Greeter

//
// pch.h
//
#pragma once
#include <codeanalysis\warnings.h>
#pragma warning(push)
#pragma warning(disable : ALL_CODE_ANALYSIS_WARNINGS)
#include "gtest/gtest.h"
#pragma warning(pop)
#include <algorithm>
#include <chrono>
#include <iostream>
#include <string>
#include <string_view>
//
//
//

//test.cpp
#include "pch.h"
using namespace std::chrono;
using namespace std::string_view_literals;
using namespace std::string_literals;
using std::string_view;
using TimeOfDay = int;
constexpr string_view WHITE_SPACE = " \f\n\r\t\v"sv;

constexpr string_view trimLeft(string_view in,
                               string_view delims = WHITE_SPACE) noexcept {
  const auto countFromTheLeft = in.find_first_not_of(delims);
  if (countFromTheLeft != in.npos) {
    in.remove_prefix(countFromTheLeft);
  }
  return in;
};
constexpr string_view trimRight(string_view in,
                                string_view delims = WHITE_SPACE) noexcept {
  const auto lastValidPos = in.find_last_not_of(delims);
  const auto countFromTheRight = in.size() - lastValidPos - 1;
  in.remove_suffix(countFromTheRight);
  return in;
};
constexpr string_view trim(string_view in,
                           string_view delims = WHITE_SPACE) noexcept {
  return trimRight(trimLeft(in, delims), delims);
}

constexpr std::string to_string(string_view s) { return std::string(s); }

constexpr std::string capitalize(std::string s) {
  if (s.empty()) {
    return s;
  }
  s[0] = static_cast<char>(std::toupper(static_cast<unsigned char>(s[0])));
  return s;
}

constexpr bool isBetween(TimeOfDay in, TimeOfDay min, TimeOfDay max) noexcept {
  return in >= min && in <= max;
}
constexpr bool isMorning(TimeOfDay in) noexcept { return isBetween(in, 6, 12); }
constexpr bool isEvening(TimeOfDay in) noexcept {
  return isBetween(in, 18, 22);
}
constexpr bool isNight(TimeOfDay in) noexcept {
  return isBetween(in, 22, 24) || isBetween(in, 0, 6);
}

constexpr std::string_view getGreetingFor(TimeOfDay time) noexcept {
  if (isMorning(time)) {
    return "Good morning "sv;
  }
  if (isEvening(time)) {
    return "Good evening "sv;
  }
  if (isNight(time)) {
    return "Good night "sv;
  }
  return "Hello "sv;
}

struct Greeter {
  constexpr void time(TimeOfDay time) noexcept { _time = time; }
  constexpr TimeOfDay time() const noexcept { return _time; }

  constexpr std::string greet(string_view name) {
    const auto clean_name = to_string(trim(name));
    const auto greeting = to_string(getGreetingFor(time()));
    return greeting + capitalize(clean_name);
  }

private:
  TimeOfDay _time = TimeOfDay(14);
};

TEST(Greeter, canReturnInput) {
  Greeter g;
  EXPECT_EQ(g.greet("Ulf"), "Hello Ulf");
}

TEST(Greeter, canTrimInput) {
  Greeter g;
  EXPECT_EQ(g.greet("   Ulf    "), "Hello Ulf");
}

TEST(Greeter, canCapitalizeFirst) {
  Greeter g;
  EXPECT_EQ(g.greet("   ulf    "), "Hello Ulf");
}

TEST(Greeter, saysGoodMorningInTheMorning) {
  Greeter g;
  g.time(11);
  EXPECT_EQ(g.greet("   ulf    "), "Good morning Ulf");
}

TEST(Greeter, saysGoodEveningInTheEvening) {
  Greeter g;
  g.time(20);
  EXPECT_EQ(g.greet("   ulf    "), "Good evening Ulf");
}

TEST(Greeter, saysGoodNightAtNight) {
  Greeter g;
  g.time(2);
  EXPECT_EQ(g.greet("   ulf    "), "Good night Ulf");
}

constexpr auto clean = "foo"sv;
constexpr auto whitespace_left = "     foo"sv;
constexpr auto whitespace_right = "foo     "sv;

TEST(trim, canTrimLeft) {
  EXPECT_EQ(trim(whitespace_left), clean);
  EXPECT_EQ(trimLeft(whitespace_right),
            whitespace_right); // don't touch the right side
}
TEST(trim, canTrimEmpty) {
  EXPECT_EQ(trimLeft(""), ""sv);
  EXPECT_EQ(trimRight(""), ""sv);
  EXPECT_EQ(trim(""), ""sv);
}

TEST(trim, canTrimPreTrimmed) {
  EXPECT_EQ(trim(clean), clean);
  EXPECT_EQ(trimRight(clean), clean);
  EXPECT_EQ(trimLeft(clean), clean);
}
TEST(trim, canTrimRight) {
  EXPECT_EQ(trim(whitespace_right), clean);
  EXPECT_EQ(trimRight(whitespace_left),
            whitespace_left); // don't touch the left side
}

TEST(trim, canTrimBoth) {
  string_view input = "      foo     "sv;
  EXPECT_EQ(trim(input), clean);
}

TEST(trim, canTrimWithSpaceInMiddle) {
  string_view input = "      f o o b a r     "sv;
  EXPECT_EQ(trim(input), "f o o b a r"sv);

  string_view notrim = "f o o b a r"sv;
  EXPECT_EQ(trim(notrim), "f o o b a r"sv);
}