fix: make unified database migrations converge

finance/src/test/java/com/baiyue/finance/FinanceWalletContractTest.java

@@ -9,6 +9,21 @@ import java.nio.file.Path;
 import static org.assertj.core.api.Assertions.assertThat;
 
 class FinanceWalletContractTest {
+    @Test
+    void unifiedMigrationDropsTheLegacyBalanceConstraintBeforeRewritingBalances() throws Exception {
+        Path migration = Path.of("deploy/sql/头程数据库统一增量-MySQL8.sql");
+        if (!Files.exists(migration)) migration = Path.of("..").resolve(migration);
+        String sql = Files.readString(migration, StandardCharsets.UTF_8);
+        int procedure = sql.indexOf("CREATE PROCEDURE migrate_fin_wallet_credit()");
+        int dropConstraint = sql.indexOf("ALTER TABLE fin_wallet_account DROP CHECK chk_fin_wallet_account_balance", procedure);
+        int rewriteBalance = sql.indexOf("SET actual_balance=actual_balance-credit_used", procedure);
+
+        assertThat(procedure).isGreaterThanOrEqualTo(0);
+        assertThat(sql.substring(procedure, rewriteBalance))
+            .contains("CHECK_CLAUSE LIKE '%actual_balance%'", "v_legacy_wallet_constraint OR v_credit_expiry_missing");
+        assertThat(dropConstraint).isBetween(procedure, rewriteBalance - 1);
+    }
+
     @Test
     void schemaKeepsBalancesConsistentAndRechargeReviewTraceable() throws Exception {
         String sql = Files.readString(Path.of("src/main/resources/db/finance.sql"), StandardCharsets.UTF_8);