 are outside the range, so the first one is C02
    TS_ASSERT_EQUALS(it->getBox(), C02);
    TS_ASSERT(nextIs(it.get(), C03));
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), C20));
    TS_ASSERT(nextIs(it.get(), D210));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    TS_ASSERT(nextIs(it.get(), D213));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(nextIs(it.get(), B3));
    // No more!
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_above17() {
    // Implicit function = only boxes with x > 17.0
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {17.0};
    func->addPlane(MDPlane(1, normal, origin));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false,
                                                                 func.get());

    // Start with the top one
    TS_ASSERT_EQUALS(it->getBox(), A);
    // B0 (and all children) are outside the range
    TS_ASSERT(nextIs(it.get(), B1));
    TS_ASSERT(nextIs(it.get(), B2));
    TS_ASSERT(nextIs(it.get(), C20));
    TS_ASSERT(nextIs(it.get(), C21));
    TS_ASSERT(nextIs(it.get(), D210));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    TS_ASSERT(nextIs(it.get(), D213));
    TS_ASSERT(nextIs(it.get(), C22));
    TS_ASSERT(nextIs(it.get(), C23));
    TS_ASSERT(nextIs(it.get(), B3));
    // No more!
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_between_37_and_39() {
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {37.1f};
    func->addPlane(MDPlane(1, normal, origin));
    coord_t normal2[1] = {-1.0};
    coord_t origin2[1] = {38.9f};
    func->addPlane(MDPlane(1, normal2, origin2));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false,
                                                                 func.get());

    // Go down to the only two leaf boxes that are in range
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(nextIs(it.get(), B2));
    TS_ASSERT(nextIs(it.get(), C21));
    TS_ASSERT(nextIs(it.get(), D211));
    TS_ASSERT(nextIs(it.get(), D212));
    // No more!
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_between_37_and_39_leafOnly() {
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {37.1f};
    func->addPlane(MDPlane(1, normal, origin));
    coord_t normal2[1] = {-1.0};
    coord_t origin2[1] = {38.9f};
    func->addPlane(MDPlane(1, normal2, origin2));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true,
                                                                 func.get());

    // Only two leaf boxes are in range
    TS_ASSERT_EQUALS(it->getBox(), D211);
    TS_ASSERT(nextIs(it.get(), D212));
    // No more!
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_noBoxInRange() {
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {234};
    func->addPlane(MDPlane(1, normal, origin));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, false,
                                                                 func.get());

    // Returns the first box but that's it
    TS_ASSERT_EQUALS(it->getBox(), A);
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  //--------------------------------------------------------------------------------------
  void test_iterator_withImplicitFunction_noBoxInRange_leafOnly() {
    auto func = std::make_unique<MDImplicitFunction>();
    coord_t normal[1] = {+1.0};
    coord_t origin[1] = {234};
    func->addPlane(MDPlane(1, normal, origin));

    // Create an iterator
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true,
                                                                 func.get());

    // Nothing in the iterator!
    TS_ASSERT_EQUALS(it->getDataSize(), 0);
    TS_ASSERT(!it->next());
    TS_ASSERT(!it->next());
  }

  void test_getIsMasked() {
    // Mock MDBox. Only one method of interest to the mocking.
    class MockMDBox : public MDBox<MDLeanEvent<2>, 2> {
      API::BoxController *const pBC;

    public:
      MockMDBox()
          : MDBox<MDLeanEvent<2>, 2>(new API::BoxController(2)),
            pBC(MDBox<MDLeanEvent<2>, 2>::getBoxController())

      {}
      GNU_DIAG_OFF_SUGGEST_OVERRIDE
      MOCK_CONST_METHOD0(getIsMasked, bool());
      GNU_DIAG_ON_SUGGEST_OVERRIDE
      ~MockMDBox() override { delete pBC; }
    };

    MockMDBox mockBox;

    MDBoxIterator<MDLeanEvent<2>, 2> it(&mockBox, 1, true);

    // All that we want to test is that iterator::getIsMasked calls
    // MDBoxBase::getIsMasked
    EXPECT_CALL(mockBox, getIsMasked()).Times(1);
    it.getIsMasked();

    TSM_ASSERT("Iterator does not use boxes as expected",
               testing::Mock::VerifyAndClearExpectations(&mockBox));
  }

  void test_skip_masked_detectors() {
    auto setupIterator =
        std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true);

    // mask box 0, unmask 1 and Mask box 2. From box 3 onwards, boxes will be
    // unmasked.
    setupIterator->getBox()->mask();
    setupIterator->next(1);
    setupIterator->getBox()->unmask();
    setupIterator->next(1);
    setupIterator->getBox()->mask();
    setupIterator->next(1);

    auto evaluationIterator =
        std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true);
    TS_ASSERT_THROWS_NOTHING(evaluationIterator->next());
    TSM_ASSERT_EQUALS("Should have skipped to the first non-masked box", 1,
                      evaluationIterator->getPosition());
    TS_ASSERT_THROWS_NOTHING(evaluationIterator->next());
    TSM_ASSERT_EQUALS("Should have skipped to the second non-masked box", 3,
                      evaluationIterator->getPosition());
    TSM_ASSERT("The last box should be masked",
               !evaluationIterator->getIsMasked());
  }

  void test_no_skipping_policy() {
    auto setupIterator =
        std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true);

    // mask box 0, unmask 1 and Mask box 2. From box 3 onwards, boxes will be
    // unmasked.
    setupIterator->getBox()->mask();
    setupIterator->next(1);
    setupIterator->getBox()->unmask();
    setupIterator->next(1);
    setupIterator->getBox()->mask();
    setupIterator->next(1);

    auto evaluationIterator =
        std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(
            A, 20, true, new SkipNothing); // Using skip nothing policy.
    TS_ASSERT_THROWS_NOTHING(evaluationIterator->next());
    TSM_ASSERT_EQUALS("Should NOT have skipped to the first box", 1,
                      evaluationIterator->getPosition());
    TS_ASSERT_THROWS_NOTHING(evaluationIterator->next());
    TSM_ASSERT_EQUALS("Should NOT have skipped to the second box", 2,
                      evaluationIterator->getPosition());
    TS_ASSERT_THROWS_NOTHING(evaluationIterator->next());
    TSM_ASSERT_EQUALS("Should NOT have skipped to the third box", 3,
                      evaluationIterator->getPosition());
  }

  void test_custom_skipping_policy() {
    /// Mock Skipping Policy Type to inject.
    class MockSkippingPolicy : public SkippingPolicy {
    public:
      GNU_DIAG_OFF_SUGGEST_OVERRIDE
      MOCK_CONST_METHOD0(keepGoing, bool());
      MOCK_METHOD0(Die, void());
      GNU_DIAG_ON_SUGGEST_OVERRIDE
      ~MockSkippingPolicy() override { Die(); }
    };

    MockSkippingPolicy *mockPolicy = new MockSkippingPolicy;
    auto evaluationIterator =
        std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(
            A, 20, true,
            mockPolicy); // Using custom policy

    EXPECT_CALL(*mockPolicy, Die())
        .Times(1); // Should call destructor automatically within MDBoxIterator
    EXPECT_CALL(*mockPolicy, keepGoing())
        .Times(static_cast<int>(
            evaluationIterator->getDataSize())); // Should apply test

    while (evaluationIterator->next()) // Keep calling next while true. Will
                                       // iterate through all boxes.
    {
    }

    // verifying that mockPoly is deleted requires calling evaluationIterator's
    // destructor before the end of the function.
    evaluationIterator.reset();

    TSM_ASSERT("Has not used SkippingPolicy as expected.",
               testing::Mock::VerifyAndClearExpectations(mockPolicy));
  }

  void test_getNormalizedSignal_with_mask() {
    // Make a MDBox with 10 events
    ibox_t *A = MDEventsTestHelper::makeMDBox1();
    MDEventsTestHelper::feedMDBox<1>(A, 1, 10, 0.5, 1.0);
    auto it = std::make_unique<MDBoxIterator<MDLeanEvent<1>, 1>>(A, 20, true);

    // Initially the box is unmasked
    TS_ASSERT_DELTA(it->getNormalizedSignal(), 1.0, 1e-5);

    it->next();

    // Now mask the box
    it->getBox()->mask();
    // For masked boxes, getNormalizedSignal() should return NaN.
    TS_ASSERT(std::isnan(it->getNormalizedSignal()));

    delete A->getBoxController();
    delete A;
  }
};

class MDBoxIteratorTestPerformance : public CxxTest::TestSuite {
  MDGridBox<MDLeanEvent<3>, 3> *top;

public:
  // This pair of boilerplate methods prevent the suite being created statically
  // This means the constructor isn't called when running other tests
  static MDBoxIteratorTestPerformance *createSuite() {
    return new MDBoxIteratorTestPerformance();
  }
  static void destroySuite(MDBoxIteratorTestPerformance *suite) {
    delete suite;
  }

  MDBoxIteratorTestPerformance() {
    // 1968876 boxes in this. Top box is 5*5*5
    top = MDEventsTestHelper::makeRecursiveMDGridBox<3>(5, 2);
  }

public:
  // ---------------------------------------------------------------
  /** Make a simple iterator that will go through all the boxes */
  void do_test_iterator(bool leafOnly, bool ImplicitFunction, size_t expected) {
    // Count the top level box.
    size_t counter = 1;
    MDBoxBase<MDLeanEvent<3>, 3> *box = nullptr;

    MDBoxImplicitFunction *function = nullptr;
    if (ImplicitFunction) {
      std::vector<coord_t> min(3, 2.001f);
      std::vector<coord_t> max(3, 2.999f);
      function = new MDBoxImplicitFunction(min, max);
    }

    MDBoxIterator<MDLeanEvent<3>, 3> it(top, 20, leafOnly, new SkipNothing,
                                        function);

    // Count all of them
    while (it.next()) {
      box = it.getBox();
      counter++;
    }
    TS_ASSERT(box);
    TS_ASSERT_EQUALS(counter, expected);
  }

  void test_iterator() {
    do_test_iterator(false, false, 125 * 125 * 125 + 125 * 125 + 125 + 1);
  }

  void test_iterator_leafOnly() {
    do_test_iterator(true, false, 125 * 125 * 125);
  }

  void test_iterator_withImplicitFunction() {
    do_test_iterator(false, true, 1 + 125 * 125 + 125 + 1);
  }

  void test_iterator_withImplicitFunction_leafOnly() {
    do_test_iterator(true, true, 125 * 125);
  }

  // ---------------------------------------------------------------
  /** This iterator will also take the boxes and fill
   * a vector with them; this is a full speed comparison to getBoxes()
   * which directly returns that vector, if that happens to be what you need.*/
  void do_test_iterator_that_fills_a_vector(bool leafOnly) {
    MDBoxBase<MDLeanEvent<3>, 3> *box;
    MDBoxIterator<MDLeanEvent<3>, 3> it(top, 20, leafOnly, new SkipNothing);
    std::vector<MDBoxBase<MDLeanEvent<3>, 3> *> boxes;

    // Iterate and fill the vector as you go.
    boxes.emplace_back(it.getBox());
    while (it.next()) {
      box = it.getBox();
      boxes.emplace_back(box);
    }
    TS_ASSERT(box);
    size_t expected = 125 * 125 * 125 + 125 * 125 + 125 + 1;
    if (leafOnly)
      expected = 125 * 125 * 125;
    TS_ASSERT_EQUALS(boxes.size(), expected);
  }

  void test_iterator_that_fills_a_vector() {
    do_test_iterator_that_fills_a_vector(false);
  }

  void test_iterator_that_fills_a_vector_leafOnly() {
    do_test_iterator_that_fills_a_vector(true);
  }

  // ---------------------------------------------------------------
  /** For comparison, let's use getBoxes() that fills a vector directly.
   * After that, we iterate through them to compare how long the whole operation
   * takes.
   */
  void do_test_getBoxes(bool leafOnly, int ImplicitFunction, size_t expected) {
    std::vector<API::IMDNode *> boxes;

    MDImplicitFunction *function = nullptr;
    if (ImplicitFunction == 1) {
      // Box in 3D where 2 < (x,y,z) < 3
      std::vector<coord_t> min(3, 2.001f);
      std::vector<coord_t> max(3, 2.999f);
      function = new MDBoxImplicitFunction(min, max);
      top->getBoxes(boxes, 20, leafOnly, function);
    } else if (ImplicitFunction == 2) {
      // Plane defining 2.2 < x < 2.4
      function = new MDImplicitFunction();
      coord_t normal1[3] = {+1.000f, 0, 0};
      coord_t origin1[3] = {+2.201f, 0, 0};
      function->addPlane(MDPlane(3, normal1, origin1));
      coord_t normal2[3] = {-1.000f, 0, 0};
      coord_t origin2[3] = {+2.399f, 0, 0};
      function->addPlane(MDPlane(3, normal2, origin2));
      top->getBoxes(boxes, 20, leafOnly, function);
    } else if (ImplicitFunction == 3) {
      // Box in 3D where -5 < (x,y,z) < +10
      std::vector<coord_t> min(3, -4.999f);
      std::vector<coord_t> max(3, +9.999f);
      function = new MDBoxImplicitFunction(min, max);
      top->getBoxes(boxes, 20, leafOnly, function);
    } else {
      top->getBoxes(boxes, 20, leafOnly);
    }
    TS_ASSERT_EQUALS(boxes.size(), expected);

    // Now we still need to iterate through the vector to do anything, so this
    // is a more fair comparison
    size_t counter = 0;
    for (const auto &box : boxes) {
      (void)box;
      ++counter;
    }

    TS_ASSERT_EQUALS(counter, expected);
  }

  void test_getBoxes() {
    do_test_getBoxes(false, 0, 125 * 125 * 125 + 125 * 125 + 125 + 1);
  }

  void test_getBoxes_leafOnly() { do_test_getBoxes(true, 0, 125 * 125 * 125); }

  void test_getBoxes_withImplicitFunction() {
    do_test_getBoxes(false, 1, 1 + 125 * 125 + 125 + 1);
  }

  void test_getBoxes_withImplicitFunction_leafOnly() {
    do_test_getBoxes(true, 1, 125 * 125);
  }

  void test_getBoxes_withPlaneImplicitFunction() {
    do_test_getBoxes(true, 2, 125 * 125 * 125 / 25);
  }

  void test_getBoxes_withHugeImplicitFunction() {
    do_test_getBoxes(true, 3, 125 * 125 * 125);
  }
};
#undef RUN_CXX_PERFORMANCE_TEST_EMBEDDED