Add test cases on DefaultDataSourceChangedProcessor

kernel/single/core/src/test/java/org/apache/shardingsphere/single/rule/changed/DefaultDataSourceChangedProcessorTest.java

@@ -0,0 +1,79 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.shardingsphere.single.rule.changed;
+
+import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
+import org.apache.shardingsphere.infra.metadata.database.rule.RuleMetaData;
+import org.apache.shardingsphere.infra.spi.type.typed.TypedSPILoader;
+import org.apache.shardingsphere.mode.event.dispatch.rule.alter.AlterRuleItemEvent;
+import org.apache.shardingsphere.mode.event.dispatch.rule.drop.DropRuleItemEvent;
+import org.apache.shardingsphere.mode.spi.RuleItemConfigurationChangedProcessor;
+import org.apache.shardingsphere.single.config.SingleRuleConfiguration;
+import org.apache.shardingsphere.single.rule.SingleRule;
+import org.junit.jupiter.api.Test;
+
+import java.util.Collections;
+import java.util.Optional;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+class DefaultDataSourceChangedProcessorTest {
+
+    @SuppressWarnings("unchecked")
+    private final RuleItemConfigurationChangedProcessor<SingleRuleConfiguration, String> processor = TypedSPILoader.getService(
+            RuleItemConfigurationChangedProcessor.class, "single.default_data_source");
+
+    @Test
+    void assertSwapRuleItemConfiguration() {
+        String actual = processor.swapRuleItemConfiguration(mock(AlterRuleItemEvent.class), "foo_ds");
+        assertThat(actual, is("foo_ds"));
+    }
+
+    @Test
+    void assertFindRuleConfiguration() {
+        SingleRuleConfiguration ruleConfig = mock(SingleRuleConfiguration.class);
+        assertThat(processor.findRuleConfiguration(mockDatabase(ruleConfig)), is(ruleConfig));
+    }
+
+    private ShardingSphereDatabase mockDatabase(final SingleRuleConfiguration ruleConfig) {
+        SingleRule rule = mock(SingleRule.class);
+        when(rule.getConfiguration()).thenReturn(ruleConfig);
+        ShardingSphereDatabase result = mock(ShardingSphereDatabase.class);
+        when(result.getRuleMetaData()).thenReturn(new RuleMetaData(Collections.singleton(rule)));
+        return result;
+    }
+
+    @Test
+    void assertChangeRuleItemConfiguration() {
+        SingleRuleConfiguration currentRuleConfig = new SingleRuleConfiguration(Collections.emptyList(), "foo_ds");
+        String toBeChangedItemConfig = "bar_ds";
+        processor.changeRuleItemConfiguration(mock(AlterRuleItemEvent.class), currentRuleConfig, toBeChangedItemConfig);
+        assertThat(currentRuleConfig.getDefaultDataSource(), is(Optional.of("bar_ds")));
+    }
+
+    @Test
+    void assertDropRuleItemConfiguration() {
+        SingleRuleConfiguration currentRuleConfig = new SingleRuleConfiguration(Collections.emptyList(), "foo_ds");
+        processor.dropRuleItemConfiguration(mock(DropRuleItemEvent.class), currentRuleConfig);
+        assertFalse(currentRuleConfig.getDefaultDataSource().isPresent());
+    }
+}