Add test extension [ECR-2634]

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

@@ -24,15 +24,20 @@
 import com.exonum.binding.proxy.CloseFailuresException;
 import com.exonum.binding.storage.database.MemoryDb;
 import com.exonum.binding.storage.database.Snapshot;
+import com.exonum.binding.storage.database.View;
 import com.exonum.binding.test.RequiresNativeLibrary;
 import com.exonum.binding.util.LibraryLoader;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 @RequiresNativeLibrary
+@ExtendWith(ViewTestExtension.class)
 class CoreSchemaProxyIntegrationTest {
 
-  static {
-    LibraryLoader.load();
+  @BeforeEach
+  void setUp(MemoryDb db) {
+    assertThat(db).isNotNull();
   }
 
   @Test
@@ -57,15 +62,10 @@ void getAllBlockHashesTest() throws CloseFailuresException {
   }
 
   @Test
-  void getBlockTransactionsTest() throws CloseFailuresException {
-    try (MemoryDb db = MemoryDb.newInstance();
-         Cleaner cleaner = new Cleaner()) {
-      Snapshot view = db.createSnapshot(cleaner);
-
-      CoreSchemaProxy schema = CoreSchemaProxy.newInstance(view);
-      long height = 0L;
-      assertThat(schema.getBlockTransactions(height)).isEmpty();
-    }
+  void getBlockTransactionsTest(View view) {
+    CoreSchemaProxy schema = CoreSchemaProxy.newInstance(view);
+    long height = 0L;
+    assertThat(schema.getBlockTransactions(height)).isEmpty();
   }
 
 }

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

@@ -0,0 +1,150 @@
+/*
+ * Copyright 2018 The Exonum Team
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.exonum.binding.blockchain;
+
+import com.exonum.binding.proxy.Cleaner;
+import com.exonum.binding.storage.database.Fork;
+import com.exonum.binding.storage.database.MemoryDb;
+import com.exonum.binding.storage.database.Snapshot;
+import com.exonum.binding.storage.database.View;
+import com.exonum.binding.util.LibraryLoader;
+import org.junit.jupiter.api.extension.BeforeEachCallback;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
+import org.junit.jupiter.api.extension.ExtensionContext.Store;
+import org.junit.jupiter.api.extension.ExtensionContext.Store.CloseableResource;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolutionException;
+import org.junit.jupiter.api.extension.ParameterResolver;
+
+/**
+ * This extension allows to easily use Views in tests.
+ *
+ * After annotating the test class with <code>@ExtendWith(ViewTestExtension.class)</code> user is
+ * able to write tests like this:
+ *
+ * <pre><code>
+ * @BeforeEach
+ * void setUp(MemoryDb db) {
+ *   // Use db if needed
+ * }
+ *
+ * @Test
+ * void test(View view) {
+ *   // Test logic
+ * }
+ * </code></pre>
+ *
+ * instead of:
+ *
+ * <pre><code>
+ * static {
+ *   LibraryLoader.load();
+ * }
+ *
+ * MemoryDb db;
+ *
+ * @BeforeEach
+ * void setUp() {
+ *   db = MemoryDb.newInstance();
+ *   // Use db if needed
+ * }
+ *
+ * @Test
+ * void test() {
+ *   try (MemoryDb db = MemoryDb.newInstance();
+ *        Cleaner cleaner = new Cleaner()) {
+ *     View view = db.createSnapshot(cleaner);
+ *     // Test logic
+ *   }
+ * }
+ * </code></pre>
+ */
+public class ViewTestExtension implements ParameterResolver, BeforeEachCallback {
+
+  private static final String KEY = "ResourceKey";
+
+  static {
+    LibraryLoader.load();
+  }
+
+  @Override
+  public void beforeEach(ExtensionContext extensionContext) throws Exception {
+    MemoryDb db = MemoryDb.newInstance();
+    Cleaner cleaner = new Cleaner();
+    getStore(extensionContext).put(KEY, new CloseableDbAndCleaner(db, cleaner));
+  }
+
+  @Override
+  public boolean supportsParameter(ParameterContext parameterContext,
+      ExtensionContext extensionContext) throws ParameterResolutionException {
+    return parameterContext.getParameter().getType() == MemoryDb.class
+        || parameterContext.getParameter().getType() == View.class
+        || parameterContext.getParameter().getType() == Snapshot.class
+        || parameterContext.getParameter().getType() == Fork.class;
+  }
+
+  @Override
+  public Object resolveParameter(
+      ParameterContext parameterContext, ExtensionContext extensionContext)
+      throws ParameterResolutionException {
+    CloseableDbAndCleaner resources =
+        getStore(extensionContext).get(KEY, CloseableDbAndCleaner.class);
+    MemoryDb memoryDb = resources.getMemoryDb();
+    if (parameterContext.getParameter().getType() == MemoryDb.class) {
+      return memoryDb;
+    }
+    else {
+      Cleaner cleaner = resources.getCleaner();
+      if (parameterContext.getParameter().getType() == Fork.class) {
+        return memoryDb.createFork(cleaner);
+      } else {
+        return memoryDb.createSnapshot(cleaner);
+      }
+    }
+  }
+
+  private Store getStore(ExtensionContext context) {
+    return context.getStore(Namespace.create(getClass(), context.getRequiredTestMethod()));
+  }
+
+  private static class CloseableDbAndCleaner implements CloseableResource {
+
+    private final MemoryDb memoryDb;
+    private final Cleaner cleaner;
+
+    CloseableDbAndCleaner(MemoryDb memoryDb, Cleaner cleaner) {
+      this.memoryDb = memoryDb;
+      this.cleaner = cleaner;
+    }
+
+    MemoryDb getMemoryDb() {
+      return memoryDb;
+    }
+
+    Cleaner getCleaner() {
+      return cleaner;
+    }
+
+    @Override
+    public void close() throws Throwable {
+      cleaner.close();
+    }
+
+  }
+
+}