Update tz validation test with more checking

test/tz_test/validate.cpp

@@ -1,6 +1,83 @@
 #include "tz.h"
 #include <iostream>
 
+void
+test_info(const date::Zone* zone, const date::Info& info)
+{
+    using namespace date;
+    using namespace std::chrono;
+    auto begin = info.begin;
+    auto end = info.end - microseconds{1};
+    auto mid = begin + (end - begin) /2 ;
+
+    if (begin > day_point{jan/1/1700})
+    {
+        auto local = zone->to_local(begin).first;
+        auto prev_local = zone->to_local(begin - seconds{1}).first;
+        if (prev_local < local - seconds{1})
+        {
+            assert(zone->to_sys(local) == begin);
+            auto imaginary = prev_local + (local - seconds{1} - prev_local) / 2;
+            try
+            {
+                zone->to_sys(imaginary);
+                assert(false);
+            }
+            catch (const nonexistent_local_time&)
+            {
+            }
+        }
+        else if (prev_local > local - seconds{1})
+        {
+            auto ambiguous = local - seconds{1} +
+                             (prev_local - (local - seconds{1})) / 2;
+            try
+            {
+                zone->to_sys(ambiguous);
+                assert(false);
+            }
+            catch (const ambiguous_local_time&)
+            {
+            }
+        }
+    }
+
+    auto local = zone->to_local(mid).first;
+    assert(zone->to_sys(local) == mid);
+
+    if (end < day_point{jan/1/3000})
+    {
+        auto local = zone->to_local(end).first;
+        auto next_local = zone->to_local(info.end).first;
+        if (next_local < local + microseconds{1})
+        {
+            auto ambiguous = next_local + (local + microseconds{1} - next_local) / 2;
+            try
+            {
+                zone->to_sys(ambiguous);
+                assert(false);
+            }
+            catch (const ambiguous_local_time&)
+            {
+            }
+        }
+        else if (next_local > local + microseconds{1})
+        {
+            assert(zone->to_sys(local) == end);
+            auto imaginary = local + microseconds{1} +
+                             (next_local - (local + microseconds{1})) / 2;
+            try
+            {
+                zone->to_sys(imaginary);
+                assert(false);
+            }
+            catch (const nonexistent_local_time&)
+            {
+            }
+        }
+    }
+}
+
 int
 main()
 {
@@ -14,6 +91,7 @@ main()
     for (auto& link : db.links)
         names.push_back(link.name());
     std::sort(names.begin(), names.end());
+    std::cout << db.version << "\n\n";
     for (auto const& name : names)
     {
         std::cout << name << '\n';
@@ -30,12 +108,14 @@ main()
         else
             std::cout << " daylight ";
         std::cout << info.abbrev << '\n';
+        test_info(z, info);
         auto prev_offset = info.offset;
         auto prev_abbrev = info.abbrev;
         auto prev_save = info.save;
         for (begin = info.end; begin < end; begin = info.end)
         {
             info = z->get_info(begin, tz::utc);
+            test_info(z, info);
             if (info.offset == prev_offset && info.abbrev == prev_abbrev &&
                     info.save == prev_save)
                 continue;