diff --git a/.github/workflows/bencher.yml b/.github/workflows/bencher.yml
index 51d41ded..3c44eea0 100644
--- a/.github/workflows/bencher.yml
+++ b/.github/workflows/bencher.yml
@@ -31,7 +31,6 @@ jobs:
           BENCHER_API_TOKEN: ${{ secrets.BENCHER_API_TOKEN }}
           BENCHER_CMD: cargo bench --all-features
           BENCHER_PROJECT: socketioxide
-          RUSTFLAGS: --cfg=socketioxide_test
 
   benchmark_pr:
     if: github.event_name == 'workflow_dispatch' && github.event.pull_request.head.repo.full_name == github.repository
@@ -62,4 +61,3 @@ jobs:
           BENCHER_API_TOKEN: ${{ secrets.BENCHER_API_TOKEN }}
           BENCHER_CMD: cargo bench --all-features
           BENCHER_PROJECT: socketioxide
-          RUSTFLAGS: --cfg=socketioxide_test
\ No newline at end of file
diff --git a/.github/workflows/github-ci.yml b/.github/workflows/github-ci.yml
index b2cf7f00..7d295d73 100644
--- a/.github/workflows/github-ci.yml
+++ b/.github/workflows/github-ci.yml
@@ -18,8 +18,6 @@ jobs:
           toolchain: stable
           components: rustfmt
       - run: cargo fmt --all -- --check
-        env:
-          RUSTFLAGS: --cfg=socketioxide_test
 
   test:
     runs-on: ubuntu-latest
@@ -39,8 +37,6 @@ jobs:
             target/
           key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
       - run: cargo test --tests --all-features --workspace
-        env:
-          RUSTFLAGS: --cfg=socketioxide_test
   udeps:
     runs-on: ubuntu-latest
     steps:
@@ -90,8 +86,6 @@ jobs:
 
       - name: check crates
         run: cargo check -p socketioxide -p engineioxide --all-features
-        env:
-          RUSTFLAGS: --cfg=socketioxide_test
 
   feature_set:
     runs-on: ubuntu-latest
@@ -188,8 +182,6 @@ jobs:
           --tests
           --message-format=json | clippy-sarif | tee rust-clippy-results.sarif | sarif-fmt
         continue-on-error: true
-        env:
-          RUSTFLAGS: --cfg=socketioxide_test
 
       - name: Upload analysis results to GitHub
         uses: github/codeql-action/upload-sarif@v3
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 4d9068f1..01a23ed8 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -16,7 +16,7 @@ today! As a contributor, here are the guidelines we would like you to follow:
 
 ## <a name="question"></a> Got a Question or Problem?
 
-Please open a discussion on the [Q&A discussions](https://github.com/totodore/socketioxide/discussions) page. 
+Please open a discussion on the [Q&A discussions](https://github.com/totodore/socketioxide/discussions) page.
 We want to keep GitHub Issues for bugs and feature requests. If you open an issue it will be moved to Discussions.
 
 ## <a name="issue"></a> Found a Bug?
@@ -139,11 +139,6 @@ You will need [rustc and cargo](www.rust-lang.org/tools/install).
     ```shell
     git clone https://github.com/totodore/socketioxide
     ```
-2. To test socketioxide don't forget to enable the flag `socketioxide_test` through the `RUSTFLAGS` environment variable:
-
-    ```shell
-    export RUSTFLAGS="--cfg socketioxide_test"
-    ```
 2. Depending on what you want to change, clone the [socketio/engine.io-protocol](https://github.com/socketio/engine.io-protocol) repo or the [socketio/socket.io-protocol](https://github.com/socketio/socket.io-protocol) repo or both
     ```shell
     git clone https://github.com/socketio/engine.io-protocol
@@ -261,4 +256,4 @@ The subject contains succinct description of the change:
 ### Body
 
 Just as in the **subject**, use the imperative, present tense: "change" not "changed" nor "changes".
-The body should include the motivation for the change and contrast this with previous behavior.
\ No newline at end of file
+The body should include the motivation for the change and contrast this with previous behavior.
diff --git a/engineioxide/Cargo.toml b/engineioxide/Cargo.toml
index 41ba0341..dde3f270 100644
--- a/engineioxide/Cargo.toml
+++ b/engineioxide/Cargo.toml
@@ -58,6 +58,7 @@ hyper-util = { workspace = true, features = ["tokio", "client-legacy"] }
 [features]
 v3 = ["memchr", "unicode-segmentation", "itoa"]
 tracing = ["dep:tracing"]
+__test_harness = []
 
 [[bench]]
 name = "packet_encode"
diff --git a/engineioxide/src/lib.rs b/engineioxide/src/lib.rs
index 14777b7a..142435cf 100644
--- a/engineioxide/src/lib.rs
+++ b/engineioxide/src/lib.rs
@@ -36,7 +36,8 @@ pub use crate::str::Str;
 pub use service::{ProtocolVersion, TransportType};
 pub use socket::{DisconnectReason, Socket};
 
-#[cfg(any(test, socketioxide_test))]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 pub use packet::*;
 
 pub mod config;
diff --git a/engineioxide/src/socket.rs b/engineioxide/src/socket.rs
index 430d8fa8..a1dd24e9 100644
--- a/engineioxide/src/socket.rs
+++ b/engineioxide/src/socket.rs
@@ -481,7 +481,8 @@ impl<D: Default + Send + Sync + 'static> std::fmt::Debug for Socket<D> {
     }
 }
 
-#[cfg(socketioxide_test)]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 impl<D> Drop for Socket<D>
 where
     D: Default + Send + Sync + 'static,
@@ -492,7 +493,8 @@ where
     }
 }
 
-#[cfg(any(socketioxide_test, test))]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 impl<D> Socket<D>
 where
     D: Default + Send + Sync + 'static,
diff --git a/socketioxide/Cargo.toml b/socketioxide/Cargo.toml
index 4b5c988c..6763bed2 100644
--- a/socketioxide/Cargo.toml
+++ b/socketioxide/Cargo.toml
@@ -42,6 +42,7 @@ v4 = ["engineioxide/v3"]
 tracing = ["dep:tracing", "engineioxide/tracing"]
 extensions = []
 state = ["dep:state"]
+__test_harness = ["engineioxide/__test_harness"]
 
 [dev-dependencies]
 engineioxide = { path = "../engineioxide", features = ["v3", "tracing"] }
diff --git a/socketioxide/src/client.rs b/socketioxide/src/client.rs
index d69d313d..a430f662 100644
--- a/socketioxide/src/client.rs
+++ b/socketioxide/src/client.rs
@@ -16,7 +16,7 @@ use tokio::sync::oneshot;
 use crate::adapter::Adapter;
 use crate::handler::ConnectHandler;
 use crate::ns::NamespaceCtr;
-use crate::parser::{self, CommonParser, Parse, Parser, TransportPayload};
+use crate::parser::{self, Parse, Parser, TransportPayload};
 use crate::socket::DisconnectReason;
 use crate::{
     errors::Error,
@@ -349,7 +349,8 @@ impl<A: Adapter> std::fmt::Debug for Client<A> {
     }
 }
 
-#[cfg(socketioxide_test)]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 impl<A: Adapter> Client<A> {
     pub async fn new_dummy_sock(
         self: Arc<Self>,
@@ -387,7 +388,7 @@ impl<A: Adapter> Client<A> {
                 }
             }
         });
-        let (p, _) = CommonParser::default().serialize(Packet {
+        let (p, _) = parser::CommonParser::default().serialize(Packet {
             ns: ns.into(),
             inner: PacketData::Connect(Some(serde_json::to_value(&auth).unwrap())),
         });
diff --git a/socketioxide/src/io.rs b/socketioxide/src/io.rs
index d133f801..3250d17c 100644
--- a/socketioxide/src/io.rs
+++ b/socketioxide/src/io.rs
@@ -905,7 +905,8 @@ impl<A: Adapter> From<Arc<Client<A>>> for SocketIo<A> {
     }
 }
 
-#[cfg(any(test, socketioxide_test))]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 impl<A: Adapter> SocketIo<A> {
     /// Create a dummy socket for testing purpose with a
     /// receiver to get the packets sent to the client
diff --git a/socketioxide/src/ns.rs b/socketioxide/src/ns.rs
index 365588fa..c4c4fec8 100644
--- a/socketioxide/src/ns.rs
+++ b/socketioxide/src/ns.rs
@@ -183,7 +183,8 @@ impl<A: Adapter> Namespace<A> {
     }
 }
 
-#[cfg(any(test, socketioxide_test))]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 impl<A: Adapter> Namespace<A> {
     pub fn new_dummy<const S: usize>(sockets: [Sid; S]) -> Arc<Self> {
         let ns = Namespace::new("/".into(), || {});
diff --git a/socketioxide/src/socket.rs b/socketioxide/src/socket.rs
index ee6ecbe9..311b4d21 100644
--- a/socketioxide/src/socket.rs
+++ b/socketioxide/src/socket.rs
@@ -820,7 +820,8 @@ impl<A: Adapter> PartialEq for Socket<A> {
     }
 }
 
-#[cfg(any(test, socketioxide_test))]
+#[doc(hidden)]
+#[cfg(feature = "__test_harness")]
 impl<A: Adapter> Socket<A> {
     /// Creates a dummy socket for testing purposes
     pub fn new_dummy(sid: Sid, ns: Arc<Namespace<A>>) -> Socket<A> {