Move mod tests to BitMapTest

Consolidate the cases from EnhancedDoubleHasherTest and BitMapTest. Use Long.remainderUnsigned as the reference result.
apache · Jun 13, 2023 · 1624bdb · 1624bdb
1 parent 81834a6
commit 1624bdb
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Showing 2 changed files with 25 additions and 20 deletions.
diff --git a/src/test/java/org/apache/commons/collections4/bloomfilter/BitMapTest.java b/src/test/java/org/apache/commons/collections4/bloomfilter/BitMapTest.java
@@ -104,18 +104,34 @@ public final void testContains() {
         assertTrue(BitMap.contains(ary, 64));
     }
 
-    private void assertMod(long l, int i) {
-        assertEquals(Math.floorMod(l, i), BitMap.mod(l, i));
+    @Test
+    public void testMod() {
+        for (final long dividend : new long[] {0, -1, -2, -3, -6378683, -23567468136887892L,
+            Long.MIN_VALUE, 345, 678686, 67868768686878924L, Long.MAX_VALUE, Long.MAX_VALUE - 1}) {
+            for (final int divisor : new int[] {1, 2, 3, 5, 13, Integer.MAX_VALUE, Integer.MAX_VALUE - 1}) {
+                assertMod(dividend, divisor);
+            }
+        }
     }
 
     @Test
-    public final void testMod() {
-        assertMod(Long.MAX_VALUE, Integer.MAX_VALUE);
-        assertMod(Long.MAX_VALUE, Integer.MAX_VALUE-1);
-        assertThrows(ArithmeticException.class, () -> BitMap.mod(Long.MAX_VALUE, 0));
-        assertMod(Long.MAX_VALUE-1, Integer.MAX_VALUE);
-        assertMod(Long.MAX_VALUE-1, Integer.MAX_VALUE-1);
-        assertMod(0, Integer.MAX_VALUE);
+    public void testModEdgeCases() {
+        for (final long dividend : new long[] {0, -1, 1, Long.MAX_VALUE}) {
+            assertThrows(ArithmeticException.class, () -> BitMap.mod(dividend, 0));
+        }
         assertNotEquals(Math.floorMod(5, -1), BitMap.mod(5, -1));
     }
+
+    /**
+     * Assert the {@link BitMap#mod(long, int)} method functions as an unsigned modulus.
+     *
+     * @param dividend the dividend
+     * @param divisor the divisor
+     */
+    private void assertMod(long dividend, int divisor) {
+        assertTrue(divisor > 0 && divisor <= Integer.MAX_VALUE,
+            "Incorrect usage. Divisor must be strictly positive.");
+        assertEquals((int) Long.remainderUnsigned(dividend, divisor), BitMap.mod(dividend, divisor),
+            () -> String.format("failure with dividend=%s and divisor=%s.", dividend, divisor));
+    }
 }
diff --git a/src/test/java/org/apache/commons/collections4/bloomfilter/EnhancedDoubleHasherTest.java b/src/test/java/org/apache/commons/collections4/bloomfilter/EnhancedDoubleHasherTest.java
@@ -93,15 +93,4 @@ public void testByteConstructor() {
         // test empty buffer
         assertThrows(IllegalArgumentException.class, () -> new EnhancedDoubleHasher(new byte[0]));
     }
-
-    @Test
-    void testModEdgeCases() {
-        for (final long dividend : new long[] {-1, -2, -3, -6378683, -23567468136887892L, Long.MIN_VALUE, 345, 678686,
-            67868768686878924L, Long.MAX_VALUE}) {
-            for (final int divisor : new int[] {1, 2, 3, 5, 13, Integer.MAX_VALUE}) {
-                assertEquals((int) Long.remainderUnsigned(dividend, divisor), BitMap.mod(dividend, divisor),
-                        () -> String.format("failure with dividend=%s and divisor=%s.", dividend, divisor));
-            }
-        }
-    }
 }