diff --git a/src/assert.rs b/src/assert.rs
new file mode 100644
index 0000000..12ef751
--- /dev/null
+++ b/src/assert.rs
@@ -0,0 +1,67 @@
+use std::fmt::Debug;
+
+pub fn assert<T>(v: T) -> Assert<T> {
+    Assert { v }
+}
+
+pub struct Assert<T> {
+    v: T,
+}
+
+impl Assert<bool> {
+    #[track_caller]
+    pub fn is_true(self) {
+        assert!(self.v);
+    }
+    #[track_caller]
+    pub fn is_false(self) {
+        assert!(!self.v);
+    }
+}
+
+impl<T: Debug> Assert<T> {
+    #[track_caller]
+    pub fn equals<U: Debug>(self, other: U)
+    where
+        T: PartialEq<U>,
+    {
+        assert_eq!(self.v, other);
+    }
+    #[track_caller]
+    pub fn not_equals<U: Debug>(self, other: U)
+    where
+        T: PartialEq<U>,
+    {
+        assert_ne!(self.v, other);
+    }
+}
+
+impl<T: AsRef<str>> Assert<T> {
+    #[track_caller]
+    pub fn contains(self, other: &str) {
+        assert!(self.v.as_ref().contains(other), "pattern '{other}' not found in string: {}", self.v.as_ref());
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn assert_bool() {
+        assert(true).is_true();
+        assert(false).is_false();
+    }
+
+    #[test]
+    fn assert_equal() {
+        assert(1).equals(1);
+        assert(2).not_equals(1);
+    }
+
+    #[test]
+    fn assert_str() {
+        assert("uwu owo").contains("uwu");
+        assert("uwu owo".to_owned()).contains("uwu");
+    }
+}
diff --git a/src/hashmaps/mod.rs b/src/hashmaps/mod.rs
index 5726bf7..66379bb 100644
--- a/src/hashmaps/mod.rs
+++ b/src/hashmaps/mod.rs
@@ -71,7 +71,7 @@ mod tests {
         for count in [1, 10, 100, 1000, 10_000, 100_000] {
             test_many::<M, _>(count, RandomState::new());
         }
-        test_many::<M, _>(5000, BuildHasherDefault::<CollidingHasher>::default());
+        test_many::<M, _>(1000, BuildHasherDefault::<CollidingHasher>::default());
     }
 
     fn test_many<M: HashMapFamily, H: BuildHasher>(count: usize, h: H) {
diff --git a/src/lib.rs b/src/lib.rs
index cfa10ab..c976be9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,7 @@ pub mod sendsync;
 pub mod thin_u128;
 pub mod unroll_int;
 pub mod unsized_clone;
+pub mod assert;
 
 pub mod safe_extern {
     pub use pm::safe_extern;