diff --git a/crates/wasm_interp/src/tests/test_mem.rs b/crates/wasm_interp/src/tests/test_mem.rs
index 09f54d8e54..9d24e0df0d 100644
--- a/crates/wasm_interp/src/tests/test_mem.rs
+++ b/crates/wasm_interp/src/tests/test_mem.rs
@@ -72,13 +72,14 @@ fn test_memory_fill() {
     state.value_store.push(Value::I32(SIZE));
 
     // before the instruction, the memory is all zeros
-    let slice = &state.memory[destination as usize..][..SIZE as usize];
-    assert_eq!(slice, &[0; SIZE as usize]);
+    let memory_before = &state.memory[destination as usize..][..SIZE as usize];
+    assert_eq!(memory_before, &[0; SIZE as usize]);
 
     state.execute_next_instruction(&module).unwrap();
 
-    let slice = &state.memory[destination as usize..][..SIZE as usize];
-    assert_eq!(slice, &[byte_value as u8; SIZE as usize])
+    // after the fill, the same memory range is now all 0xAA bytes
+    let memory_after = &state.memory[destination as usize..][..SIZE as usize];
+    assert_eq!(memory_after, &[byte_value as u8; SIZE as usize])
 }
 
 #[test]
@@ -103,16 +104,19 @@ fn test_memory_copy() {
     state.value_store.push(Value::I32(source));
     state.value_store.push(Value::I32(SIZE));
 
-    // before the instruction, the memory is all zeros
-    let slice = &mut state.memory[source as usize..][..SIZE as usize];
-    assert_eq!(slice, &[0; SIZE as usize]);
+    // fill the source slice with 0xAA bytes
+    let source_slice = &mut state.memory[source as usize..][..SIZE as usize];
+    source_slice.fill(0xAA);
 
-    slice.fill(0xAA);
+    // before the copy, the destination slice is all 0x00 bytes
+    let dest_slice = &state.memory[destination as usize..][..SIZE as usize];
+    assert_eq!(dest_slice, &[0x00; SIZE as usize]);
 
     state.execute_next_instruction(&module).unwrap();
 
-    let slice = &state.memory[destination as usize..][..SIZE as usize];
-    assert_eq!(slice, &[0xAA; SIZE as usize])
+    // after the copy, the destination slice is all 0xAA bytes
+    let dest_slice = &state.memory[destination as usize..][..SIZE as usize];
+    assert_eq!(dest_slice, &[0xAA; SIZE as usize])
 }
 
 fn test_load(load_op: OpCode, ty: ValueType, data: &[u8], addr: u32, offset: u32) -> Value {