test: add v2 happy path non-essential tests

add tests to cover fallback, redirect, content-negotiation and etag caching scenarios

packages/ic-response-verification-test-utils/Cargo.toml

@@ -23,3 +23,4 @@ serde = { version = "1.0.152", features = ["derive"]}
 # https://docs.rs/getrandom/latest/getrandom/#webassembly-support
 rand = "0.8.5"
 getrandom = { version = "0.2.8", features = ["js"] }
+flate2 = "1.0.25"

packages/ic-response-verification-test-utils/src/encoding.rs

@@ -1,5 +1,8 @@
 use base64::{engine::general_purpose, Engine as _};
+use flate2::write::{DeflateEncoder, GzEncoder};
+use flate2::Compression;
 use serde::Serialize;
+use std::io::Write;
 
 pub fn base64_encode(data: &[u8]) -> String {
     general_purpose::STANDARD.encode(data)
@@ -17,3 +20,17 @@ pub fn leb_encode_timestamp(timestamp: u128) -> Vec<u8> {
     leb128::write::unsigned(&mut encoded_time, timestamp as u64).unwrap();
     encoded_time
 }
+
+pub fn gzip_encode(data: &[u8]) -> Vec<u8> {
+    let mut encoder = GzEncoder::new(Vec::new(), Compression::default());
+    encoder.write_all(data).unwrap();
+
+    encoder.finish().unwrap()
+}
+
+pub fn deflate_encode(data: &[u8]) -> Vec<u8> {
+    let mut encoder = DeflateEncoder::new(Vec::new(), Compression::default());
+    encoder.write_all(data).unwrap();
+
+    encoder.finish().unwrap()
+}