diff --git a/capsules/extra/src/test/hmac_sha256.rs b/capsules/extra/src/test/hmac_sha256.rs
index d4d620fd03..a9d0ce3dd7 100644
--- a/capsules/extra/src/test/hmac_sha256.rs
+++ b/capsules/extra/src/test/hmac_sha256.rs
@@ -7,7 +7,7 @@
 
 use crate::hmac_sha256::HmacSha256Software;
 use crate::sha256::Sha256Software;
-use capsules_core::test::capsule_test::{CapsuleTest, CapsuleTestClient};
+use capsules_core::test::capsule_test::{CapsuleTest, CapsuleTestClient, CapsuleTestError};
 use kernel::hil::digest;
 use kernel::hil::digest::HmacSha256;
 use kernel::hil::digest::{DigestData, DigestHash};
@@ -66,28 +66,54 @@ impl digest::ClientData<32> for TestHmacSha256 {
         unimplemented!()
     }
 
-    fn add_mut_data_done(&self, _result: Result<(), ErrorCode>, data: SubSliceMut<'static, u8>) {
+    fn add_mut_data_done(&self, result: Result<(), ErrorCode>, data: SubSliceMut<'static, u8>) {
         self.data.replace(data.take());
 
+        match result {
+            Ok(()) => {}
+            Err(e) => {
+                kernel::debug!("HmacSha256Test: failed to add data: {:?}", e);
+                self.client.map(|client| {
+                    client.done(Err(CapsuleTestError::ErrorCode(e)));
+                });
+                return;
+            }
+        }
+
         let r = self.hmac.run(self.digest.take().unwrap());
-        if r.is_err() {
-            panic!("HmacSha256Test: failed to run HMAC: {:?}", r);
+        match r {
+            Ok(()) => {}
+            Err((e, d)) => {
+                kernel::debug!("HmacSha256Test: failed to run HMAC: {:?}", e);
+
+                self.digest.replace(d);
+                self.client.map(|client| {
+                    client.done(Err(CapsuleTestError::ErrorCode(e)));
+                });
+            }
         }
     }
 }
 
 impl digest::ClientHash<32> for TestHmacSha256 {
     fn hash_done(&self, _result: Result<(), ErrorCode>, digest: &'static mut [u8; 32]) {
+        let mut error = false;
         for i in 0..32 {
             if self.correct[i] != digest[i] {
-                panic!("HmacSha256Test: incorrect HMAC output!");
+                error = true;
             }
         }
-        kernel::debug!("HMAC-SHA256 matches!");
-
-        self.client.map(|client| {
-            client.done(Ok(()));
-        });
+        if !error {
+            kernel::debug!("HMAC-SHA256 matches!");
+            self.client.map(|client| {
+                client.done(Ok(()));
+            });
+        } else {
+            kernel::debug!("HmacSha256Test: incorrect HMAC output!");
+            self.client.map(|client| {
+                client.done(Err(CapsuleTestError::IncorrectResult));
+            });
+        }
     }
 }
 
diff --git a/capsules/extra/src/test/siphash24.rs b/capsules/extra/src/test/siphash24.rs
index 08b99353f5..a60da765ae 100644
--- a/capsules/extra/src/test/siphash24.rs
+++ b/capsules/extra/src/test/siphash24.rs
@@ -8,7 +8,7 @@
 //! Digest trait.
 
 use crate::sip_hash::SipHasher24;
-use capsules_core::test::capsule_test::{CapsuleTest, CapsuleTestClient};
+use capsules_core::test::capsule_test::{CapsuleTest, CapsuleTestClient, CapsuleTestError};
 use kernel::hil::hasher::{Client, Hasher};
 use kernel::utilities::cells::OptionalCell;
 use kernel::utilities::cells::TakeCell;
@@ -74,7 +74,11 @@ impl Client<8> for TestSipHash24 {
         self.hasher.clear_data();
 
         self.client.map(|client| {
-            let res = if matches { Ok(()) } else { Err(()) };
+            let res = if matches {
+                Ok(())
+            } else {
+                Err(CapsuleTestError::IncorrectResult)
+            };
             client.done(res);
         });
     }