diff --git a/src/bytes.rs b/src/bytes.rs
index db6cba73e..e1559311b 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -2586,35 +2586,51 @@ fn original_capacity_from_repr(repr: usize) -> usize {
 
 #[test]
 fn test_original_capacity_to_repr() {
-    for &cap in &[0, 1, 16, 1000] {
-        assert_eq!(0, original_capacity_to_repr(cap));
-    }
+    assert_eq!(original_capacity_to_repr(0), 0);
 
-    for &cap in &[1024, 1025, 1100, 2000, 2047] {
-        assert_eq!(1, original_capacity_to_repr(cap));
-    }
+    let max_width = 32;
 
-    for &cap in &[2048, 2049] {
-        assert_eq!(2, original_capacity_to_repr(cap));
-    }
+    for width in 1..(max_width + 1) {
+        let cap = 1 << width - 1;
+
+        let expected = if width < MIN_ORIGINAL_CAPACITY_WIDTH {
+            0
+        } else if width < MAX_ORIGINAL_CAPACITY_WIDTH {
+            width - MIN_ORIGINAL_CAPACITY_WIDTH
+        } else {
+            MAX_ORIGINAL_CAPACITY_WIDTH - MIN_ORIGINAL_CAPACITY_WIDTH
+        };
 
-    // TODO: more
+        assert_eq!(original_capacity_to_repr(cap), expected);
 
-    for &cap in &[65536, 65537, 68000, 1 << 17, 1 << 18, 1 << 20, 1 << 30] {
-        assert_eq!(7, original_capacity_to_repr(cap), "cap={}", cap);
+        if width > 1 {
+            assert_eq!(original_capacity_to_repr(cap + 1), expected);
+        }
+
+        //  MIN_ORIGINAL_CAPACITY_WIDTH must be bigger than 7 to pass tests below
+        if width == MIN_ORIGINAL_CAPACITY_WIDTH + 1 {
+            assert_eq!(original_capacity_to_repr(cap - 24), expected - 1);
+            assert_eq!(original_capacity_to_repr(cap + 76), expected);
+        } else if width == MIN_ORIGINAL_CAPACITY_WIDTH + 2 {
+            assert_eq!(original_capacity_to_repr(cap - 1), expected - 1);
+            assert_eq!(original_capacity_to_repr(cap - 48), expected - 1);
+        }
     }
 }
 
 #[test]
 fn test_original_capacity_from_repr() {
     assert_eq!(0, original_capacity_from_repr(0));
-    assert_eq!(1024, original_capacity_from_repr(1));
-    assert_eq!(1024 * 2, original_capacity_from_repr(2));
-    assert_eq!(1024 * 4, original_capacity_from_repr(3));
-    assert_eq!(1024 * 8, original_capacity_from_repr(4));
-    assert_eq!(1024 * 16, original_capacity_from_repr(5));
-    assert_eq!(1024 * 32, original_capacity_from_repr(6));
-    assert_eq!(1024 * 64, original_capacity_from_repr(7));
+
+    let min_cap = 1 << MIN_ORIGINAL_CAPACITY_WIDTH;
+
+    assert_eq!(min_cap, original_capacity_from_repr(1));
+    assert_eq!(min_cap * 2, original_capacity_from_repr(2));
+    assert_eq!(min_cap * 4, original_capacity_from_repr(3));
+    assert_eq!(min_cap * 8, original_capacity_from_repr(4));
+    assert_eq!(min_cap * 16, original_capacity_from_repr(5));
+    assert_eq!(min_cap * 32, original_capacity_from_repr(6));
+    assert_eq!(min_cap * 64, original_capacity_from_repr(7));
 }
 
 unsafe impl Send for Inner {}