diff --git a/src/func/instances/effect.rs b/src/func/instances/effect.rs
index 2b6a24d..3ae3e1d 100644
--- a/src/func/instances/effect.rs
+++ b/src/func/instances/effect.rs
@@ -169,7 +169,7 @@ mod effect_tests {
     #[derive(Clone, Debug, PartialEq)]
     enum TestEffect {
         Pure,
-        Sample,
+        Sample(i32),
         Parallel(Arc<Self>, Arc<Self>),
         Sequential(Arc<Self>, Arc<Self>),
     }
@@ -182,7 +182,7 @@ mod effect_tests {
         fn simplify(&self) -> Arc<Self> {
             match self {
                 Self::Pure => Self::Pure.into(),
-                Self::Sample => Self::Sample.into(),
+                Self::Sample(x) => Self::Sample(*x).into(),
                 Self::Parallel(a, b) if a.is_pure() => b.clone(),
                 Self::Parallel(a, b) if b.is_pure() => a.clone(),
                 Self::Sequential(a, b) if a.is_pure() => b.clone(),
@@ -241,7 +241,19 @@ mod effect_tests {
         ) {
             f(Arc::new(|a| WithEffect {
                 value: a,
-                effect: TestEffect::Sample,
+                effect: TestEffect::Sample(0),
+            }));
+            f(Arc::new(|a| WithEffect {
+                value: a,
+                effect: TestEffect::Sample(1),
+            }));
+            f(Arc::new(|a| WithEffect {
+                value: a,
+                effect: TestEffect::Sample(2),
+            }));
+            f(Arc::new(|a| WithEffect {
+                value: a,
+                effect: TestEffect::Sample(3),
             }));
         }
     }
@@ -255,4 +267,9 @@ mod effect_tests {
     fn shared_follows_laws() {
         test_suite::shared_follows_laws::<T>().unwrap();
     }
+
+    #[test]
+    fn local_follows_laws() {
+        test_suite::local_follows_laws::<T>().unwrap();
+    }
 }
diff --git a/src/func/instances/result.rs b/src/func/instances/result.rs
index acb0428..bf0f6d8 100644
--- a/src/func/instances/result.rs
+++ b/src/func/instances/result.rs
@@ -299,4 +299,9 @@ mod result_tests {
     fn fail_follows_laws() {
         test_suite::fail_functor_follows_laws::<T, _>().unwrap();
     }
+
+    #[test]
+    fn local_follows_laws() {
+        test_suite::local_follows_laws::<T>().unwrap();
+    }
 }
diff --git a/src/func/test_suite.rs b/src/func/test_suite.rs
index 6b239de..f7b0e04 100644
--- a/src/func/test_suite.rs
+++ b/src/func/test_suite.rs
@@ -1,6 +1,7 @@
 use std::sync::Arc;
 
 use super::fail::*;
+use super::local::*;
 use super::shared::*;
 use super::tests::*;
 use super::*;
@@ -144,3 +145,13 @@ pub fn fail_functor_follows_laws<'a, T: Functor<'a> + FailTestSuite<'a, E>, E: '
     });
     res
 }
+
+pub fn local_follows_laws<'a, T: LocalFunctor<'a> + Monad<'a> + FunctorTestSuite<'a>>() -> R {
+    let mut res = R::default();
+    T::sample(|pa| {
+        T::sample(|pb| {
+            res += local_self_composes::<T, _>(|| pa(pb(2)));
+        })
+    });
+    res
+}
diff --git a/src/func/tests.rs b/src/func/tests.rs
index 11c0e1a..d936831 100644
--- a/src/func/tests.rs
+++ b/src/func/tests.rs
@@ -3,6 +3,8 @@ use std::{
     ops::{Add, AddAssign},
 };
 
+use local::LocalFunctor;
+
 use super::applicative_select::*;
 use super::controlflow::*;
 use super::fail::*;
@@ -491,3 +493,17 @@ pub fn fmap_keeps_fail<
 ) -> R {
     T::eqr("fmap fail", T::fmap(T::fail(e0()), f), T::fail(e0()))
 }
+
+pub fn local_self_composes<
+    'a,
+    T: LocalFunctor<'a> + Monad<'a> + Eqr<'a>,
+    A: 'a + Send + Debug + PartialOrd,
+>(
+    ffa0: impl Fn() -> T::F<T::F<A>>,
+) -> R {
+    T::eqr(
+        "local self",
+        T::join(T::stuff::<_, T>(T::stuff::<_, T>(ffa0()))),
+        T::join(ffa0()),
+    )
+}