Rewrite method to be the same as binaryToHexDigit but working from the end of the array backwards.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/test/java/org/apache/commons/lang3/ConversionTest.java b/src/test/java/org/apache/commons/lang3/ConversionTest.java
index 59b372bd6..ec104e6dd 100644
--- a/src/test/java/org/apache/commons/lang3/ConversionTest.java
+++ b/src/test/java/org/apache/commons/lang3/ConversionTest.java
@@ -20,9 +20,13 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.Arrays;
+import java.util.SplittableRandom;
 import java.util.UUID;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 
 /**
@@ -413,6 +417,30 @@ public class ConversionTest {
 
     }
 
+    @Test
+    public void testBinaryToHexDigitReverse() {
+        final SplittableRandom rng = new SplittableRandom();
+        final boolean[] x = new boolean[8];
+        for (int i = 0; i < 100; i++) {
+            Conversion.longToBinary(rng.nextLong(), 0, x, 0, 8);
+            for (int j = 1; j <= 8; j++) {
+                final boolean[] a = Arrays.copyOf(x, j);
+                final boolean[] b = a.clone();
+                ArrayUtils.reverse(b);
+                for (int k = 0; k < j; k++) {
+                    assertEquals(Conversion.binaryToHexDigit(a, k),
+                            Conversion.binaryBeMsb0ToHexDigit(b, k));
+                }
+            }
+        }
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {-1, 8, 99})
+    public void binaryBeMsb0ToHexDigitPosOutsideArray(int index) {
+        assertThrows(IndexOutOfBoundsException.class,
+                () -> Conversion.binaryBeMsb0ToHexDigit(new boolean[8], index));
+    }
     /**
      * Tests {@link Conversion#intToHexDigit(int)}.
      */