test(cdc): reproduce connector registration authority gap on current develop

cdc-service/src/test/java/com/xtrmetl/cdc/spi/CdcRegistryIdentityTest.java

@@ -0,0 +1,105 @@
+package com.xtrmetl.cdc.spi;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Fail-first contract for CDC connector registration authority.
+ *
+ * <p>Connector identifiers select production implementations. Invalid registration must fail before
+ * registry mutation so bean order or plugin code cannot silently replace or remove that authority.</p>
+ */
+class CdcRegistryIdentityTest {
+
+    @Test
+    void duplicateSourceConnectorIdsFailClosedInsteadOfReplacingRegistration() {
+        CdcSourceConnector first = source("duplicate-source");
+        CdcSourceConnector second = source("duplicate-source");
+
+        IllegalArgumentException failure = assertThrows(
+                IllegalArgumentException.class,
+                () -> new CdcSourceRegistry(List.of(first, second))
+        );
+
+        assertEquals("Duplicate CDC source connector id: duplicate-source", failure.getMessage());
+    }
+
+    @Test
+    void duplicateTargetConnectorIdsFailClosedInsteadOfReplacingRegistration() {
+        CdcTargetRegistry registry = new CdcTargetRegistry();
+        CdcTargetConnector duplicateKafka = target(KafkaCdcTargetConnector.ID);
+
+        IllegalArgumentException failure = assertThrows(
+                IllegalArgumentException.class,
+                () -> registry.register(duplicateKafka)
+        );
+
+        assertEquals("Duplicate CDC target connector id: kafka", failure.getMessage());
+    }
+
+    @Test
+    void nullSourceConnectorFailsBeforeRegistryMutation() {
+        CdcSourceRegistry registry = new CdcSourceRegistry();
+        IllegalArgumentException failure = assertThrows(IllegalArgumentException.class, () -> registry.register(null));
+        assertEquals("CDC source connector must not be null", failure.getMessage());
+    }
+
+    @Test
+    void nullTargetConnectorFailsBeforeRegistryMutation() {
+        CdcTargetRegistry registry = new CdcTargetRegistry();
+        IllegalArgumentException failure = assertThrows(IllegalArgumentException.class, () -> registry.register(null));
+        assertEquals("CDC target connector must not be null", failure.getMessage());
+    }
+
+    @Test
+    void blankSourceConnectorIdFailsBeforeRegistryMutation() {
+        CdcSourceConnector blank = source("   ");
+        IllegalArgumentException failure = assertThrows(
+                IllegalArgumentException.class,
+                () -> new CdcSourceRegistry(List.of(blank))
+        );
+        assertEquals("CDC source connector id must not be blank", failure.getMessage());
+    }
+
+    @Test
+    void blankTargetConnectorIdFailsBeforeRegistryMutation() {
+        CdcTargetRegistry registry = new CdcTargetRegistry();
+        CdcTargetConnector blank = target("");
+        IllegalArgumentException failure = assertThrows(IllegalArgumentException.class, () -> registry.register(blank));
+        assertEquals("CDC target connector id must not be blank", failure.getMessage());
+    }
+
+    @Test
+    void sourceConnectorCollectionCannotDeleteRegistrationAuthority() {
+        CdcSourceRegistry registry = new CdcSourceRegistry(List.of(source("immutable-source")));
+        assertThrows(UnsupportedOperationException.class, () -> registry.all().clear());
+        assertTrue(registry.find("immutable-source").isPresent());
+    }
+
+    @Test
+    void targetConnectorCollectionCannotDeleteRegistrationAuthority() {
+        CdcTargetRegistry registry = new CdcTargetRegistry();
+        assertThrows(UnsupportedOperationException.class, () -> registry.all().clear());
+        assertTrue(registry.find(KafkaCdcTargetConnector.ID).isPresent());
+        assertTrue(registry.find(JdbcReplicaCdcTargetConnector.ID).isPresent());
+    }
+
+    private static CdcSourceConnector source(String id) {
+        CdcSourceConnector connector = mock(CdcSourceConnector.class);
+        when(connector.id()).thenReturn(id);
+        return connector;
+    }
+
+    private static CdcTargetConnector target(String id) {
+        CdcTargetConnector connector = mock(CdcTargetConnector.class);
+        when(connector.id()).thenReturn(id);
+        return connector;
+    }
+}