fix bitmap new_trued (#1580)

src/bitmap/immutable.rs

@@ -307,7 +307,7 @@ impl Bitmap {
         // just set each byte to u8::MAX
         // we will not access data with index >= length
         let bytes = vec![0b11111111u8; length.saturating_add(7) / 8];
-        unsafe { Bitmap::from_inner_unchecked(Arc::new(bytes.into()), 0, length, length) }
+        unsafe { Bitmap::from_inner_unchecked(Arc::new(bytes.into()), 0, length, 0) }
     }
 
     /// Counts the nulls (unset bits) starting from `offset` bits and for `length` bits.

tests/it/bitmap/immutable.rs

@@ -32,6 +32,25 @@ fn as_slice_offset_middle() {
     assert_eq!(length, 5);
 }
 
+#[test]
+fn new_constant() {
+    let b = Bitmap::new_constant(true, 9);
+    let (slice, offset, length) = b.as_slice();
+    assert_eq!(slice[0], 0b11111111);
+    assert!((slice[1] & 0b00000001) > 0);
+    assert_eq!(offset, 0);
+    assert_eq!(length, 9);
+    assert_eq!(b.unset_bits(), 0);
+
+    let b = Bitmap::new_constant(false, 9);
+    let (slice, offset, length) = b.as_slice();
+    assert_eq!(slice[0], 0b00000000);
+    assert!((slice[1] & 0b00000001) == 0);
+    assert_eq!(offset, 0);
+    assert_eq!(length, 9);
+    assert_eq!(b.unset_bits(), 9);
+}
+
 #[test]
 fn debug() {
     let b = Bitmap::from([true, true, false, true, true, true, true, true, true]);