diff --git a/src/traits.rs b/src/traits.rs
index 018a62c..6f3462b 100644
--- a/src/traits.rs
+++ b/src/traits.rs
@@ -34,23 +34,3 @@
         (self.len_utf8() as u32).into()
     }
 }
-
-// assertion shape from static_assertions::assert_impl_all!
-const _: fn() = || {
-    use std::borrow::Cow;
-
-    fn assert_impl<T: TextSized>() {}
-
-    assert_impl::<&String>();
-    assert_impl::<&Cow<str>>();
-
-    struct StringLike {}
-    impl Deref for StringLike {
-        type Target = str;
-        fn deref(&self) -> &str {
-            unreachable!()
-        }
-    }
-
-    assert_impl::<&StringLike>();
-};
diff --git a/tests/constructors.rs b/tests/constructors.rs
new file mode 100644
index 0000000..eba587b
--- /dev/null
+++ b/tests/constructors.rs
@@ -0,0 +1,31 @@
+use {
+    std::{borrow::Cow, ops::Deref},
+    text_size::*,
+};
+
+struct StringLike<'a>(&'a str);
+
+impl Deref for StringLike<'_> {
+    type Target = str;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[test]
+fn main() {
+    let s = "";
+    let _ = TextSize::of(&s);
+
+    let s = String::new();
+    let _ = TextSize::of(&s);
+
+    let s = Cow::Borrowed("");
+    let _ = TextSize::of(&s);
+
+    let s = Cow::Owned(String::new());
+    let _ = TextSize::of(&s);
+
+    let s = StringLike("");
+    let _ = TextSize::of(&s);
+}