Use Cleaner to destroy TemporaryDb in tests:

Register the database in the cleaner
to simplify the teardown operation and make it
more reliable.

Author: dmitry-timofeev

exonum-java-binding/core/src/test/java/com/exonum/binding/core/blockchain/BlockchainDataIntegrationTest.java

@@ -42,23 +42,19 @@
 @Disabled("ECR-4169")
 class BlockchainDataIntegrationTest {
 
-  TemporaryDb db;
   Cleaner cleaner;
+  TemporaryDb db;
 
   @BeforeEach
   void setUp() {
-    db = TemporaryDb.newInstance();
     cleaner = new Cleaner();
+    db = TemporaryDb.newInstance();
+    cleaner.add(db::close);
   }
 
   @AfterEach
   void tearDown() throws CloseFailuresException {
-    if (cleaner != null) {
-      cleaner.close();
-    }
-    if (db != null) {
-      db.close();
-    }
+    cleaner.close();
   }
 
   @Test

exonum-java-binding/core/src/test/java/com/exonum/binding/core/storage/database/PrefixedIntegrationTest.java

@@ -38,14 +38,15 @@ class PrefixedIntegrationTest {
   class WithIndex {
     final String namespace = "test-namespace";
     final String entryName = "test-index";
-    TemporaryDb db;
     Cleaner cleaner;
+    TemporaryDb db;
 
     @BeforeEach
     void initializeDatabase(TestInfo info) throws CloseFailuresException {
       // Create the database
-      db = TemporaryDb.newInstance();
       cleaner = new Cleaner(info.getDisplayName());
+      db = TemporaryDb.newInstance();
+      cleaner.add(db::close);
 
       // Initialize the test index
       try (Cleaner initCleaner = new Cleaner()) {
@@ -144,11 +145,7 @@ void baseCleanerInvalidatesIndexesFromPrefixed() throws CloseFailuresException {
 
     @AfterEach
     void dropDatabase() throws CloseFailuresException {
-      try {
-        cleaner.close();
-      } finally {
-        db.close();
-      }
+      cleaner.close();
     }
   }
 }

exonum-java-binding/core/src/test/java/com/exonum/binding/core/storage/database/ReadonlyForkIntegrationTest.java

@@ -32,24 +32,19 @@
 @Disabled("ECR-4167")
 class ReadonlyForkIntegrationTest {
 
-  private TemporaryDb db;
   private Cleaner cleaner;
+  private TemporaryDb db;
 
   @BeforeEach
   void setupDb() {
-    db = TemporaryDb.newInstance();
     cleaner = new Cleaner();
+    db = TemporaryDb.newInstance();
+    cleaner.add(db::close);
   }
 
   @AfterEach
   void tearDown() throws CloseFailuresException {
-    try {
-      if (cleaner != null) {
-        cleaner.close();
-      }
-    } finally {
-      db.close();
-    }
+    cleaner.close();
   }
 
   @Test