Improve 1384 test case

Author: ckormanyos

test/github_issue_1384.cpp

@@ -11,9 +11,13 @@
 namespace boost {
 namespace log {
 
-auto do_something() -> void
-{
-}
+auto do_something() -> void;
+
+// The presence of this namespace-local subroutine itself conflicted
+// (at the time of the issue) with Boost.Log. So this behavior is
+// simulated here.
+
+auto do_something() -> void { } // LCOV_EXCL_LINE
 
 } // namespace log
 } // namespace boost
@@ -24,15 +28,24 @@ auto main() -> int;
 
 auto main() -> int
 {
+  boost::log::do_something(); // LCOV_EXCL_LINE
+
   using local_decimal_type = boost::decimal::decimal64_t;
 
-  const local_decimal_type arg_dec { 1.23456 };
+  const local_decimal_type arg_dec { 123456, -5 };
 
+  // N[ArcCosh[123456/100000], 20]
   const local_decimal_type result1 { acosh(arg_dec) };
+
+  // N[Log[Gamma[123456/100000]], 20]
   const local_decimal_type result2 { lgamma(arg_dec) };
 
-  BOOST_TEST(result1 > local_decimal_type { 0.0 });
-  BOOST_TEST(result2 < local_decimal_type { 0.0 });
+  // N[Zeta[123456/10000], 20]
+  const local_decimal_type result3 { riemann_zeta(arg_dec * local_decimal_type { 10.0 }) };
+
+  BOOST_TEST(result1 > local_decimal_type { 0.0 }); // 0.67219624862864254285
+  BOOST_TEST(result2 < local_decimal_type { 0.0 }); // -0.094616414889227312801
+  BOOST_TEST(result3 > local_decimal_type { 1.0 }); // 1.0001934607133929720
 
   return boost::report_errors();
 }