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Simplifying test case.

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This commit is contained in:
Barry Revzin 2020-08-18 09:12:52 -05:00
parent a504d3f6fc
commit ba54c9f69a
1 changed files with 9 additions and 18 deletions
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27
test/format-test.cc
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@ -2474,36 +2474,27 @@ TEST(FormatTest, FormatUTF8Precision) {
EXPECT_EQ(from_u8str(result), from_u8str(str.substr(0, 5)));
}
#ifdef __cpp_decltype_auto
struct lazy_optional {
bool engaged;
std::string value;
};
struct check_back_appender {};
FMT_BEGIN_NAMESPACE
template <> struct formatter<lazy_optional> {
template <> struct formatter<check_back_appender> {
template <typename ParseContext>
auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
return ctx.begin();
}
template <typename Context>
auto format(const lazy_optional& opt, Context& ctx) {
if (opt.engaged) {
auto out = format_to(ctx.out(), "Some(");
out = format_to(out, "{}", opt.value);
*out = ')';
return ++out;
} else {
return format_to(ctx.out(), "None()");
}
auto format(check_back_appender, Context& ctx) -> decltype(ctx.out()) {
// needs to satisfy weakly_incrementable
auto out = ctx.out();
static_assert(std::is_same<decltype(++out), decltype(out)&>::value);
*out = 'y';
return ++out;
}
};
FMT_END_NAMESPACE
TEST(FormatTest, BackInsertSlicing) {
EXPECT_EQ(fmt::format("{}", lazy_optional{false, ""}), "None()");
EXPECT_EQ(fmt::format("{}", lazy_optional{true, "X"}), "Some(X)");
EXPECT_EQ(fmt::format("{}", check_back_appender{}), "y");
}
#endif