add unit tests for shard range split

Change-Id: I75b33c8cff9c7e48fc8f44e9e175f9365a143ee3

hugegraph-core/src/main/java/com/baidu/hugegraph/backend/store/BackendTable.java

@@ -204,7 +204,7 @@ protected long maxKey() {
 
         protected abstract long estimateNumKeys(Session session);
 
-        protected static class Range {
+        public static class Range {
 
             private byte[] startKey;
             private byte[] endKey;
@@ -247,7 +247,6 @@ public List<Shard> splitEven(int count) {
                 }
 
                 assert count > 1;
-                assert startChanged != endChanged;
                 byte[] each = align(new BigInteger(1, subtract(end, start))
                                         .divide(BigInteger.valueOf(count))
                                         .toByteArray(),

hugegraph-test/src/main/java/com/baidu/hugegraph/unit/UnitTestSuite.java

@@ -38,6 +38,7 @@
 import com.baidu.hugegraph.unit.core.ExceptionTest;
 import com.baidu.hugegraph.unit.core.LocksTableTest;
 import com.baidu.hugegraph.unit.core.QueryTest;
+import com.baidu.hugegraph.unit.core.RangeTest;
 import com.baidu.hugegraph.unit.core.RolePermissionTest;
 import com.baidu.hugegraph.unit.core.RowLockTest;
 import com.baidu.hugegraph.unit.core.SecurityManagerTest;
@@ -91,6 +92,7 @@
     ConditionTest.class,
     ConditionQueryFlattenTest.class,
     QueryTest.class,
+    RangeTest.class,
     SecurityManagerTest.class,
     RolePermissionTest.class,
     ExceptionTest.class,

hugegraph-test/src/main/java/com/baidu/hugegraph/unit/core/RangeTest.java

@@ -0,0 +1,172 @@
+/*
+ * Copyright 2017 HugeGraph Authors
+ *
+ * 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 com.baidu.hugegraph.unit.core;
+
+import java.util.List;
+
+import org.apache.logging.log4j.util.Strings;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baidu.hugegraph.backend.store.BackendTable.ShardSpliter.Range;
+import com.baidu.hugegraph.backend.store.Shard;
+import com.baidu.hugegraph.testutil.Assert;
+
+public class RangeTest {
+
+    private static final byte[] START = new byte[]{0x0};
+    private static final byte[] END = new byte[]{
+            -1, -1, -1, -1, -1, -1, -1, -1,
+            -1, -1, -1, -1, -1, -1, -1, -1
+    };
+
+    @Before
+    public void setup() {
+        // pass
+    }
+
+    @After
+    public void teardown() {
+        // pass
+    }
+
+    @Test
+    public void testRangeOfOnlyOneRegion() {
+        // The startKey and endKey is "", if it's the only region of table
+        Range range = new Range(START, END);
+
+        List<Shard> shards = range.splitEven(0);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).start());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).end());
+
+        shards = range.splitEven(1);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).start());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).end());
+
+        shards = range.splitEven(3);
+        Assert.assertEquals(3, shards.size());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).start());
+        Assert.assertEquals("VVVVVVVVVVVVVVVVVVVVVQ==", shards.get(0).end());
+        Assert.assertEquals("VVVVVVVVVVVVVVVVVVVVVQ==", shards.get(1).start());
+        Assert.assertEquals("qqqqqqqqqqqqqqqqqqqqqg==", shards.get(1).end());
+        Assert.assertEquals("qqqqqqqqqqqqqqqqqqqqqg==", shards.get(2).start());
+        Assert.assertEquals(Strings.EMPTY, shards.get(2).end());
+
+        for (int i = 4; i < 100; i++) {
+            range.splitEven(i);
+        }
+    }
+
+    @Test
+    public void testRangeOfRegionWithEndKey() {
+        byte[] end = new byte[]{-3, 0x31, 0x30, 0x30, 0x30, 0x77,
+                                0x20, 0x09, 0x38, 0x31, 0x33, 0x32, 0x35};
+        Range range = new Range(START, end);
+
+        List<Shard> shards = range.splitEven(0);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).start());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNQ==", shards.get(0).end());
+
+        shards = range.splitEven(1);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).start());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNQ==", shards.get(0).end());
+
+        shards = range.splitEven(2);
+        Assert.assertEquals(3, shards.size());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).start());
+        Assert.assertEquals("fpiYGBg7kAScGJmZGg==", shards.get(0).end());
+        Assert.assertEquals("fpiYGBg7kAScGJmZGg==", shards.get(1).start());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNA==", shards.get(1).end());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNA==", shards.get(2).start());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNQ==", shards.get(2).end());
+
+        for (int i = 3; i < 100; i++) {
+            range.splitEven(i);
+        }
+    }
+
+    @Test
+    public void testRangeOfRegionWithStartKey() {
+        byte[] start = new byte[]{-3, 0x35, 0x30, 0x30,
+                                  0x30, 0x77, 0x4e, -37,
+                                  0x31, 0x31, 0x30, 0x30,
+                                  0x30, 0x37, 0x36, 0x33};
+        Range range = new Range(start, END);
+
+        List<Shard> shards = range.splitEven(0);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals("/TUwMDB3TtsxMTAwMDc2Mw==", shards.get(0).start());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).end());
+
+        shards = range.splitEven(1);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals("/TUwMDB3TtsxMTAwMDc2Mw==", shards.get(0).start());
+        Assert.assertEquals(Strings.EMPTY, shards.get(0).end());
+
+        shards = range.splitEven(2);
+        Assert.assertEquals(2, shards.size());
+        Assert.assertEquals("/TUwMDB3TtsxMTAwMDc2Mw==", shards.get(0).start());
+        Assert.assertEquals("/pqYGBg7p22YmJgYGBubGQ==", shards.get(0).end());
+        Assert.assertEquals("/pqYGBg7p22YmJgYGBubGQ==", shards.get(1).start());
+        Assert.assertEquals(Strings.EMPTY, shards.get(1).end());
+
+        for (int i = 3; i < 100; i++) {
+            range.splitEven(i);
+        }
+    }
+
+    @Test
+    public void testRangeOfRegionWithStartKeyAndEndKey() {
+        byte[] start = new byte[]{-3, 0x31, 0x30, 0x30, 0x30, 0x77,
+                                  0x20, 0x09, 0x38, 0x31, 0x33, 0x32, 0x35};
+        byte[] end = new byte[]{-3, 0x31, 0x33, 0x35, 0x33, 0x32,
+                                0x37, 0x34, 0x31, 0x35, 0x32};
+
+        Range range = new Range(start, end);
+
+        List<Shard> shards = range.splitEven(0);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNQ==", shards.get(0).start());
+        Assert.assertEquals("/TEzNTMyNzQxNTI=", shards.get(0).end());
+
+        shards = range.splitEven(1);
+        Assert.assertEquals(1, shards.size());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNQ==", shards.get(0).start());
+        Assert.assertEquals("/TEzNTMyNzQxNTI=", shards.get(0).end());
+
+        shards = range.splitEven(2);
+        Assert.assertEquals(3, shards.size());
+        Assert.assertEquals("/TEwMDB3IAk4MTMyNQ==", shards.get(0).start());
+        Assert.assertEquals("/TExsrHUq560szKZGg==", shards.get(0).end());
+        Assert.assertEquals("/TExsrHUq560szKZGg==", shards.get(1).start());
+        Assert.assertEquals("/TEzNTMyNzQxNTH//w==", shards.get(1).end());
+        Assert.assertEquals("/TEzNTMyNzQxNTH//w==", shards.get(2).start());
+        Assert.assertEquals("/TEzNTMyNzQxNTI=", shards.get(2).end());
+
+        for (int i = 3; i < 100; i++) {
+            range.splitEven(i);
+        }
+    }
+}