refactor: move Boost datetime usage to wallet

This means we don't need datetime in a --disable-wallet build, and it
isn't included in the kernel.

src/wallet/test/fuzz/parse_iso8601.cpp

@@ -0,0 +1,34 @@
+// Copyright (c) 2019-2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <util/time.h>
+#include <wallet/rpc/util.h>
+
+#include <cassert>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+FUZZ_TARGET(parse_iso8601)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+
+    const int64_t random_time = fuzzed_data_provider.ConsumeIntegral<int32_t>();
+    const std::string random_string = fuzzed_data_provider.ConsumeRemainingBytesAsString();
+
+    const std::string iso8601_datetime = FormatISO8601DateTime(random_time);
+    (void)FormatISO8601Date(random_time);
+    const int64_t parsed_time_1 = wallet::ParseISO8601DateTime(iso8601_datetime);
+    if (random_time >= 0) {
+        assert(parsed_time_1 >= 0);
+        if (iso8601_datetime.length() == 20) {
+            assert(parsed_time_1 == random_time);
+        }
+    }
+
+    const int64_t parsed_time_2 = wallet::ParseISO8601DateTime(random_string);
+    assert(parsed_time_2 >= 0);
+}

src/wallet/test/rpc_util_tests.cpp

@@ -0,0 +1,24 @@
+// Copyright (c) 2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <wallet/rpc/util.h>
+
+#include <boost/test/unit_test.hpp>
+
+namespace wallet {
+
+BOOST_AUTO_TEST_SUITE(wallet_util_tests)
+
+BOOST_AUTO_TEST_CASE(util_ParseISO8601DateTime)
+{
+    BOOST_CHECK_EQUAL(ParseISO8601DateTime("1970-01-01T00:00:00Z"), 0);
+    BOOST_CHECK_EQUAL(ParseISO8601DateTime("1960-01-01T00:00:00Z"), 0);
+    BOOST_CHECK_EQUAL(ParseISO8601DateTime("2000-01-01T00:00:01Z"), 946684801);
+    BOOST_CHECK_EQUAL(ParseISO8601DateTime("2011-09-30T23:36:17Z"), 1317425777);
+    BOOST_CHECK_EQUAL(ParseISO8601DateTime("2100-12-31T23:59:59Z"), 4133980799);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace wallet