diff --git a/sha1-checked/tests/mod.rs b/sha1-checked/tests/mod.rs
index 20c12a12..72708117 100644
--- a/sha1-checked/tests/mod.rs
+++ b/sha1-checked/tests/mod.rs
@@ -30,7 +30,8 @@ fn shambles_1() {
         &include_bytes!("./data/sha-mbles-1.bin")[..],
         hex!("8ac60ba76f1999a1ab70223f225aefdc78d4ddc0"),
         hex!("4f3d9be4a472c4dae83c6314aa6c36a064c1fd14"),
-    )
+        false,
+    );
 }
 
 #[test]
@@ -39,7 +40,8 @@ fn shambles_2() {
         &include_bytes!("./data/sha-mbles-2.bin")[..],
         hex!("8ac60ba76f1999a1ab70223f225aefdc78d4ddc0"),
         hex!("9ed5d77a4f48be1dbf3e9e15650733eb850897f2"),
-    )
+        false,
+    );
 }
 
 #[test]
@@ -48,7 +50,8 @@ fn shattered_1() {
         &include_bytes!("./data/shattered-1.pdf")[..],
         hex!("38762cf7f55934b34d179ae6a4c80cadccbb7f0a"),
         hex!("16e96b70000dd1e7c85b8368ee197754400e58ec"),
-    )
+        false,
+    );
 }
 
 #[test]
@@ -57,10 +60,23 @@ fn shattered_2() {
         &include_bytes!("./data/shattered-2.pdf")[..],
         hex!("38762cf7f55934b34d179ae6a4c80cadccbb7f0a"),
         hex!("e1761773e6a35916d99f891b77663e6405313587"),
+        false,
+    );
+}
+
+#[test]
+fn reducedsha_coll() {
+    collision_test(
+        &include_bytes!("./data/sha1_reducedsha_coll.bin")[..],
+        hex!("a56374e1cf4c3746499bc7c0acb39498ad2ee185"),
+        hex!("dd39885a2a5d8f59030b451e00cb45da9f9d3828"),
+        true,
     )
 }
 
-fn collision_test(input: &[u8], hash: [u8; 20], mitigated_hash: [u8; 20]) {
+fn collision_test(input: &[u8], hash: [u8; 20], mitigated_hash: [u8; 20], reduced_rounds: bool) {
+    let has_collision = true;
+
     // No detection.
     let mut ctx = Sha1::builder().detect_collision(false).build();
     ctx.update(input);
@@ -69,24 +85,33 @@ fn collision_test(input: &[u8], hash: [u8; 20], mitigated_hash: [u8; 20]) {
     assert_eq!(&d.hash()[..], hash,);
 
     // No mitigation.
-    let mut ctx = Sha1::builder().safe_hash(false).build();
+    let mut ctx = Sha1::builder()
+        .safe_hash(false)
+        .reduced_round_collision(reduced_rounds)
+        .build();
     ctx.update(input);
 
     let d = ctx.try_finalize();
-    assert!(d.has_collision());
+    assert_eq!(d.has_collision(), has_collision);
     assert_eq!(&d.hash()[..], hash);
 
     // No mitigation, no optimization.
-    let mut ctx = Sha1::builder().safe_hash(false).use_ubc(false).build();
+    let mut ctx = Sha1::builder()
+        .safe_hash(false)
+        .use_ubc(false)
+        .reduced_round_collision(reduced_rounds)
+        .build();
     ctx.update(input);
     let d = ctx.try_finalize();
-    assert!(d.has_collision());
+    assert_eq!(d.has_collision(), has_collision);
     assert_eq!(&d.hash()[..], hash);
 
     // With mitigation.
-    let mut ctx = Sha1::new();
+    let mut ctx = Sha1::builder()
+        .reduced_round_collision(reduced_rounds)
+        .build();
     ctx.update(input);
     let d = ctx.try_finalize();
-    assert!(d.has_collision());
+    assert_eq!(d.has_collision(), has_collision);
     assert_eq!(&d.hash()[..], mitigated_hash);
 }