CXX-1371 Pass b_timestamp fields to bson_append_timestamp in correct order

Author: saghm

src/bsoncxx/builder/core.cpp

@@ -333,8 +333,8 @@ void core::append(const types::b_int32& value) {
 void core::append(const types::b_timestamp& value) {
     stdx::string_view key = _impl->next_key();
 
-    bson_append_timestamp(_impl->back(), key.data(), key.length(), value.increment,
-                          value.timestamp);
+    bson_append_timestamp(_impl->back(), key.data(), static_cast<std::int32_t>(key.length()),
+                          value.timestamp, value.increment);
 }
 
 void core::append(const types::b_int64& value) {

src/bsoncxx/test/bson_builder.cpp

@@ -337,13 +337,13 @@ TEST_CASE("builder appends int32", "[bsoncxx::builder::stream]") {
 }
 
 TEST_CASE("builder appends timestamp", "[bsoncxx::builder::stream]") {
-    bson_t expected;
-    bson_init(&expected);
     builder::stream::document b;
+    types::b_timestamp foo{100, 1000};
+    b << "foo" << foo;
 
-    bson_append_timestamp(&expected, "foo", -1, 100, 1000);
-
-    b << "foo" << types::b_timestamp{100, 1000};
+    bson_t expected;
+    bson_init(&expected);
+    bson_append_timestamp(&expected, "foo", -1, foo.timestamp, foo.increment);
 
     bson_eq_stream(&expected, b);