Error Saving QR Code from qrcode dfinity example via test case

Developers Rust
1

I am trying to write a test function for this canister function examples/rust/qrcode/src/qrcode_backend/src/lib.rs at bf706c78e75a4a06a9f195adddfa100b27c718bd · dfinity/examples · GitHub

use candid::{decode_one, CandidType, Encode, Principal};
use pocket_ic::{PocketIc, WasmResult};
use serde::Deserialize;
use std::fs;
use std::fs::File;
use std::io::prelude::*;

#[derive(CandidType, Deserialize)]
struct Options {
    add_logo: bool,
    add_gradient: bool,
    add_transparency: Option<bool>,
}

#[derive(CandidType, Deserialize)]
struct QrError {
    message: String,
}

#[derive(CandidType, Deserialize)]
enum QrResult {
    Image(Vec<u8>),
    Err(QrError),
}

const BACKEND_WASM: &str = "target/wasm32-unknown-unknown/release/qrcode_backend.wasm";

fn setup() -> (PocketIc, Principal) {
    let pic = PocketIc::new();

    let backend_canister = pic.create_canister();
    pic.add_cycles(backend_canister, 2_000_000_000_000); // 2T Cycles
    let wasm = fs::read(BACKEND_WASM).expect("Wasm file not found, run 'dfx build'.");
    pic.install_canister(backend_canister, wasm, vec![], None);
    (pic, backend_canister)
}

#[test]
fn test_qrcode_query() {
    let (pic, backend_canister) = setup();

    let Ok(WasmResult::Reply(response)) = pic.query_call(
        backend_canister,
        Principal::anonymous(),
        "qrcode_query",
        Encode!(
            &"https://facebook.com",
            &Options {
                add_gradient: true,
                add_logo: true,
                add_transparency: Some(false)
            }
        )
        .unwrap(),
    ) else {
        panic!("Expected reply");
    };

    // Writing the response to a file
    let mut file = File::create("qr.png").expect("Unable to create file");
    let result: Vec<u8> = decode_one(&response).unwrap();
    file.write_all(&result)
        .expect("Unable to write data to file");
}

unfortunately i am receiving an error during cargo test posted below:

75d555575d75d555575df57f1d95abaebaeaaaabaebaeaaaabaebaeaaaabaebaeaff3a2a575d75d555575d75d555575d75d555575d75d5ff7554aebaeaaaabaebaeaaaabaebaeaaaabaebaeaaaffeba85c75d555575d75d555575d75d555575d75d555ffd751b9eaaaabaebaeaaaabaebaeaaaabaebaeaaaabfeafa372d555575d75d555575d75d555575d75d55557fd5f47e5aaabaebaeaaaabaebaeaaaabaebaeaaaabaefabf8eca55575d75d555575d75d555575d75d555575df57f1d95abaebaeaaaabaebaeaaaabaebaeaaaabaebaeaff3a2a575d75d555575d75d555575d75d555575d75d5ff7554aebaeaaaabaebaeaaaabaebaeaaaabaebaeaaaffeba85c75d555575d75d555575d75d555575d75d555ffd751b9eaaaabaebaeaaaabaebaeaaaabaebaeaaaabfeafa372d555575d75d555575d75d555575d75d55557fd5f47e5aaabaebaeaaaabaebaeaaaabaebaeaaaabaefabf8eca55575d75d555575d75d555575d75d555575df57f1dff080281916e68494dd60000000049454e44ae426082
table: type table0 = variant { 3_456_837 : table1; 1_352_044_347 : table2 }
type table1 = record { 2_584_819_143 : text }
type table2 = blob
wire_type: variant { 3_456_837 : table1; 1_352_044_347 : table2 }, expect_type: blob

Caused by:
    0: Fail to decode argument 0 from table0 to blob
    1: Subtyping error: Type mismatch at /home/eli/.cargo/registry/src/index.crates.io-6f17d22bba15001f/candid-0.10.10/src/de.rs:882)
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    test_qrcode_query

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.07s

From my understanding, the response is still encrypted and needs to be decoded first, but when i’m trying to decode, it gives me the error provided above.

For now my end goal is to try to save the qrcode as png file