Make conversion of Option to bool stricter

[johnomotani]

Previously, Options::as<bool>() only tested (case-insensitively) if first character was 'n', 'f', '0', 'y', 't', or '1'. Now only allow (still case-insensitively but checking full strings) 'n', 'no', 'f', 'false', '0', 'y', 'yes', 't', 'true', or '1'. See discussion on boutproject/boutdata#32.

I found a nice intro to parameterised tests here https://www.sandordargo.com/blog/2019/04/24/parameterized-testing-with-gtest, which I used for the unit tests.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[ZedThree]

Tests are failing because we check the old behaviour:

BOUT-dev/tests/unit/sys/test_options.cxx

Lines 293 to 296 in b5e2c32

	// Surprise true
	options.set("bool_key3", "yes_this_is_a_bool", "code2");
	EXPECT_NO_THROW(options.get("bool_key3", value3, false, false));
	EXPECT_EQ(value3, true);

Deleting those lines should be sufficient

[ZedThree]

Just for my own curiosity, I had a stab at rewriting this to avoid the long-ish chain of comparisons, but I think this is probably worse:

auto one_of = [&strvalue](const std::vector<std::string>& values) -> bool {
  return std::any_of(
      values.begin(), values.end(),
      [&strvalue](const auto& value) { return value == strvalue; });
};
if (one_of({"y", "yes", "t", "true", "1"})) {
  result = true;
} else if (one_of({"n", "no", "f", "false", "0"})) {
  result = false;
} else {

Could be worth if it one_of were a function we could reuse somewhere else.

I think it just betrays my love of lambdas and C++'s love of verbose grammar. Here it is in Python:

if strvalue.lower() in ["y", "yes", "t", "true", "1"]:
  result = True
elif if strvalue.lower() in ["n", "no", "f", "false", "0"]:
   result = False
else:
   raise ValueError()

[ZedThree]

Looks good, thanks @johnomotani !