diff --git a/tests/basics/int_bytes_notimpl.py b/tests/basics/int_bytes_notimpl.py
new file mode 100644
index 0000000000..b47d6ab584
--- /dev/null
+++ b/tests/basics/int_bytes_notimpl.py
@@ -0,0 +1,9 @@
+try:
+    print((10).to_bytes(1, "big"))
+except Exception as e:
+    print(type(e))
+
+try:
+    print(int.from_bytes(b"\0", "big"))
+except Exception as e:
+    print(type(e))
diff --git a/tests/basics/int_bytes_notimpl.py.exp b/tests/basics/int_bytes_notimpl.py.exp
new file mode 100644
index 0000000000..d1bf338eb6
--- /dev/null
+++ b/tests/basics/int_bytes_notimpl.py.exp
@@ -0,0 +1,2 @@
+<class 'NotImplementedError'>
+<class 'NotImplementedError'>
diff --git a/tests/extmod/uctypes_ptr_le.py b/tests/extmod/uctypes_ptr_le.py
index 4bff585171..d0216dfb81 100644
--- a/tests/extmod/uctypes_ptr_le.py
+++ b/tests/extmod/uctypes_ptr_le.py
@@ -14,7 +14,7 @@ desc = {
 bytes = b"01"
 
 addr = uctypes.addressof(bytes)
-buf = addr.to_bytes(uctypes.sizeof(desc))
+buf = addr.to_bytes(uctypes.sizeof(desc), "little")
 
 S = uctypes.struct(uctypes.addressof(buf), desc, uctypes.LITTLE_ENDIAN)
 
diff --git a/tests/extmod/uctypes_ptr_native_le.py b/tests/extmod/uctypes_ptr_native_le.py
index 0d02cfdc8e..6f011c3c2b 100644
--- a/tests/extmod/uctypes_ptr_native_le.py
+++ b/tests/extmod/uctypes_ptr_native_le.py
@@ -15,7 +15,7 @@ desc = {
 bytes = b"01"
 
 addr = uctypes.addressof(bytes)
-buf = addr.to_bytes(uctypes.sizeof(desc))
+buf = addr.to_bytes(uctypes.sizeof(desc), "little")
 
 S = uctypes.struct(uctypes.addressof(buf), desc, uctypes.NATIVE)