diff --git a/crates/loro-core/src/container/map/tests.rs b/crates/loro-core/src/container/map/tests.rs
index bb56d635..dcbd0274 100644
--- a/crates/loro-core/src/container/map/tests.rs
+++ b/crates/loro-core/src/container/map/tests.rs
@@ -23,15 +23,16 @@ fn basic() {
     assert_eq!(*container.get_value(), LoroValue::Map(ans));
 }
 
-#[cfg(not(no_proptest))]
 mod map_proptest {
+    use crate::tests::PROPTEST_FACTOR_10;
+
     use super::*;
 
     proptest! {
         #[test]
         fn insert(
-            key in prop::collection::vec("[a-z]", 0..22),
-            value in prop::collection::vec(gen_insert_value(), 0..22)
+            key in prop::collection::vec("[a-z]", 0..10 * PROPTEST_FACTOR_10),
+            value in prop::collection::vec(gen_insert_value(), 0..10 * PROPTEST_FACTOR_10)
         ) {
             let mut loro = LoroCore::default();
             let accessor = loro.store.get_accessor();
diff --git a/crates/loro-core/src/dag/test.rs b/crates/loro-core/src/dag/test.rs
index 5f96d41d..19377021 100644
--- a/crates/loro-core/src/dag/test.rs
+++ b/crates/loro-core/src/dag/test.rs
@@ -519,11 +519,10 @@ mod find_common_ancestors {
     }
 }
 
-#[cfg(not(no_proptest))]
 mod find_common_ancestors_proptest {
     use proptest::prelude::*;
 
-    use crate::{array_mut_ref, unsafe_array_mut_ref};
+    use crate::{array_mut_ref, tests::PROPTEST_FACTOR_10, unsafe_array_mut_ref};
 
     use super::*;
 
@@ -545,69 +544,53 @@ mod find_common_ancestors_proptest {
     proptest! {
         #[test]
         fn test_2dags(
-            before_merged_insertions in prop::collection::vec(gen_interaction(2), 0..100),
-            after_merged_insertions in prop::collection::vec(gen_interaction(2), 0..100)
+            before_merged_insertions in prop::collection::vec(gen_interaction(2), 0..100 * PROPTEST_FACTOR_10),
+            after_merged_insertions in prop::collection::vec(gen_interaction(2), 0..100 * PROPTEST_FACTOR_10)
         ) {
             test_single_common_ancestor(2, before_merged_insertions, after_merged_insertions)?;
         }
 
         #[test]
         fn test_4dags(
-            before_merged_insertions in prop::collection::vec(gen_interaction(4), 0..100),
-            after_merged_insertions in prop::collection::vec(gen_interaction(4), 0..100)
+            before_merged_insertions in prop::collection::vec(gen_interaction(4), 0..100 * PROPTEST_FACTOR_10),
+            after_merged_insertions in prop::collection::vec(gen_interaction(4), 0..100 * PROPTEST_FACTOR_10)
         ) {
             test_single_common_ancestor(4, before_merged_insertions, after_merged_insertions)?;
         }
 
         #[test]
         fn test_10dags(
-            before_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100),
-            after_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100)
+            before_merged_insertions in prop::collection::vec(gen_interaction(10), 0..10 * PROPTEST_FACTOR_10 * PROPTEST_FACTOR_10),
+            after_merged_insertions in prop::collection::vec(gen_interaction(10), 0..10 * PROPTEST_FACTOR_10 * PROPTEST_FACTOR_10)
         ) {
             test_single_common_ancestor(10, before_merged_insertions, after_merged_insertions)?;
         }
 
         #[test]
         fn test_mul_ancestors_5dags(
-            before_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100),
-            after_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100)
+            before_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100 * PROPTEST_FACTOR_10),
+            after_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100 * PROPTEST_FACTOR_10)
         ) {
             test_mul_ancestors::<2>(5, before_merged_insertions, after_merged_insertions)?;
         }
 
         #[test]
         fn test_mul_ancestors_10dags(
-            before_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100),
-            after_merged_insertions in prop::collection::vec(gen_interaction(10), 0..100)
+            before_merged_insertions in prop::collection::vec(gen_interaction(10), 0..10 * PROPTEST_FACTOR_10 * PROPTEST_FACTOR_10),
+            after_merged_insertions in prop::collection::vec(gen_interaction(10), 0..10 * PROPTEST_FACTOR_10 * PROPTEST_FACTOR_10)
         ) {
             test_mul_ancestors::<3>(10, before_merged_insertions, after_merged_insertions)?;
         }
 
         #[test]
         fn test_mul_ancestors_15dags_2(
-            before_merged_insertions in prop::collection::vec(gen_interaction(15), 0..50),
-            after_merged_insertions in prop::collection::vec(gen_interaction(15), 0..50)
+            before_merged_insertions in prop::collection::vec(gen_interaction(15), 0..10 * PROPTEST_FACTOR_10 * PROPTEST_FACTOR_10),
+            after_merged_insertions in prop::collection::vec(gen_interaction(15), 0..10 * PROPTEST_FACTOR_10 * PROPTEST_FACTOR_10)
         ) {
             test_mul_ancestors::<5>(15, before_merged_insertions, after_merged_insertions)?;
         }
     }
 
-    #[test]
-    fn issue() {
-        if let Err(err) = test_mul_ancestors::<3>(
-            10,
-            vec![Interaction {
-                dag_idx: 2,
-                merge_with: Some(5),
-                len: 1,
-            }],
-            vec![],
-        ) {
-            println!("{}", err);
-            panic!();
-        }
-    }
-
     fn preprocess(interactions: &mut [Interaction], num: i32) {
         for interaction in interactions.iter_mut() {
             interaction.dag_idx %= num as usize;
diff --git a/crates/loro-core/src/lib.rs b/crates/loro-core/src/lib.rs
index 218d6082..5311d58e 100644
--- a/crates/loro-core/src/lib.rs
+++ b/crates/loro-core/src/lib.rs
@@ -21,7 +21,7 @@ mod smstring;
 mod snapshot;
 mod span;
 #[cfg(test)]
-mod tests;
+pub mod tests;
 mod value;
 
 pub(crate) mod macros;
diff --git a/crates/loro-core/src/tests/mod.rs b/crates/loro-core/src/tests/mod.rs
index 67005ab4..c96d20e7 100644
--- a/crates/loro-core/src/tests/mod.rs
+++ b/crates/loro-core/src/tests/mod.rs
@@ -1 +1,6 @@
 #![cfg(test)]
+
+#[cfg(feature = "fuzzing")]
+pub const PROPTEST_FACTOR_10: usize = 10;
+#[cfg(not(feature = "fuzzing"))]
+pub const PROPTEST_FACTOR_10: usize = 1;
diff --git a/crates/rle/src/lib.rs b/crates/rle/src/lib.rs
index 138044d3..fd7501ab 100644
--- a/crates/rle/src/lib.rs
+++ b/crates/rle/src/lib.rs
@@ -30,3 +30,5 @@ pub use crate::rle_vec::{RleVec, SearchResult, SliceIterator};
 pub mod rle_impl;
 pub use rle_tree::tree_trait::RleTreeTrait;
 pub use rle_tree::RleTree;
+#[cfg(test)]
+mod test;
diff --git a/crates/rle/src/rle_tree/test/notify_prop_test.rs b/crates/rle/src/rle_tree/test/notify_prop_test.rs
index 814c1a8c..b773b910 100644
--- a/crates/rle/src/rle_tree/test/notify_prop_test.rs
+++ b/crates/rle/src/rle_tree/test/notify_prop_test.rs
@@ -334,15 +334,16 @@ fn issue_5() {
     ])
 }
 
-#[cfg(not(no_proptest))]
 mod notify_proptest {
+    use crate::test::PROPTEST_FACTOR_10;
+
     use super::*;
     use proptest::prelude::*;
 
     proptest! {
         #[test]
         fn test_notify(
-            interactions in prop::collection::vec(gen_interaction(), 1..100),
+            interactions in prop::collection::vec(gen_interaction(), 1..20 * PROPTEST_FACTOR_10* PROPTEST_FACTOR_10),
         ) {
             test(&interactions);
         }
diff --git a/crates/rle/src/rle_tree/test/string_prop_test.rs b/crates/rle/src/rle_tree/test/string_prop_test.rs
index aaac112f..bd32157a 100644
--- a/crates/rle/src/rle_tree/test/string_prop_test.rs
+++ b/crates/rle/src/rle_tree/test/string_prop_test.rs
@@ -86,7 +86,7 @@ fn basic_string_op() {
 fn issue_0() {
     let mut tree: RleTree<CustomString, StringTreeTrait> = RleTree::default();
     let insert_keys = "0123456789abcdefghijklmnopq";
-    for i in 0..(1e5 as usize) {
+    for i in 0..(1e4 as usize * crate::test::PROPTEST_FACTOR_10) {
         let start = i % insert_keys.len();
         if i % 3 == 0 && tree.len() > 0 {
             let start = i % tree.len();
@@ -290,8 +290,9 @@ fn issue_delete() {
     ])
 }
 
-#[cfg(not(no_proptest))]
 mod string_proptest {
+    use crate::test::{PROPTEST_FACTOR_1, PROPTEST_FACTOR_10};
+
     use super::*;
     use proptest::prelude::*;
 
@@ -319,17 +320,16 @@ mod string_proptest {
     proptest! {
         #[test]
         fn test_tree_string_op_the_same(
-            interactions in prop::collection::vec(gen_interaction(), 1..50),
+            interactions in prop::collection::vec(gen_interaction(), 1..20 * PROPTEST_FACTOR_10 + PROPTEST_FACTOR_1 * 1000),
         ) {
             run_test(interactions);
         }
     }
 
-    #[cfg(slow_proptest)]
     proptest! {
         #[test]
         fn test_tree_string_op_the_same_slow(
-            interactions in prop::collection::vec(gen_interaction(), 1..2000),
+            interactions in prop::collection::vec(gen_interaction(), 1..20 * PROPTEST_FACTOR_10 + PROPTEST_FACTOR_1 * 1000),
         ) {
             let mut s = String::new();
             let mut tree = RleTree::default();
diff --git a/crates/rle/src/test.rs b/crates/rle/src/test.rs
new file mode 100644
index 00000000..698a5e74
--- /dev/null
+++ b/crates/rle/src/test.rs
@@ -0,0 +1,11 @@
+#![cfg(test)]
+
+#[cfg(feature = "fuzzing")]
+pub const PROPTEST_FACTOR_10: usize = 10;
+#[cfg(not(feature = "fuzzing"))]
+pub const PROPTEST_FACTOR_10: usize = 1;
+
+#[cfg(feature = "fuzzing")]
+pub const PROPTEST_FACTOR_1: usize = 1;
+#[cfg(not(feature = "fuzzing"))]
+pub const PROPTEST_FACTOR_1: usize = 0;