runtime: Validate pointer access instead of using coersion on tests

runtime/test/src/test.rs

@@ -993,12 +993,11 @@ fn test_safe_null_ptr_read(api_version: Version) {
         api_version,
     );
 
-    let result_ptr: AscPtr<AscBigInt> = module.invoke_export0("safeNullPtrRead");
-    let result: BigInt = asc_get(&module, result_ptr).unwrap();
-    assert_eq!(result, BigInt::from(2));
+    module.invoke_export0_void("safeNullPtrRead");
 }
 
 #[tokio::test]
+#[should_panic(expected = "Failed to sum BigInts because left hand side is 'null'")]
 async fn safe_null_ptr_read_0_0_5() {
     test_safe_null_ptr_read(API_VERSION_0_0_5);
 }

runtime/test/wasm_test/api_version_0_0_5/null_ptr_read.ts

@@ -57,11 +57,10 @@ class SafeBigInt extends Uint8Array {
     }
 
     @operator('+')
-    plus(other: SafeBigInt | null): SafeBigInt {
-        let x = this ? this : SafeBigInt.fromI32(0);
-        let y = other ? other : SafeBigInt.fromI32(0);
+    plus(other: SafeBigInt): SafeBigInt {
+        assert(this != null, "Failed to sum BigInts because left hand side is 'null'");
 
-        return changetype<SafeBigInt>(bigInt.plus(changetype<BigInt>(x), changetype<BigInt>(y)));
+        return changetype<SafeBigInt>(bigInt.plus(changetype<BigInt>(this), changetype<BigInt>(other)));
     }
 }
 
@@ -71,13 +70,13 @@ class Wrapper2 {
     ) {}
 }
 
-export function safeNullPtrRead(): SafeBigInt {
+export function safeNullPtrRead(): void {
     let x = SafeBigInt.fromI32(2);
     let y: SafeBigInt | null = null;
 
     let wrapper2 = new Wrapper2(y);
 
+    // Breaks as well, but by our assertion, before getting into
+    // the Rust code.
     wrapper2.n = wrapper2.n + x;
-
-    return wrapper2.n!;
 }