### Question:
PrometheusTimestampDeserializer extends JsonDeserializer<Instant> { static Instant decimalEpochTimestampToSQLTimestamp(String timestamp) { long promTimestampMillis = (long) (Double.parseDouble(timestamp) * 1000); return ofEpochMilli(promTimestampMillis); }  @Override Instant deserialize(JsonParser jsonParser, DeserializationContext context);  }### Answer:
@Test public void testDeserializeTimestamp() { Instant now = Instant.now(); long nowEpochMillis = now.toEpochMilli(); String nowTimeStr = PrometheusSplitManager.decimalSecondString(nowEpochMillis); Instant nowTimestampActual = PrometheusTimestampDeserializer.decimalEpochTimestampToSQLTimestamp(nowTimeStr); assertEquals(nowTimestampActual, now.truncatedTo(MILLIS)); }