cpp-useful-iterators/filter_iterator.t.h

//
//  filter_iterator.t.h
//  iterator
//
//  Created by Sam Jaffe on 6/17/17.
//

#pragma once

#include <cxxtest/TestSuite.h>

#include "filter_iterator.hpp"

class filter_iterator_TestSuite : public CxxTest::TestSuite {
public:
  void test_returns_subset() {
    int data[] = { 1, 2, 3, 4, 5 };
    auto pred = [](int i) { return i%2 == 0; };
    auto it = make_filter_iterator(pred, data);
    decltype(it) end = {};
    TS_ASSERT_EQUALS(std::distance(it, end), 2);
    TS_ASSERT_EQUALS(*it++, 2);
    TS_ASSERT_EQUALS(*it++, 4);
  }
  
  void test_no_matches_marks_end() {
    int data[] = { 1, 3, 5 };
    auto pred = [](int i) { return i%2 == 0; };
    auto it = make_filter_iterator(pred, data);
    decltype(it) end = {};
    TS_ASSERT_EQUALS(it, end);
  }
  
  void test_cannot_advance_past_end() {
    int data[] = { 1, 2, 3, 4, 5 };
    auto pred = [](int i) { return i%2 == 0; };
    auto it = make_filter_iterator(pred, data);
    decltype(it) end = {};
    ++++it;
    TS_ASSERT_EQUALS(it, end);
    ++it;
    TS_ASSERT_EQUALS(it, end);
  }
};