diff --git a/src/bitmap/mod.rs b/src/bitmap/mod.rs
index 703fc1dd407..1ee5c3f3018 100644
--- a/src/bitmap/mod.rs
+++ b/src/bitmap/mod.rs
@@ -9,32 +9,3 @@ mod bitmap_ops;
 pub use bitmap_ops::*;
 
 pub mod utils;
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn subslicing_gives_correct_null_count() {
-        let mut base = MutableBitmap::new();
-        base.push(false);
-        base.push(true);
-        base.push(true);
-        base.push(false);
-        base.push(false);
-        base.push(true);
-        base.push(true);
-        base.push(true);
-
-        let base = Bitmap::from(base);
-        assert_eq!(base.null_count(), 3);
-
-        let view1 = base.clone().slice(0, 1);
-        let view2 = base.slice(1, 7);
-        assert_eq!(view1.null_count(), 1);
-        assert_eq!(view2.null_count(), 2);
-
-        let view3 = view2.slice(0, 1);
-        assert_eq!(view3.null_count(), 0);
-    }
-}
diff --git a/src/bitmap/utils/fmt.rs b/src/bitmap/utils/fmt.rs
index ca6b417e60f..9575cf18c99 100644
--- a/src/bitmap/utils/fmt.rs
+++ b/src/bitmap/utils/fmt.rs
@@ -70,46 +70,3 @@ pub fn fmt(
     }
     f.write_char(']')
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    struct A<'a>(&'a [u8], usize, usize);
-    impl<'a> std::fmt::Debug for A<'a> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            fmt(self.0, self.1, self.2, f)
-        }
-    }
-
-    #[test]
-    fn test_debug() -> std::fmt::Result {
-        assert_eq!(format!("{:?}", A(&[1], 0, 0)), "[]");
-        assert_eq!(format!("{:?}", A(&[0b11000001], 0, 8)), "[0b11000001]");
-        assert_eq!(
-            format!("{:?}", A(&[0b11000001, 1], 0, 9)),
-            "[0b11000001, 0b_______1]"
-        );
-        assert_eq!(format!("{:?}", A(&[1], 0, 2)), "[0b______01]");
-        assert_eq!(format!("{:?}", A(&[1], 1, 2)), "[0b_____00_]");
-        assert_eq!(format!("{:?}", A(&[1], 2, 2)), "[0b____00__]");
-        assert_eq!(format!("{:?}", A(&[1], 3, 2)), "[0b___00___]");
-        assert_eq!(format!("{:?}", A(&[1], 4, 2)), "[0b__00____]");
-        assert_eq!(format!("{:?}", A(&[1], 5, 2)), "[0b_00_____]");
-        assert_eq!(format!("{:?}", A(&[1], 6, 2)), "[0b00______]");
-        assert_eq!(
-            format!("{:?}", A(&[0b11000001, 1], 1, 9)),
-            "[0b1100000_, 0b______01]"
-        );
-        // extra bytes are ignored
-        assert_eq!(
-            format!("{:?}", A(&[0b11000001, 1, 1, 1], 1, 9)),
-            "[0b1100000_, 0b______01]"
-        );
-        assert_eq!(
-            format!("{:?}", A(&[0b11000001, 1, 1], 2, 16)),
-            "[0b110000__, 0b00000001, 0b______01]"
-        );
-        Ok(())
-    }
-}
diff --git a/src/types/bit_chunk.rs b/src/types/bit_chunk.rs
index 22f677aae4a..030a91fcc4f 100644
--- a/src/types/bit_chunk.rs
+++ b/src/types/bit_chunk.rs
@@ -103,8 +103,7 @@ impl<T: BitChunk> Iterator for BitChunkIter<T> {
 // a mathematical invariant of this iterator
 unsafe impl<T: BitChunk> crate::trusted_len::TrustedLen for BitChunkIter<T> {}
 
-/// An [`Iterator<Item=usize>`] over a [`BitChunk`].
-/// This iterator returns the postion of bit set.
+/// An [`Iterator<Item=usize>`] over a [`BitChunk`] returning the index of each bit set in the chunk
 /// Refer: https://lemire.me/blog/2018/03/08/iterating-over-set-bits-quickly-simd-edition/
 /// # Example
 /// ```
@@ -154,27 +153,3 @@ impl<T: BitChunk> Iterator for BitChunkOnes<T> {
 // # Safety
 // a mathematical invariant of this iterator
 unsafe impl<T: BitChunk> crate::trusted_len::TrustedLen for BitChunkOnes<T> {}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_basic1() {
-        let a = [0b00000001, 0b00010000]; // 0th and 13th entry
-        let a = u16::from_ne_bytes(a);
-        let iter = BitChunkIter::new(a, 16);
-        let r = iter.collect::<Vec<_>>();
-        assert_eq!(r, (0..16).map(|x| x == 0 || x == 12).collect::<Vec<_>>(),);
-    }
-
-    #[test]
-    fn test_ones() {
-        let a = [0b00000001, 0b00010000]; // 0th and 13th entry
-        let a = u16::from_ne_bytes(a);
-        let mut iter = BitChunkOnes::new(a);
-        assert_eq!(iter.size_hint(), (2, Some(2)));
-        assert_eq!(iter.next(), Some(0));
-        assert_eq!(iter.next(), Some(12));
-    }
-}
diff --git a/tests/it/bitmap/mod.rs b/tests/it/bitmap/mod.rs
index 2151c7b3bb0..af0c030f5c9 100644
--- a/tests/it/bitmap/mod.rs
+++ b/tests/it/bitmap/mod.rs
@@ -108,3 +108,17 @@ fn not() {
     let expected = create_bitmap([0b00010101], 6);
     assert_eq!(!&lhs, expected);
 }
+
+#[test]
+fn subslicing_gives_correct_null_count() {
+    let base = Bitmap::from([false, true, true, false, false, true, true, true]);
+    assert_eq!(base.null_count(), 3);
+
+    let view1 = base.clone().slice(0, 1);
+    let view2 = base.slice(1, 7);
+    assert_eq!(view1.null_count(), 1);
+    assert_eq!(view2.null_count(), 2);
+
+    let view3 = view2.slice(0, 1);
+    assert_eq!(view3.null_count(), 0);
+}
diff --git a/tests/it/bitmap/utils/fmt.rs b/tests/it/bitmap/utils/fmt.rs
new file mode 100644
index 00000000000..36e748bfe1b
--- /dev/null
+++ b/tests/it/bitmap/utils/fmt.rs
@@ -0,0 +1,40 @@
+use arrow2::bitmap::utils::fmt;
+
+struct A<'a>(&'a [u8], usize, usize);
+
+impl<'a> std::fmt::Debug for A<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        fmt(self.0, self.1, self.2, f)
+    }
+}
+
+#[test]
+fn test_debug() -> std::fmt::Result {
+    assert_eq!(format!("{:?}", A(&[1], 0, 0)), "[]");
+    assert_eq!(format!("{:?}", A(&[0b11000001], 0, 8)), "[0b11000001]");
+    assert_eq!(
+        format!("{:?}", A(&[0b11000001, 1], 0, 9)),
+        "[0b11000001, 0b_______1]"
+    );
+    assert_eq!(format!("{:?}", A(&[1], 0, 2)), "[0b______01]");
+    assert_eq!(format!("{:?}", A(&[1], 1, 2)), "[0b_____00_]");
+    assert_eq!(format!("{:?}", A(&[1], 2, 2)), "[0b____00__]");
+    assert_eq!(format!("{:?}", A(&[1], 3, 2)), "[0b___00___]");
+    assert_eq!(format!("{:?}", A(&[1], 4, 2)), "[0b__00____]");
+    assert_eq!(format!("{:?}", A(&[1], 5, 2)), "[0b_00_____]");
+    assert_eq!(format!("{:?}", A(&[1], 6, 2)), "[0b00______]");
+    assert_eq!(
+        format!("{:?}", A(&[0b11000001, 1], 1, 9)),
+        "[0b1100000_, 0b______01]"
+    );
+    // extra bytes are ignored
+    assert_eq!(
+        format!("{:?}", A(&[0b11000001, 1, 1, 1], 1, 9)),
+        "[0b1100000_, 0b______01]"
+    );
+    assert_eq!(
+        format!("{:?}", A(&[0b11000001, 1, 1], 2, 16)),
+        "[0b110000__, 0b00000001, 0b______01]"
+    );
+    Ok(())
+}
diff --git a/tests/it/bitmap/utils/mod.rs b/tests/it/bitmap/utils/mod.rs
index e92f31124ca..1ebce6f7f87 100644
--- a/tests/it/bitmap/utils/mod.rs
+++ b/tests/it/bitmap/utils/mod.rs
@@ -6,6 +6,7 @@ use crate::bitmap::bitmap_strategy;
 
 mod bit_chunks_exact;
 mod chunk_iter;
+mod fmt;
 mod iterator;
 mod slice_iterator;
 mod zip_validity;
diff --git a/tests/it/main.rs b/tests/it/main.rs
index 96515ebaf66..4c9448ea81a 100644
--- a/tests/it/main.rs
+++ b/tests/it/main.rs
@@ -4,6 +4,7 @@ mod buffer;
 mod ffi;
 mod scalar;
 mod temporal_conversions;
+mod types;
 
 mod io;
 mod test_util;
diff --git a/tests/it/types.rs b/tests/it/types.rs
new file mode 100644
index 00000000000..7dfa07cc167
--- /dev/null
+++ b/tests/it/types.rs
@@ -0,0 +1,20 @@
+use arrow2::types::{BitChunkIter, BitChunkOnes};
+
+#[test]
+fn test_basic1() {
+    let a = [0b00000001, 0b00010000]; // 0th and 13th entry
+    let a = u16::from_ne_bytes(a);
+    let iter = BitChunkIter::new(a, 16);
+    let r = iter.collect::<Vec<_>>();
+    assert_eq!(r, (0..16).map(|x| x == 0 || x == 12).collect::<Vec<_>>(),);
+}
+
+#[test]
+fn test_ones() {
+    let a = [0b00000001, 0b00010000]; // 0th and 13th entry
+    let a = u16::from_ne_bytes(a);
+    let mut iter = BitChunkOnes::new(a);
+    assert_eq!(iter.size_hint(), (2, Some(2)));
+    assert_eq!(iter.next(), Some(0));
+    assert_eq!(iter.next(), Some(12));
+}