diff --git a/src/common.rs b/src/common.rs
index eb69a16..e34ed48 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -161,24 +161,25 @@ mod tests {
         }
 
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "WARNING: A mock (from embedded-hal-mock) was dropped without calling the `.done()` method. See https://github.com/dbrgn/embedded-hal-mock/issues/34 for more details."
+        )]
         fn panic_if_drop_not_called() {
             let expectations = [0u8, 1u8];
             let mut mock: Generic<u8> = Generic::new(&expectations);
             assert_eq!(mock.next(), Some(0u8));
             assert_eq!(mock.next(), Some(1u8));
-            // Note: done() not called
         }
 
         #[test]
-        #[should_panic]
+        #[should_panic(expected = "The `.done()` method was called twice!")]
         fn panic_if_drop_called_twice() {
             let expectations = [0u8, 1u8];
             let mut mock: Generic<u8> = Generic::new(&expectations);
             assert_eq!(mock.next(), Some(0u8));
             assert_eq!(mock.next(), Some(1u8));
             mock.done();
-            mock.done(); // This will panic
+            mock.done();
         }
     }
 }
diff --git a/src/eh0/i2c.rs b/src/eh0/i2c.rs
index fcb6844..d3c8398 100644
--- a/src/eh0/i2c.rs
+++ b/src/eh0/i2c.rs
@@ -338,37 +338,41 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[1, 2]`,\n right: `[1, 3]`: i2c::write data does not match expectation"
+    )]
     fn write_data_mismatch() {
         let expectations = [Transaction::write(0xaa, vec![1, 2])];
         let mut i2c = Mock::new(&expectations);
 
-        let _ = i2c.write(0xaa, &vec![1, 3]); // Panics because unexpected data was written
+        let _ = i2c.write(0xaa, &vec![1, 3]);
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `Read`,\n right: `Write`: i2c::write unexpected mode"
+    )]
     fn transaction_type_mismatch() {
         let expectations = [Transaction::read(0xaa, vec![10, 12])];
         let mut i2c = Mock::new(&expectations);
 
         let mut buff = vec![0; 2];
-        let _ = i2c.write(0xaa, &mut buff); // Panics because it's a write, not a read
+        let _ = i2c.write(0xaa, &mut buff);
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(expected = "i2c::write_read address mismatch")]
     fn address_mismatch() {
         let expectations = [Transaction::write_read(0xbb, vec![1, 2], vec![3, 4])];
         let mut i2c = Mock::new(&expectations);
 
         let v = vec![1, 2];
         let mut buff = vec![0; 2];
-        let _ = i2c.write_read(0xaa, &v, &mut buff); // Panics because an unexpected address was used
+        let _ = i2c.write_read(0xaa, &v, &mut buff);
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(expected = "Not all expectations consumed")]
     fn unconsumed_expectations() {
         let expectations = [
             Transaction::write(0xaa, vec![10, 12]),
@@ -378,7 +382,7 @@ mod test {
 
         i2c.write(0xaa, &vec![10, 12]).unwrap();
 
-        i2c.done(); // Panics because not all transactions were consumed
+        i2c.done();
     }
 
     #[test]
@@ -428,21 +432,25 @@ mod test {
 
         /// The transaction mode should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `Write`,\n right: `Read`: i2c::read unexpected mode"
+        )]
         fn write_wrong_mode() {
             let mut i2c = Mock::new(&[Transaction::write(0xaa, vec![10, 12])
                 .with_error(MockError::Io(IoErrorKind::Other))]);
             let mut buf = vec![0; 2];
-            let _ = i2c.read(0xaa, &mut buf); // Panics because it's a read, not a write
+            let _ = i2c.read(0xaa, &mut buf);
         }
 
         /// The transaction bytes should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 13]`: i2c::write data does not match expectation"
+        )]
         fn write_wrong_data() {
             let mut i2c = Mock::new(&[Transaction::write(0xaa, vec![10, 12])
                 .with_error(MockError::Io(IoErrorKind::Other))]);
-            let _ = i2c.write(0xaa, &vec![10, 13]); // Panics because unexpected data was written
+            let _ = i2c.write(0xaa, &vec![10, 13]);
         }
 
         #[test]
@@ -471,12 +479,14 @@ mod test {
 
         /// The transaction bytes should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 13]`: i2c::write_read write data does not match expectation"
+        )]
         fn write_read_wrong_data() {
             let mut i2c = Mock::new(&[Transaction::write_read(0xaa, vec![10, 12], vec![13, 14])
                 .with_error(MockError::Io(IoErrorKind::Other))]);
             let mut buf = vec![0; 2];
-            let _ = i2c.write_read(0xaa, &vec![10, 13], &mut buf); // Panics because unexpected data was written
+            let _ = i2c.write_read(0xaa, &vec![10, 13], &mut buf);
         }
     }
 }
diff --git a/src/eh0/serial.rs b/src/eh0/serial.rs
index 228d19b..c7055a4 100644
--- a/src/eh0/serial.rs
+++ b/src/eh0/serial.rs
@@ -515,7 +515,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "unsatisfied expectations")]
+    #[should_panic(expected = "serial mock has unsatisfied expectations after call to done")]
     fn test_serial_mock_blocking_write_not_enough() {
         let ts = [Transaction::write_many([0xAB, 0xCD, 0xEF, 0x00])];
         let mut ser = Mock::new(&ts);
@@ -524,7 +524,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "serial::write expected to write")]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `18`,\n right: `20`: serial::write expected to write 18 but actually wrote 20"
+    )]
     fn test_serial_mock_wrong_write() {
         let ts = [Transaction::write(0x12)];
         let mut ser = Mock::new(&ts);
@@ -548,7 +550,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "unsatisfied expectations")]
+    #[should_panic(expected = "serial mock has unsatisfied expectations after call to done")]
     fn test_serial_mock_pending_transactions() {
         let ts = [Transaction::read(0x54)];
         let mut ser = Mock::new(&ts);
@@ -556,7 +558,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "unsatisfied expectations")]
+    #[should_panic(expected = "serial mock has unsatisfied expectations after call to done")]
     fn test_serial_mock_reuse_pending_transactions() {
         let ts = [Transaction::read(0x54)];
         let mut ser = Mock::new(&ts);
@@ -568,7 +570,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "expected to perform a serial transaction 'Read(")]
+    #[should_panic(
+        expected = "expected to perform a serial transaction 'Read(84)' but instead did a write of 119"
+    )]
     fn test_serial_mock_expected_read() {
         let ts = [Transaction::read(0x54)];
         let mut ser = Mock::new(&ts);
@@ -576,7 +580,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "expected to perform a serial transaction 'Write(")]
+    #[should_panic(
+        expected = "expected to perform a serial transaction 'Write(84)' but instead did a flush"
+    )]
     fn test_serial_mock_expected_write() {
         let ts = [Transaction::write(0x54)];
         let mut ser = Mock::new(&ts);
@@ -584,7 +590,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "expected to perform a serial transaction 'Flush'")]
+    #[should_panic(
+        expected = "expected to perform a serial transaction 'Flush', but instead did a read"
+    )]
     fn test_serial_mock_expected_flush() {
         let ts = [Transaction::flush()];
         let mut ser: Mock<u128> = Mock::new(&ts);
@@ -610,7 +618,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "serial::write expected to write 42 but actually wrote 23")]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `42`,\n right: `23`: serial::write expected to write 42 but actually wrote 23"
+    )]
     fn test_serial_mock_write_error_wrong_data() {
         let error = nb::Error::Other(MockError::Io(io::ErrorKind::NotConnected));
         let ts = [Transaction::write_error(42, error.clone())];
diff --git a/src/eh0/spi.rs b/src/eh0/spi.rs
index 7e40309..c6ca265 100644
--- a/src/eh0/spi.rs
+++ b/src/eh0/spi.rs
@@ -323,7 +323,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write data does not match expectation"
+    )]
     fn test_spi_mock_write_err() {
         let expectations = [Transaction::write(vec![10, 12])];
         let mut spi = Mock::new(&expectations);
@@ -334,7 +336,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write_iter data does not match expectation"
+    )]
     fn test_spi_mock_write_iter_err() {
         let expectations = [Transaction::write(vec![10, 12])];
         let mut spi = Mock::new(&expectations);
@@ -345,7 +349,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[12, 15]`,\n right: `[12, 13]`"
+    )]
     fn test_spi_mock_transfer_err() {
         let expectations = [Transaction::transfer(vec![10, 12], vec![12, 15])];
         let mut spi = Mock::new(&expectations);
@@ -359,7 +365,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[1, 2]`,\n right: `[10, 12]`: spi::write data does not match expectation"
+    )]
     fn test_spi_mock_transfer_response_err() {
         let expectations = [Transaction::transfer(vec![1, 2], vec![3, 4, 5])];
         let mut spi = Mock::new(&expectations);
@@ -373,7 +381,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `Transfer`,\n right: `Write`: spi::write unexpected mode"
+    )]
     fn test_spi_mock_mode_err() {
         let expectations = [Transaction::transfer(vec![10, 12], vec![])];
         let mut spi = Mock::new(&expectations);
@@ -384,7 +394,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write data does not match expectation"
+    )]
     fn test_spi_mock_multiple_transaction_err() {
         let expectations = [
             Transaction::write(vec![10, 12]),
diff --git a/src/eh1/i2c.rs b/src/eh1/i2c.rs
index 1fe9a16..b73da1a 100644
--- a/src/eh1/i2c.rs
+++ b/src/eh1/i2c.rs
@@ -384,37 +384,45 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[1, 2]`,\n right: `[1, 3]`: i2c::write data does not match expectation"
+    )]
     fn write_data_mismatch() {
         let expectations = [Transaction::write(0xaa, vec![1, 2])];
         let mut i2c = Mock::new(&expectations);
 
-        i2c.write(0xaa, &vec![1, 3]).unwrap(); // Panics because unexpected data was written
+        i2c.write(0xaa, &vec![1, 3]).unwrap();
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `Read`,\n right: `Write`: i2c::write unexpected mode"
+    )]
     fn transaction_type_mismatch() {
         let expectations = [Transaction::read(0xaa, vec![10, 12])];
         let mut i2c = Mock::new(&expectations);
 
         let mut buff = vec![0; 2];
-        i2c.write(0xaa, &mut buff).unwrap(); // Panics because it's a write, not a read
+        i2c.write(0xaa, &mut buff).unwrap();
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `187`,\n right: `170`: i2c::write_read address mismatch"
+    )]
     fn address_mismatch() {
         let expectations = [Transaction::write_read(0xbb, vec![1, 2], vec![3, 4])];
         let mut i2c = Mock::new(&expectations);
 
         let v = vec![1, 2];
         let mut buff = vec![0; 2];
-        i2c.write_read(0xaa, &v, &mut buff).unwrap(); // Panics because an unexpected address was used
+        i2c.write_read(0xaa, &v, &mut buff).unwrap();
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `Read`,\n right: `Write`: i2c::write unexpected mode"
+    )]
     fn test_i2c_mock_mode_err() {
         let expectations = [Transaction::read(0xaa, vec![10, 12])];
         let mut i2c = Mock::new(&expectations);
@@ -425,7 +433,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(expected = "Not all expectations consumed")]
     fn unconsumed_expectations() {
         let expectations = [
             Transaction::write(0xaa, vec![10, 12]),
@@ -435,7 +443,7 @@ mod test {
 
         i2c.write(0xaa, &vec![10, 12]).unwrap();
 
-        i2c.done(); // Panics because not all transactions were consumed
+        i2c.done();
     }
 
     #[test]
@@ -485,21 +493,25 @@ mod test {
 
         /// The transaction mode should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `Write`,\n right: `Read`: i2c::read unexpected mode"
+        )]
         fn write_wrong_mode() {
             let mut i2c =
                 Mock::new(&[Transaction::write(0xaa, vec![10, 12]).with_error(ErrorKind::Other)]);
             let mut buf = vec![0; 2];
-            let _ = i2c.read(0xaa, &mut buf); // Panics because it's a read, not a write
+            let _ = i2c.read(0xaa, &mut buf);
         }
 
         /// The transaction bytes should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 13]`: i2c::write data does not match expectation"
+        )]
         fn write_wrong_data() {
             let mut i2c =
                 Mock::new(&[Transaction::write(0xaa, vec![10, 12]).with_error(ErrorKind::Other)]);
-            let _ = i2c.write(0xaa, &vec![10, 13]); // Panics because unexpected data was written
+            let _ = i2c.write(0xaa, &vec![10, 13]);
         }
 
         #[test]
@@ -517,7 +529,9 @@ mod test {
 
         /// The transaction mode should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `Read`,\n right: `Write`: i2c::write unexpected mode"
+        )]
         fn read_wrong_mode() {
             let mut i2c =
                 Mock::new(&[Transaction::read(0xaa, vec![10, 12]).with_error(ErrorKind::Other)]);
@@ -537,7 +551,9 @@ mod test {
 
         /// The transaction mode should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `WriteRead`,\n right: `Write`: i2c::write unexpected mode"
+        )]
         fn write_read_wrong_mode() {
             let mut i2c = Mock::new(&[Transaction::write_read(0xaa, vec![10, 12], vec![13, 14])
                 .with_error(ErrorKind::Other)]);
@@ -546,7 +562,9 @@ mod test {
 
         /// The transaction bytes should still be validated.
         #[test]
-        #[should_panic]
+        #[should_panic(
+            expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 13]`: i2c::write_read write data does not match expectation"
+        )]
         fn write_read_wrong_data() {
             let mut i2c = Mock::new(&[Transaction::write_read(0xaa, vec![10, 12], vec![13, 14])
                 .with_error(ErrorKind::Other)]);
diff --git a/src/eh1/serial.rs b/src/eh1/serial.rs
index a21b38a..c317783 100644
--- a/src/eh1/serial.rs
+++ b/src/eh1/serial.rs
@@ -517,7 +517,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "unsatisfied expectations")]
+    #[should_panic(expected = "serial mock has unsatisfied expectations after call to done")]
     fn test_serial_mock_blocking_write_not_enough() {
         use embedded_hal::serial::Write as BWrite;
         let ts = [Transaction::write_many([0xAB, 0xCD, 0xEF, 0x00])];
@@ -527,7 +527,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "serial::write expected to write")]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `18`,\n right: `20`: serial::write expected to write 18 but actually wrote 20"
+    )]
     fn test_serial_mock_wrong_write() {
         let ts = [Transaction::write(0x12)];
         let mut ser = Mock::new(&ts);
@@ -552,7 +554,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "unsatisfied expectations")]
+    #[should_panic(expected = "serial mock has unsatisfied expectations after call to done")]
     fn test_serial_mock_pending_transactions() {
         let ts = [Transaction::read(0x54)];
         let mut ser = Mock::new(&ts);
@@ -560,7 +562,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "unsatisfied expectations")]
+    #[should_panic(expected = "serial mock has unsatisfied expectations after call to done")]
     fn test_serial_mock_reuse_pending_transactions() {
         let ts = [Transaction::read(0x54)];
         let mut ser = Mock::new(&ts);
@@ -572,7 +574,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "expected to perform a serial transaction 'Read(")]
+    #[should_panic(
+        expected = "expected to perform a serial transaction 'Read(84)' but instead did a write of 119"
+    )]
     fn test_serial_mock_expected_read() {
         use embedded_hal::serial::Write as BWrite;
         let ts = [Transaction::read(0x54)];
@@ -581,7 +585,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "expected to perform a serial transaction 'Write(")]
+    #[should_panic(
+        expected = "expected to perform a serial transaction 'Write(84)' but instead did a flush"
+    )]
     fn test_serial_mock_expected_write() {
         let ts = [Transaction::write(0x54)];
         let mut ser = Mock::new(&ts);
@@ -589,7 +595,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "expected to perform a serial transaction 'Flush'")]
+    #[should_panic(
+        expected = "expected to perform a serial transaction 'Flush', but instead did a read"
+    )]
     fn test_serial_mock_expected_flush() {
         let ts = [Transaction::flush()];
         let mut ser: Mock<u128> = Mock::new(&ts);
@@ -615,7 +623,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic(expected = "serial::write expected to write 42 but actually wrote 23")]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `42`,\n right: `23`: serial::write expected to write 42 but actually wrote 23"
+    )]
     fn test_serial_mock_write_error_wrong_data() {
         let error = nb::Error::Other(ErrorKind::Parity);
         let ts = [Transaction::write_error(42, error.clone())];
diff --git a/src/eh1/spi.rs b/src/eh1/spi.rs
index c28a911..4a8996e 100644
--- a/src/eh1/spi.rs
+++ b/src/eh1/spi.rs
@@ -772,7 +772,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write data does not match expectation"
+    )]
     fn test_spi_mock_write_err() {
         use embedded_hal::spi::SpiBusWrite;
 
@@ -786,7 +788,9 @@ mod test {
 
     #[tokio::test]
     #[cfg(feature = "embedded-hal-async")]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write data does not match expectation"
+    )]
     async fn test_async_spi_mock_write_err() {
         use embedded_hal_async::spi::SpiBusWrite;
 
@@ -799,7 +803,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[12, 15]`,\n right: `[12, 13]`"
+    )]
     fn test_spi_mock_transfer_err() {
         use embedded_hal::spi::SpiBus;
 
@@ -816,7 +822,9 @@ mod test {
 
     #[tokio::test]
     #[cfg(feature = "embedded-hal-async")]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[12, 15]`,\n right: `[12, 13]`"
+    )]
     async fn test_async_spi_mock_transfer_err() {
         use embedded_hal_async::spi::SpiBus;
 
@@ -832,7 +840,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[1, 2]`,\n right: `[10, 12]`: spi::write data does not match expectation"
+    )]
     fn test_spi_mock_transfer_response_err() {
         use embedded_hal::spi::SpiBus;
 
@@ -849,7 +859,9 @@ mod test {
 
     #[tokio::test]
     #[cfg(feature = "embedded-hal-async")]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[1, 2]`,\n right: `[10, 12]`: spi::write data does not match expectation"
+    )]
     async fn test_async_spi_mock_transfer_response_err() {
         use embedded_hal_async::spi::SpiBus;
 
@@ -865,7 +877,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "(left == right)`\n  left: `TransferInplace`,\n right: `Write`: spi::write unexpected mode"
+    )]
     fn test_spi_mock_mode_err() {
         use embedded_hal::spi::SpiBusWrite;
 
@@ -879,7 +893,9 @@ mod test {
 
     #[tokio::test]
     #[cfg(feature = "embedded-hal-async")]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `TransferInplace`,\n right: `Write`: spi::write unexpected mode"
+    )]
     async fn test_async_spi_mock_mode_err() {
         use embedded_hal_async::spi::SpiBusWrite;
 
@@ -892,7 +908,9 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write data does not match expectation"
+    )]
     fn test_spi_mock_multiple_transaction_err() {
         use embedded_hal::spi::SpiBusWrite;
 
@@ -909,7 +927,9 @@ mod test {
 
     #[tokio::test]
     #[cfg(feature = "embedded-hal-async")]
-    #[should_panic]
+    #[should_panic(
+        expected = "assertion failed: `(left == right)`\n  left: `[10, 12]`,\n right: `[10, 12, 12]`: spi::write data does not match expectation"
+    )]
     async fn test_async_spi_mock_multiple_transaction_err() {
         use embedded_hal_async::spi::SpiBusWrite;