Merge bitcoin/bitcoin#29872: test: Add missing Assert(mock_time_in >= 0s) to SetMockTime

fae0db5 refactor: Use chrono type for g_mock_time (MarcoFalke)
fa382d3 test: Add missing Assert(mock_time_in >= 0s) to SetMockTime (MarcoFalke)

Pull request description:

  Seems odd to have the assert in the *deprecated* function, but not in the other.

  Fix this by adding it to the other, and by inlining the deprecated one.

  Also, use chrono type for the global mocktime variable.

ACKs for top commit:
  davidgumberg:
    crACK bitcoin/bitcoin@fae0db5
  stickies-v:
    ACK fae0db5

Tree-SHA512: 630c2917422ff2a7fa307114f95f22ad3c205429ffe36e67f0b2650733e40c876289c1aecebe882a9123d3106db7606bd6eff067ed6e2ecb95765984d3fe8612

Author: fanquake

src/util/time.cpp

@@ -16,11 +16,11 @@
 
 void UninterruptibleSleep(const std::chrono::microseconds& n) { std::this_thread::sleep_for(n); }
 
-static std::atomic<int64_t> nMockTime(0); //!< For testing
+static std::atomic<std::chrono::seconds> g_mock_time{}; //!< For testing
 
 NodeClock::time_point NodeClock::now() noexcept
 {
-    const std::chrono::seconds mocktime{nMockTime.load(std::memory_order_relaxed)};
+    const auto mocktime{g_mock_time.load(std::memory_order_relaxed)};
     const auto ret{
         mocktime.count() ?
             mocktime :
@@ -29,20 +29,16 @@ NodeClock::time_point NodeClock::now() noexcept
     return time_point{ret};
 };
 
-void SetMockTime(int64_t nMockTimeIn)
-{
-    Assert(nMockTimeIn >= 0);
-    nMockTime.store(nMockTimeIn, std::memory_order_relaxed);
-}
-
+void SetMockTime(int64_t nMockTimeIn) { SetMockTime(std::chrono::seconds{nMockTimeIn}); }
 void SetMockTime(std::chrono::seconds mock_time_in)
 {
-    nMockTime.store(mock_time_in.count(), std::memory_order_relaxed);
+    Assert(mock_time_in >= 0s);
+    g_mock_time.store(mock_time_in, std::memory_order_relaxed);
 }
 
 std::chrono::seconds GetMockTime()
 {
-    return std::chrono::seconds(nMockTime.load(std::memory_order_relaxed));
+    return g_mock_time.load(std::memory_order_relaxed);
 }
 
 int64_t GetTime() { return GetTime<std::chrono::seconds>().count(); }