cpp-string-utils/test/cast_test.cxx

//
//  cast_test.cxx
//  string_utils-test
//
//  Created by Sam Jaffe on 2/14/21.
//  Copyright © 2021 Sam Jaffe. All rights reserved.
//

#include "string_utils/cast.h"

#include "xcode_gtest_helper.h"

using testing::ElementsAre;
using testing::FieldsAre;
using testing::Pair;
using namespace string_utils;

TEST(CastIntegerTest, CastsWithBase10) {
  auto [value, success] = cast<int>("10");
  EXPECT_TRUE(success);
  EXPECT_THAT(value, 10);
}

TEST(CastIntegerTest, DoesNotCastBase8) {
  auto [value, success] = cast<int>("010");
  EXPECT_TRUE(success);
  EXPECT_THAT(value, 10);
}

TEST(CastIntegerTest, DoesNotCastHex) {
  auto [value, success] = cast<int>("0x10");
  EXPECT_FALSE(success);
  EXPECT_THAT(value, 0);
}

TEST(CastIntegerTest, FailsOnBadData) {
  auto [value, success] = cast<int>("x");
  EXPECT_FALSE(success);
  EXPECT_THAT(value, 0);
}

TEST(CastIntegerTest, FailsOnBadSuffix) {
  auto [value, success] = cast<int>("10x");
  EXPECT_FALSE(success);
  EXPECT_THAT(value, 10);
}

TEST(CastIntegerTest, FailsOnOutOfBounds) {
  auto [_, success] = cast<int>("2147483648");
  EXPECT_FALSE(success);
}

TEST(CastBooleanTest, CastsVariousTrueValues) {
  EXPECT_THAT(cast<bool>("true"), Pair(true, true));
  EXPECT_THAT(cast<bool>("TRUE"), Pair(true, true));
  EXPECT_THAT(cast<bool>("YES"), Pair(true, true));
  EXPECT_THAT(cast<bool>("1"), Pair(true, true));
}

TEST(CastBooleanTest, CastsVariousFalseValues) {
  EXPECT_THAT(cast<bool>("false"), Pair(false, true));
  EXPECT_THAT(cast<bool>("FALSE"), Pair(false, true));
  EXPECT_THAT(cast<bool>("NO"), Pair(false, true));
  EXPECT_THAT(cast<bool>("0"), Pair(false, true));
}

TEST(CastBooleanTest, DoesNotCastAllIntegers) {
  auto [_, success] = cast<bool>("2");
  EXPECT_FALSE(success);
}

MATCHER_P(HoldsAlternative, typearg,
          std::string("holds a value of type ") + typeid(typearg).name()) {
  using T = std::remove_const_t<std::decay_t<decltype(typearg)>>;
  return std::holds_alternative<T>(arg);
}

template <typename T> auto HoldsAlternative() { return HoldsAlternative(T()); }

TEST(CastVariantTest, StringVariantWillAlwaysMatchWhenEncountered) {
  auto [value, success] = cast<std::variant<std::string, int>>("2");
  EXPECT_THAT(value, HoldsAlternative<std::string>());
}

TEST(CastVariantTest, EvaluatesTypesLeftToRight) {
  auto [value, success] = cast<std::variant<int, std::string>>("2");
  EXPECT_THAT(value, HoldsAlternative<int>());
}

using pair_t = std::pair<std::string, std::string>;
using tuple_t = std::tuple<int, int, std::string>;

TEST(CastKeyValTest, FailsOnTooFewTokens) {
  auto [value, success] = cast<pair_t>(std::vector{"key"});
  EXPECT_FALSE(success);
}

TEST(CastKeyValTest, ParsesTokens) {
  auto [value, success] = cast<pair_t>(std::vector{"key", "value"});
  EXPECT_TRUE(success);
  EXPECT_THAT(value, Pair("key", "value"));
}

TEST(CastKeyValTest, FailsOnTooManyTokens) {
  auto [value, success] = cast<pair_t>(std::vector{"key", "value", "mapping"});
  EXPECT_FALSE(success);
}

TEST(CastTupleTest, FailsOnTooFewTokens) {
  auto [value, success] = cast<tuple_t>(std::vector{"0", "A"});
  EXPECT_FALSE(success);
}

TEST(CastTupleTest, FailsOnTooManyTokens) {
  auto [value, success] = cast<tuple_t>(std::vector{"0", "1", "A", "B"});
  EXPECT_FALSE(success);
}

TEST(CastTupleTest, ParsesIfAllGood) {
  auto [value, success] = cast<tuple_t>(std::vector{"0", "1", "A"});
  EXPECT_TRUE(success);
  EXPECT_THAT(value, FieldsAre(0, 1, "A"));
}

TEST(CastTupleTest, FailsOnAnyParseError) {
  auto [value, success] = cast<tuple_t>(std::vector{"0", "Q", "A"});
  EXPECT_FALSE(success);
}

struct Bindable {
  int a;
  std::string b;
};

bool cast(Bindable & out, std::vector<std::string_view> const & strs) {
  return strs.size() == 2 && cast(out.a, strs[0]) && cast(out.b, strs[1]);
}

struct Positive {
  int value;
};

bool cast(Positive & out, std::string_view str) {
  return cast(out.value, str) && out.value > 0;
}

TEST(CastTest, UsesADL) {
  auto [value, success] = cast<Bindable>(std::vector{"0", "Q"});
  EXPECT_TRUE(success);
}

TEST(CastTest, CanImposeConstraint) {
  auto [value, success] = cast<Positive>("0");
  EXPECT_FALSE(success);
}

TEST(CastContainerTest, CanCastVector) {
  auto [value, success] =
      cast<std::vector<std::string>>(std::vector{"0", "Q", "A"});
  EXPECT_TRUE(success);
  EXPECT_THAT(value, ElementsAre("0", "Q", "A"));
}

TEST(CastContainerTest, FailsIfBadValueCast) {
  auto [value, success] = cast<std::vector<int>>(std::vector{"0", "Q", "A"});
  EXPECT_FALSE(success);
}

TEST(CastContainerTest, CanCastSet) {
  auto [value, success] =
      cast<std::set<std::string>>(std::vector{"0", "0", "A"});
  EXPECT_TRUE(success);
  EXPECT_THAT(value, ElementsAre("0", "A"));
}

TEST(CastContainerTest, CanCastMap) {
  auto [value, success] = cast<std::map<std::string, std::string>>(
      std::vector{"0=1", "0=2", "A=B"});
  EXPECT_TRUE(success);
  EXPECT_THAT(value, ElementsAre(Pair("0", "1"), Pair("A", "B")));
}

TEST(CastContainerTest, FailsIfBadCastOnKey) {
  auto [value, success] =
      cast<std::map<int, std::string>>(std::vector{"0=1", "0=2", "A=B"});
  EXPECT_FALSE(success);
}

TEST(CastContainerTest, FailsIfBadCastOnValue) {
  auto [value, success] =
      cast<std::map<std::string, int>>(std::vector{"0=1", "0=2", "A=B"});
  EXPECT_FALSE(success);
}