cpp-optional-stream/optional_stream.t.h

//
//  optional_stream.t.h
//  optional.stream
//
//  Created by Sam Jaffe on 1/29/17.
//

#pragma once

#include <cxxtest/TestSuite.h>

#include "optional_stream.hpp"

class optional_stream_TestSuite : public CxxTest::TestSuite {
public:
  void test_optional_processes_real() {
    auto strm = stream::optional::make_stream(5);
    auto plus2 = [](int i) { return i+2; };
    std::optional<int> out = strm.map(plus2);
    TS_ASSERT(out);
    TS_ASSERT_EQUALS(*out, 7);
  }
  
  void test_optional_ignores_fake() {
    auto strm = stream::optional::make_stream<int>();
    auto fail = [](int i) { TS_FAIL("Expected Empty"); return i; };
    std::optional<int> out = strm.map(fail);
    TS_ASSERT(!out);
  }
  
  void test_optional_flatmap_can_become_empty() {
    auto strm = stream::optional::make_stream(5);
    auto discard_odd = [](int i) { return i%2==0? std::optional<int>(i) : std::nullopt; };
    std::optional<int> out = strm.flatmap(discard_odd);
    TS_ASSERT(!out);
  }

  void test_optional_flatmap_can_remain_exists() {
    auto strm = stream::optional::make_stream(6);
    auto discard_odd = [](int i) { return i%2==0? std::optional<int>(i) : std::nullopt; };
    std::optional<int> out = strm.flatmap(discard_odd);
    TS_ASSERT(out);
    TS_ASSERT_EQUALS(*out, 6);
  }
};