feat(wcs): add shared domain contracts

ruoyi-wcs/src/test/java/com/ruoyi/wcs/domain/shared/SharedContractsTest.java

@@ -0,0 +1,36 @@
+package com.ruoyi.wcs.domain.shared;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.Instant;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class SharedContractsTest {
+
+    @Test
+    void rejectsBlankEventIdentity() {
+        assertThrows(IllegalArgumentException.class, () ->
+                new DomainEvent("", "ORDER-1", 1L, Instant.EPOCH, "OrderAccepted"));
+    }
+
+    @Test
+    void rejectsInvalidEventSequence() {
+        assertThrows(IllegalArgumentException.class, () ->
+                new DomainEvent("E-1", "ORDER-1", 0L, Instant.EPOCH, "OrderAccepted"));
+    }
+
+    @Test
+    void exposesDeterministicEventFields() {
+        Instant occurredAt = Instant.parse("2026-08-04T00:00:00Z");
+        DomainEvent event = new DomainEvent("E-1", "ORDER-1", 2L,
+                occurredAt, "OrderPlanned");
+
+        assertEquals("E-1", event.getEventId());
+        assertEquals("ORDER-1", event.getAggregateId());
+        assertEquals(2L, event.getSequence());
+        assertEquals(occurredAt, event.getOccurredAt());
+        assertEquals("OrderPlanned", event.getType());
+    }
+}