X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/lucene-java-3.5.0/lucene/src/test/org/apache/lucene/util/TestNumericUtils.java

diff --git a/lucene-java-3.5.0/lucene/src/test/org/apache/lucene/util/TestNumericUtils.java b/lucene-java-3.5.0/lucene/src/test/org/apache/lucene/util/TestNumericUtils.java
new file mode 100644
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--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/test/org/apache/lucene/util/TestNumericUtils.java
@@ -0,0 +1,558 @@
+package org.apache.lucene.util;
+
+/**
+* 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.
+*/
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.Random;
+
+public class TestNumericUtils extends LuceneTestCase {
+
+  public void testLongConversionAndOrdering() throws Exception {
+    // generate a series of encoded longs, each numerical one bigger than the one before
+    String last=null;
+    for (long l=-100000L; l<100000L; l++) {
+      String act=NumericUtils.longToPrefixCoded(l);
+      if (last!=null) {
+        // test if smaller
+        assertTrue("actual bigger than last", last.compareTo(act) < 0 );
+      }
+      // test is back and forward conversion works
+      assertEquals("forward and back conversion should generate same long", l, NumericUtils.prefixCodedToLong(act));
+      // next step
+      last=act;
+    }
+  }
+
+  public void testIntConversionAndOrdering() throws Exception {
+    // generate a series of encoded ints, each numerical one bigger than the one before
+    String last=null;
+    for (int i=-100000; i<100000; i++) {
+      String act=NumericUtils.intToPrefixCoded(i);
+      if (last!=null) {
+        // test if smaller
+        assertTrue("actual bigger than last", last.compareTo(act) < 0 );
+      }
+      // test is back and forward conversion works
+      assertEquals("forward and back conversion should generate same int", i, NumericUtils.prefixCodedToInt(act));
+      // next step
+      last=act;
+    }
+  }
+
+  public void testLongSpecialValues() throws Exception {
+    long[] vals=new long[]{
+      Long.MIN_VALUE, Long.MIN_VALUE+1, Long.MIN_VALUE+2, -5003400000000L,
+      -4000L, -3000L, -2000L, -1000L, -1L, 0L, 1L, 10L, 300L, 50006789999999999L, Long.MAX_VALUE-2, Long.MAX_VALUE-1, Long.MAX_VALUE
+    };
+    String[] prefixVals=new String[vals.length];
+    
+    for (int i=0; i<vals.length; i++) {
+      prefixVals[i]=NumericUtils.longToPrefixCoded(vals[i]);
+      
+      // check forward and back conversion
+      assertEquals( "forward and back conversion should generate same long", vals[i], NumericUtils.prefixCodedToLong(prefixVals[i]) );
+
+      // test if decoding values as int fails correctly
+      try {
+        NumericUtils.prefixCodedToInt(prefixVals[i]);
+        fail("decoding a prefix coded long value as int should fail");
+      } catch (NumberFormatException e) {
+        // worked
+      }
+    }
+    
+    // check sort order (prefixVals should be ascending)
+    for (int i=1; i<prefixVals.length; i++) {
+      assertTrue( "check sort order", prefixVals[i-1].compareTo( prefixVals[i] ) < 0 );
+    }
+        
+    // check the prefix encoding, lower precision should have the difference to original value equal to the lower removed bits
+    for (int i=0; i<vals.length; i++) {
+      for (int j=0; j<64; j++) {
+        long prefixVal=NumericUtils.prefixCodedToLong(NumericUtils.longToPrefixCoded(vals[i], j));
+        long mask=(1L << j) - 1L;
+        assertEquals( "difference between prefix val and original value for "+vals[i]+" with shift="+j, vals[i] & mask, vals[i]-prefixVal );
+      }
+    }
+  }
+
+  public void testIntSpecialValues() throws Exception {
+    int[] vals=new int[]{
+      Integer.MIN_VALUE, Integer.MIN_VALUE+1, Integer.MIN_VALUE+2, -64765767,
+      -4000, -3000, -2000, -1000, -1, 0, 1, 10, 300, 765878989, Integer.MAX_VALUE-2, Integer.MAX_VALUE-1, Integer.MAX_VALUE
+    };
+    String[] prefixVals=new String[vals.length];
+    
+    for (int i=0; i<vals.length; i++) {
+      prefixVals[i]=NumericUtils.intToPrefixCoded(vals[i]);
+      
+      // check forward and back conversion
+      assertEquals( "forward and back conversion should generate same int", vals[i], NumericUtils.prefixCodedToInt(prefixVals[i]) );
+      
+      // test if decoding values as long fails correctly
+      try {
+        NumericUtils.prefixCodedToLong(prefixVals[i]);
+        fail("decoding a prefix coded int value as long should fail");
+      } catch (NumberFormatException e) {
+        // worked
+      }
+    }
+    
+    // check sort order (prefixVals should be ascending)
+    for (int i=1; i<prefixVals.length; i++) {
+      assertTrue( "check sort order", prefixVals[i-1].compareTo( prefixVals[i] ) < 0 );
+    }
+    
+    // check the prefix encoding, lower precision should have the difference to original value equal to the lower removed bits
+    for (int i=0; i<vals.length; i++) {
+      for (int j=0; j<32; j++) {
+        int prefixVal=NumericUtils.prefixCodedToInt(NumericUtils.intToPrefixCoded(vals[i], j));
+        int mask=(1 << j) - 1;
+        assertEquals( "difference between prefix val and original value for "+vals[i]+" with shift="+j, vals[i] & mask, vals[i]-prefixVal );
+      }
+    }
+  }
+
+  public void testDoubles() throws Exception {
+    double[] vals=new double[]{
+      Double.NEGATIVE_INFINITY, -2.3E25, -1.0E15, -1.0, -1.0E-1, -1.0E-2, -0.0, 
+      +0.0, 1.0E-2, 1.0E-1, 1.0, 1.0E15, 2.3E25, Double.POSITIVE_INFINITY, Double.NaN
+    };
+    long[] longVals=new long[vals.length];
+    
+    // check forward and back conversion
+    for (int i=0; i<vals.length; i++) {
+      longVals[i]=NumericUtils.doubleToSortableLong(vals[i]);
+      assertTrue( "forward and back conversion should generate same double", Double.compare(vals[i], NumericUtils.sortableLongToDouble(longVals[i]))==0 );
+    }
+    
+    // check sort order (prefixVals should be ascending)
+    for (int i=1; i<longVals.length; i++) {
+      assertTrue( "check sort order", longVals[i-1] < longVals[i] );
+    }
+  }
+
+  public static final double[] DOUBLE_NANs = {
+    Double.NaN,
+    Double.longBitsToDouble(0x7ff0000000000001L),
+    Double.longBitsToDouble(0x7fffffffffffffffL),
+    Double.longBitsToDouble(0xfff0000000000001L),
+    Double.longBitsToDouble(0xffffffffffffffffL)
+  };
+
+  public void testSortableDoubleNaN() {
+    final long plusInf = NumericUtils.doubleToSortableLong(Double.POSITIVE_INFINITY);
+    for (double nan : DOUBLE_NANs) {
+      assertTrue(Double.isNaN(nan));
+      final long sortable = NumericUtils.doubleToSortableLong(nan);
+      assertTrue("Double not sorted correctly: " + nan + ", long repr: " 
+          + sortable + ", positive inf.: " + plusInf, sortable > plusInf);
+    }
+  }
+  
+  public void testFloats() throws Exception {
+    float[] vals=new float[]{
+      Float.NEGATIVE_INFINITY, -2.3E25f, -1.0E15f, -1.0f, -1.0E-1f, -1.0E-2f, -0.0f, 
+      +0.0f, 1.0E-2f, 1.0E-1f, 1.0f, 1.0E15f, 2.3E25f, Float.POSITIVE_INFINITY, Float.NaN
+    };
+    int[] intVals=new int[vals.length];
+    
+    // check forward and back conversion
+    for (int i=0; i<vals.length; i++) {
+      intVals[i]=NumericUtils.floatToSortableInt(vals[i]);
+      assertTrue( "forward and back conversion should generate same double", Float.compare(vals[i], NumericUtils.sortableIntToFloat(intVals[i]))==0 );
+    }
+    
+    // check sort order (prefixVals should be ascending)
+    for (int i=1; i<intVals.length; i++) {
+      assertTrue( "check sort order", intVals[i-1] < intVals[i] );
+    }
+  }
+
+  public static final float[] FLOAT_NANs = {
+    Float.NaN,
+    Float.intBitsToFloat(0x7f800001),
+    Float.intBitsToFloat(0x7fffffff),
+    Float.intBitsToFloat(0xff800001),
+    Float.intBitsToFloat(0xffffffff)
+  };
+
+  public void testSortableFloatNaN() {
+    final int plusInf = NumericUtils.floatToSortableInt(Float.POSITIVE_INFINITY);
+    for (float nan : FLOAT_NANs) {
+      assertTrue(Float.isNaN(nan));
+      final int sortable = NumericUtils.floatToSortableInt(nan);
+      assertTrue("Float not sorted correctly: " + nan + ", int repr: " 
+          + sortable + ", positive inf.: " + plusInf, sortable > plusInf);
+    }
+  }
+
+  // INFO: Tests for trieCodeLong()/trieCodeInt() not needed because implicitely tested by range filter tests
+  
+  /** Note: The neededBounds Iterable must be unsigned (easier understanding what's happening) */
+  private void assertLongRangeSplit(final long lower, final long upper, int precisionStep,
+    final boolean useBitSet, final Iterable<Long> expectedBounds, final Iterable<Integer> expectedShifts
+  ) throws Exception {
+    // Cannot use FixedBitSet since the range could be long:
+    final OpenBitSet bits=useBitSet ? new OpenBitSet(upper-lower+1) : null;
+    final Iterator<Long> neededBounds = (expectedBounds == null) ? null : expectedBounds.iterator();
+    final Iterator<Integer> neededShifts = (expectedShifts == null) ? null : expectedShifts.iterator();
+
+    NumericUtils.splitLongRange(new NumericUtils.LongRangeBuilder() {
+      @Override
+      public void addRange(long min, long max, int shift) {
+        assertTrue("min, max should be inside bounds", min>=lower && min<=upper && max>=lower && max<=upper);
+        if (useBitSet) for (long l=min; l<=max; l++) {
+          assertFalse("ranges should not overlap", bits.getAndSet(l-lower) );
+          // extra exit condition to prevent overflow on MAX_VALUE
+          if (l == max) break;
+        }
+        if (neededBounds == null || neededShifts == null)
+          return;
+        // make unsigned longs for easier display and understanding
+        min ^= 0x8000000000000000L;
+        max ^= 0x8000000000000000L;
+        //System.out.println("0x"+Long.toHexString(min>>>shift)+"L,0x"+Long.toHexString(max>>>shift)+"L)/*shift="+shift+"*/,");
+        assertEquals( "shift", neededShifts.next().intValue(), shift);
+        assertEquals( "inner min bound", neededBounds.next().longValue(), min>>>shift);
+        assertEquals( "inner max bound", neededBounds.next().longValue(), max>>>shift);
+      }
+    }, precisionStep, lower, upper);
+    
+    if (useBitSet) {
+      // after flipping all bits in the range, the cardinality should be zero
+      bits.flip(0,upper-lower+1);
+      assertEquals("The sub-range concenated should match the whole range", 0, bits.cardinality());
+    }
+  }
+  
+  /** LUCENE-2541: NumericRangeQuery errors with endpoints near long min and max values */
+  public void testLongExtremeValues() throws Exception {
+    // upper end extremes
+    assertLongRangeSplit(Long.MAX_VALUE, Long.MAX_VALUE, 1, true, Arrays.asList(
+      0xffffffffffffffffL,0xffffffffffffffffL
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MAX_VALUE, Long.MAX_VALUE, 2, true, Arrays.asList(
+      0xffffffffffffffffL,0xffffffffffffffffL
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MAX_VALUE, Long.MAX_VALUE, 4, true, Arrays.asList(
+      0xffffffffffffffffL,0xffffffffffffffffL
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MAX_VALUE, Long.MAX_VALUE, 6, true, Arrays.asList(
+      0xffffffffffffffffL,0xffffffffffffffffL
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MAX_VALUE, Long.MAX_VALUE, 8, true, Arrays.asList(
+      0xffffffffffffffffL,0xffffffffffffffffL
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MAX_VALUE, Long.MAX_VALUE, 64, true, Arrays.asList(
+      0xffffffffffffffffL,0xffffffffffffffffL
+    ), Arrays.asList(
+      0
+    ));
+
+    assertLongRangeSplit(Long.MAX_VALUE-0xfL, Long.MAX_VALUE, 4, true, Arrays.asList(
+      0xfffffffffffffffL,0xfffffffffffffffL
+    ), Arrays.asList(
+      4
+    ));
+    assertLongRangeSplit(Long.MAX_VALUE-0x10L, Long.MAX_VALUE, 4, true, Arrays.asList(
+      0xffffffffffffffefL,0xffffffffffffffefL,
+      0xfffffffffffffffL,0xfffffffffffffffL
+    ), Arrays.asList(
+      0, 4
+    ));
+
+    // lower end extremes
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE, 1, true, Arrays.asList(
+      0x0000000000000000L,0x0000000000000000L
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE, 2, true, Arrays.asList(
+      0x0000000000000000L,0x0000000000000000L
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE, 4, true, Arrays.asList(
+      0x0000000000000000L,0x0000000000000000L
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE, 6, true, Arrays.asList(
+      0x0000000000000000L,0x0000000000000000L
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE, 8, true, Arrays.asList(
+      0x0000000000000000L,0x0000000000000000L
+    ), Arrays.asList(
+      0
+    ));
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE, 64, true, Arrays.asList(
+      0x0000000000000000L,0x0000000000000000L
+    ), Arrays.asList(
+      0
+    ));
+
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE+0xfL, 4, true, Arrays.asList(
+      0x000000000000000L,0x000000000000000L
+    ), Arrays.asList(
+      4
+    ));
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MIN_VALUE+0x10L, 4, true, Arrays.asList(
+      0x0000000000000010L,0x0000000000000010L,
+      0x000000000000000L,0x000000000000000L
+    ), Arrays.asList(
+      0, 4
+    ));
+  }
+  
+  public void testRandomSplit() throws Exception {
+    long num = (long) atLeast(10);
+    for (long i=0; i < num; i++) {
+      executeOneRandomSplit(random);
+    }
+  }
+  
+  private void executeOneRandomSplit(final Random random) throws Exception {
+    long lower = randomLong(random);
+    long len = random.nextInt(16384*1024); // not too large bitsets, else OOME!
+    while (lower + len < lower) { // overflow
+      lower >>= 1;
+    }
+    assertLongRangeSplit(lower, lower + len, random.nextInt(64) + 1, true, null, null);
+  }
+  
+  private long randomLong(final Random random) {
+    long val;
+    switch(random.nextInt(4)) {
+      case 0:
+        val = 1L << (random.nextInt(63)); //  patterns like 0x000000100000 (-1 yields patterns like 0x0000fff)
+        break;
+      case 1:
+        val = -1L << (random.nextInt(63)); // patterns like 0xfffff00000
+        break;
+      default:
+        val = random.nextLong();
+    }
+
+    val += random.nextInt(5)-2;
+
+    if (random.nextBoolean()) {
+      if (random.nextBoolean()) val += random.nextInt(100)-50;
+      if (random.nextBoolean()) val = ~val;
+      if (random.nextBoolean()) val = val<<1;
+      if (random.nextBoolean()) val = val>>>1;
+    }
+
+    return val;
+  }
+  
+  public void testSplitLongRange() throws Exception {
+    // a hard-coded "standard" range
+    assertLongRangeSplit(-5000L, 9500L, 4, true, Arrays.asList(
+      0x7fffffffffffec78L,0x7fffffffffffec7fL,
+      0x8000000000002510L,0x800000000000251cL,
+      0x7fffffffffffec8L, 0x7fffffffffffecfL,
+      0x800000000000250L, 0x800000000000250L,
+      0x7fffffffffffedL,  0x7fffffffffffefL,
+      0x80000000000020L,  0x80000000000024L,
+      0x7ffffffffffffL,   0x8000000000001L
+    ), Arrays.asList(
+      0, 0,
+      4, 4,
+      8, 8,
+      12
+    ));
+    
+    // the same with no range splitting
+    assertLongRangeSplit(-5000L, 9500L, 64, true, Arrays.asList(
+      0x7fffffffffffec78L,0x800000000000251cL
+    ), Arrays.asList(
+      0
+    ));
+    
+    // this tests optimized range splitting, if one of the inner bounds
+    // is also the bound of the next lower precision, it should be used completely
+    assertLongRangeSplit(0L, 1024L+63L, 4, true, Arrays.asList(
+      0x800000000000040L, 0x800000000000043L,
+      0x80000000000000L,  0x80000000000003L
+    ), Arrays.asList(
+      4, 8
+    ));
+    
+    // the full long range should only consist of a lowest precision range; no bitset testing here, as too much memory needed :-)
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MAX_VALUE, 8, false, Arrays.asList(
+      0x00L,0xffL
+    ), Arrays.asList(
+      56
+    ));
+
+    // the same with precisionStep=4
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MAX_VALUE, 4, false, Arrays.asList(
+      0x0L,0xfL
+    ), Arrays.asList(
+      60
+    ));
+
+    // the same with precisionStep=2
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MAX_VALUE, 2, false, Arrays.asList(
+      0x0L,0x3L
+    ), Arrays.asList(
+      62
+    ));
+
+    // the same with precisionStep=1
+    assertLongRangeSplit(Long.MIN_VALUE, Long.MAX_VALUE, 1, false, Arrays.asList(
+      0x0L,0x1L
+    ), Arrays.asList(
+      63
+    ));
+
+    // a inverse range should produce no sub-ranges
+    assertLongRangeSplit(9500L, -5000L, 4, false, Collections.<Long>emptyList(), Collections.<Integer>emptyList());    
+
+    // a 0-length range should reproduce the range itsself
+    assertLongRangeSplit(9500L, 9500L, 4, false, Arrays.asList(
+      0x800000000000251cL,0x800000000000251cL
+    ), Arrays.asList(
+      0
+    ));
+  }
+
+  /** Note: The neededBounds Iterable must be unsigned (easier understanding what's happening) */
+  private void assertIntRangeSplit(final int lower, final int upper, int precisionStep,
+    final boolean useBitSet, final Iterable<Integer> expectedBounds, final Iterable<Integer> expectedShifts
+  ) throws Exception {
+    final FixedBitSet bits=useBitSet ? new FixedBitSet(upper-lower+1) : null;
+    final Iterator<Integer> neededBounds = (expectedBounds == null) ? null : expectedBounds.iterator();
+    final Iterator<Integer> neededShifts = (expectedShifts == null) ? null : expectedShifts.iterator();
+    
+    NumericUtils.splitIntRange(new NumericUtils.IntRangeBuilder() {
+      @Override
+      public void addRange(int min, int max, int shift) {
+        assertTrue("min, max should be inside bounds", min>=lower && min<=upper && max>=lower && max<=upper);
+        if (useBitSet) for (int i=min; i<=max; i++) {
+          assertFalse("ranges should not overlap", bits.getAndSet(i-lower) );
+          // extra exit condition to prevent overflow on MAX_VALUE
+          if (i == max) break;
+        }
+        if (neededBounds == null)
+          return;
+        // make unsigned ints for easier display and understanding
+        min ^= 0x80000000;
+        max ^= 0x80000000;
+        //System.out.println("0x"+Integer.toHexString(min>>>shift)+",0x"+Integer.toHexString(max>>>shift)+")/*shift="+shift+"*/,");
+        assertEquals( "shift", neededShifts.next().intValue(), shift);
+        assertEquals( "inner min bound", neededBounds.next().intValue(), min>>>shift);
+        assertEquals( "inner max bound", neededBounds.next().intValue(), max>>>shift);
+      }
+    }, precisionStep, lower, upper);
+    
+    if (useBitSet) {
+      // after flipping all bits in the range, the cardinality should be zero
+      bits.flip(0, upper-lower+1);
+      assertEquals("The sub-range concenated should match the whole range", 0, bits.cardinality());
+    }
+  }
+  
+  public void testSplitIntRange() throws Exception {
+    // a hard-coded "standard" range
+    assertIntRangeSplit(-5000, 9500, 4, true, Arrays.asList(
+      0x7fffec78,0x7fffec7f,
+      0x80002510,0x8000251c,
+      0x7fffec8, 0x7fffecf,
+      0x8000250, 0x8000250,
+      0x7fffed,  0x7fffef,
+      0x800020,  0x800024,
+      0x7ffff,   0x80001
+    ), Arrays.asList(
+      0, 0,
+      4, 4,
+      8, 8,
+      12
+    ));
+    
+    // the same with no range splitting
+    assertIntRangeSplit(-5000, 9500, 32, true, Arrays.asList(
+      0x7fffec78,0x8000251c
+    ), Arrays.asList(
+      0
+    ));
+    
+    // this tests optimized range splitting, if one of the inner bounds
+    // is also the bound of the next lower precision, it should be used completely
+    assertIntRangeSplit(0, 1024+63, 4, true, Arrays.asList(
+      0x8000040, 0x8000043,
+      0x800000,  0x800003
+    ), Arrays.asList(
+      4, 8
+    ));
+    
+    // the full int range should only consist of a lowest precision range; no bitset testing here, as too much memory needed :-)
+    assertIntRangeSplit(Integer.MIN_VALUE, Integer.MAX_VALUE, 8, false, Arrays.asList(
+      0x00,0xff
+    ), Arrays.asList(
+      24
+    ));
+
+    // the same with precisionStep=4
+    assertIntRangeSplit(Integer.MIN_VALUE, Integer.MAX_VALUE, 4, false, Arrays.asList(
+      0x0,0xf
+    ), Arrays.asList(
+      28
+    ));
+
+    // the same with precisionStep=2
+    assertIntRangeSplit(Integer.MIN_VALUE, Integer.MAX_VALUE, 2, false, Arrays.asList(
+      0x0,0x3
+    ), Arrays.asList(
+      30
+    ));
+
+    // the same with precisionStep=1
+    assertIntRangeSplit(Integer.MIN_VALUE, Integer.MAX_VALUE, 1, false, Arrays.asList(
+      0x0,0x1
+    ), Arrays.asList(
+      31
+    ));
+
+    // a inverse range should produce no sub-ranges
+    assertIntRangeSplit(9500, -5000, 4, false, Collections.<Integer>emptyList(), Collections.<Integer>emptyList());    
+
+    // a 0-length range should reproduce the range itsself
+    assertIntRangeSplit(9500, 9500, 4, false, Arrays.asList(
+      0x8000251c,0x8000251c
+    ), Arrays.asList(
+      0
+    ));
+  }
+
+}