Code format for test cases (#31076)

diff --git a/features/encrypt/core/src/test/java/org/apache/shardingsphere/encrypt/yaml/swapper/EncryptRuleConfigurationRepositoryTupleSwapperTest.java b/features/encrypt/core/src/test/java/org/apache/shardingsphere/encrypt/yaml/swapper/EncryptRuleConfigurationRepositoryTupleSwapperTest.java
index 995e762..fe0fca2 100644
--- a/features/encrypt/core/src/test/java/org/apache/shardingsphere/encrypt/yaml/swapper/EncryptRuleConfigurationRepositoryTupleSwapperTest.java
+++ b/features/encrypt/core/src/test/java/org/apache/shardingsphere/encrypt/yaml/swapper/EncryptRuleConfigurationRepositoryTupleSwapperTest.java
@@ -81,11 +81,10 @@
         Optional<YamlEncryptRuleConfiguration> actual = swapper.swapToObject0(repositoryTuples);
         assertTrue(actual.isPresent());
         assertThat(actual.get().getTables().size(), is(1));
-        assertThat(actual.get().getTables().values().iterator().next().getName(), is("foo"));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().size(), is(1));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().values().iterator().next().getName(), is("foo_column"));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().values().iterator().next().getCipher().getName(), is("FIXTURE"));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().values().iterator().next().getCipher().getEncryptorName(), is("FOO"));
+        assertThat(actual.get().getTables().get("foo").getColumns().size(), is(1));
+        assertThat(actual.get().getTables().get("foo").getColumns().get("foo_column").getName(), is("foo_column"));
+        assertThat(actual.get().getTables().get("foo").getColumns().get("foo_column").getCipher().getName(), is("FIXTURE"));
+        assertThat(actual.get().getTables().get("foo").getColumns().get("foo_column").getCipher().getEncryptorName(), is("FOO"));
         assertThat(actual.get().getEncryptors().size(), is(1));
         assertThat(actual.get().getEncryptors().get("FOO").getType(), is("FOO"));
         assertTrue(actual.get().getEncryptors().get("FOO").getProps().isEmpty());
diff --git a/features/mask/core/src/test/java/org/apache/shardingsphere/mask/yaml/swapper/MaskRuleConfigurationRepositoryTupleSwapperTest.java b/features/mask/core/src/test/java/org/apache/shardingsphere/mask/yaml/swapper/MaskRuleConfigurationRepositoryTupleSwapperTest.java
index 810af7f..2e02bb5 100644
--- a/features/mask/core/src/test/java/org/apache/shardingsphere/mask/yaml/swapper/MaskRuleConfigurationRepositoryTupleSwapperTest.java
+++ b/features/mask/core/src/test/java/org/apache/shardingsphere/mask/yaml/swapper/MaskRuleConfigurationRepositoryTupleSwapperTest.java
@@ -78,10 +78,9 @@
         Optional<YamlMaskRuleConfiguration> actual = new MaskRuleConfigurationRepositoryTupleSwapper().swapToObject0(repositoryTuples);
         assertTrue(actual.isPresent());
         assertThat(actual.get().getTables().size(), is(1));
-        assertThat(actual.get().getTables().values().iterator().next().getName(), is("foo"));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().size(), is(1));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().values().iterator().next().getLogicColumn(), is("foo_column"));
-        assertThat(actual.get().getTables().values().iterator().next().getColumns().values().iterator().next().getMaskAlgorithm(), is("FIXTURE"));
+        assertThat(actual.get().getTables().get("foo").getColumns().size(), is(1));
+        assertThat(actual.get().getTables().get("foo").getColumns().get("foo_column").getLogicColumn(), is("foo_column"));
+        assertThat(actual.get().getTables().get("foo").getColumns().get("foo_column").getMaskAlgorithm(), is("FIXTURE"));
         assertThat(actual.get().getMaskAlgorithms().size(), is(1));
         assertThat(actual.get().getMaskAlgorithms().get("FIXTURE").getType(), is("FIXTURE"));
         assertTrue(actual.get().getMaskAlgorithms().get("FIXTURE").getProps().isEmpty());
diff --git a/features/mask/distsql/handler/src/test/java/org/apache/shardingsphere/mask/distsql/handler/converter/MaskRuleStatementConverterTest.java b/features/mask/distsql/handler/src/test/java/org/apache/shardingsphere/mask/distsql/handler/converter/MaskRuleStatementConverterTest.java
index 2be3381..54a5fce 100644
--- a/features/mask/distsql/handler/src/test/java/org/apache/shardingsphere/mask/distsql/handler/converter/MaskRuleStatementConverterTest.java
+++ b/features/mask/distsql/handler/src/test/java/org/apache/shardingsphere/mask/distsql/handler/converter/MaskRuleStatementConverterTest.java
@@ -40,8 +40,7 @@
         assertThat(actual.getTables().iterator().next().getName(), is("t_mask"));
         assertThat(actual.getTables().iterator().next().getColumns().iterator().next().getLogicColumn(), is("user_id"));
         assertThat(actual.getTables().iterator().next().getColumns().iterator().next().getMaskAlgorithm(), is("t_mask_user_id_md5"));
-        assertThat(actual.getMaskAlgorithms().keySet().iterator().next(), is("t_mask_user_id_md5"));
-        assertTrue(actual.getMaskAlgorithms().values().iterator().next().getType().contains("MD5"));
+        assertTrue(actual.getMaskAlgorithms().get("t_mask_user_id_md5").getType().contains("MD5"));
     }
     
     private Collection<MaskColumnSegment> createColumns() {
diff --git a/features/readwrite-splitting/core/src/test/java/org/apache/shardingsphere/readwritesplitting/yaml/swapper/ReadwriteSplittingRuleConfigurationRepositoryTupleSwapperTest.java b/features/readwrite-splitting/core/src/test/java/org/apache/shardingsphere/readwritesplitting/yaml/swapper/ReadwriteSplittingRuleConfigurationRepositoryTupleSwapperTest.java
index 0cc59a7..b8356c2 100644
--- a/features/readwrite-splitting/core/src/test/java/org/apache/shardingsphere/readwritesplitting/yaml/swapper/ReadwriteSplittingRuleConfigurationRepositoryTupleSwapperTest.java
+++ b/features/readwrite-splitting/core/src/test/java/org/apache/shardingsphere/readwritesplitting/yaml/swapper/ReadwriteSplittingRuleConfigurationRepositoryTupleSwapperTest.java
@@ -81,11 +81,10 @@
         Optional<YamlReadwriteSplittingRuleConfiguration> actual = swapper.swapToObject0(repositoryTuples);
         assertTrue(actual.isPresent());
         assertThat(actual.get().getDataSourceGroups().size(), is(1));
-        assertThat(actual.get().getDataSourceGroups().keySet().iterator().next(), is("foo_group"));
-        assertThat(actual.get().getDataSourceGroups().values().iterator().next().getWriteDataSourceName(), is("write_ds"));
-        assertThat(actual.get().getDataSourceGroups().values().iterator().next().getReadDataSourceNames().size(), is(2));
-        assertThat(actual.get().getDataSourceGroups().values().iterator().next().getLoadBalancerName(), is("random"));
-        assertThat(actual.get().getDataSourceGroups().values().iterator().next().getTransactionalReadQueryStrategy(), is(TransactionalReadQueryStrategy.DYNAMIC.name()));
+        assertThat(actual.get().getDataSourceGroups().get("foo_group").getWriteDataSourceName(), is("write_ds"));
+        assertThat(actual.get().getDataSourceGroups().get("foo_group").getReadDataSourceNames().size(), is(2));
+        assertThat(actual.get().getDataSourceGroups().get("foo_group").getLoadBalancerName(), is("random"));
+        assertThat(actual.get().getDataSourceGroups().get("foo_group").getTransactionalReadQueryStrategy(), is(TransactionalReadQueryStrategy.DYNAMIC.name()));
         assertThat(actual.get().getLoadBalancers().size(), is(1));
         assertThat(actual.get().getLoadBalancers().get("random").getType(), is("random"));
         assertTrue(actual.get().getLoadBalancers().get("random").getProps().isEmpty());
diff --git a/features/readwrite-splitting/distsql/handler/src/test/java/org/apache/shardingsphere/readwritesplitting/distsql/handler/converter/ReadwriteSplittingRuleStatementConverterTest.java b/features/readwrite-splitting/distsql/handler/src/test/java/org/apache/shardingsphere/readwritesplitting/distsql/handler/converter/ReadwriteSplittingRuleStatementConverterTest.java
index 2b4f6d9..7d733c6 100644
--- a/features/readwrite-splitting/distsql/handler/src/test/java/org/apache/shardingsphere/readwritesplitting/distsql/handler/converter/ReadwriteSplittingRuleStatementConverterTest.java
+++ b/features/readwrite-splitting/distsql/handler/src/test/java/org/apache/shardingsphere/readwritesplitting/distsql/handler/converter/ReadwriteSplittingRuleStatementConverterTest.java
@@ -61,9 +61,7 @@
         assertThat(actualRuleConfig.getLoadBalancerName(), is(expectedLoadBalancerName));
         assertThat(actualRuleConfig.getWriteDataSourceName(), is(expectedSingleReadwriteSplittingRuleSegment.getWriteDataSource()));
         assertThat(actualRuleConfig.getReadDataSourceNames(), is(expectedSingleReadwriteSplittingRuleSegment.getReadDataSources()));
-        String actualLoadBalancerName = actualSingleRuleSegmentConvertResultLoadBalancers.keySet().iterator().next();
-        assertThat(actualLoadBalancerName, is(expectedLoadBalancerName));
-        AlgorithmConfiguration actualSphereAlgorithmConfig = actualSingleRuleSegmentConvertResultLoadBalancers.get(actualLoadBalancerName);
+        AlgorithmConfiguration actualSphereAlgorithmConfig = actualSingleRuleSegmentConvertResultLoadBalancers.get(expectedLoadBalancerName);
         assertThat(actualSphereAlgorithmConfig.getType(), is(expectedSingleReadwriteSplittingRuleSegment.getLoadBalancer().getName()));
         assertThat(actualSphereAlgorithmConfig.getProps(), is(expectedSingleReadwriteSplittingRuleSegment.getLoadBalancer().getProps()));
     }
diff --git a/features/shadow/core/src/test/java/org/apache/shardingsphere/shadow/yaml/swapper/ShadowRuleConfigurationRepositoryTupleSwapperTest.java b/features/shadow/core/src/test/java/org/apache/shardingsphere/shadow/yaml/swapper/ShadowRuleConfigurationRepositoryTupleSwapperTest.java
index 0be89d1..0791999 100644
--- a/features/shadow/core/src/test/java/org/apache/shardingsphere/shadow/yaml/swapper/ShadowRuleConfigurationRepositoryTupleSwapperTest.java
+++ b/features/shadow/core/src/test/java/org/apache/shardingsphere/shadow/yaml/swapper/ShadowRuleConfigurationRepositoryTupleSwapperTest.java
@@ -95,9 +95,8 @@
         Optional<YamlShadowRuleConfiguration> actual = swapper.swapToObject0(repositoryTuples);
         assertTrue(actual.isPresent());
         assertThat(actual.get().getDataSources().size(), is(1));
-        assertThat(actual.get().getDataSources().keySet().iterator().next(), is("foo_db"));
-        assertThat(actual.get().getDataSources().values().iterator().next().getProductionDataSourceName(), is("ds_0"));
-        assertThat(actual.get().getDataSources().values().iterator().next().getShadowDataSourceName(), is("ds_1"));
+        assertThat(actual.get().getDataSources().get("foo_db").getProductionDataSourceName(), is("ds_0"));
+        assertThat(actual.get().getDataSources().get("foo_db").getShadowDataSourceName(), is("ds_1"));
         assertThat(actual.get().getTables().size(), is(1));
         assertThat(actual.get().getTables().get("foo_table").getDataSourceNames().size(), is(1));
         assertThat(actual.get().getTables().get("foo_table").getDataSourceNames().iterator().next(), is("ds_0"));