diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index cbe5aee..7a27779 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,8 +2,6 @@ name: test
 
 on:
   push:
-  pull_request:
-    types: [synchronize, review_requested]
 
 env:
   CARGO_TERM_COLOR: always
@@ -12,7 +10,53 @@ permissions:
   contents: read
 
 jobs:
-  build:
+  test-unit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: arduino/setup-protoc@v3
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo test --verbose
+
+  test-beta:
+    runs-on: ubuntu-latest
+    needs: [test-unit]
+    strategy:
+      fail-fast: false
+      matrix:
+        toolchain:
+          - beta
+          - nightly
+    steps:
+      - uses: arduino/setup-protoc@v3
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.toolchain }}
+      - run: cargo test --verbose
+
+  test-functional:
+    needs: [test-unit]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: arduino/setup-protoc@v3
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo test --verbose --features=test-e2e
+        env:
+          CODEMP_TEST_USERNAME_ALICE: ${{ secrets.CODEMP_TEST_USERNAME_ALICE }}
+          CODEMP_TEST_PASSWORD_ALICE: ${{ secrets.CODEMP_TEST_PASSWORD_ALICE }}
+          CODEMP_TEST_USERNAME_BOB: ${{ secrets.CODEMP_TEST_USERNAME_BOB }}
+          CODEMP_TEST_PASSWORD_BOB: ${{ secrets.CODEMP_TEST_PASSWORD_BOB }}
+
+  test-build:
+    needs: [test-functional]
     runs-on: ${{ matrix.runner }}
     strategy:
       fail-fast: false
@@ -26,34 +70,10 @@ jobs:
           - js
           - py
           - luajit
-          - lua54
-        toolchain:
-          - stable
-          - beta
     steps:
       - uses: arduino/setup-protoc@v3
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ matrix.toolchain }}
+      - uses: dtolnay/rust-toolchain@stable
       - run: cargo build --release --verbose --features=${{ matrix.features }}
-
-  test:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        toolchain:
-          - stable
-          - beta
-    steps:
-      - uses: arduino/setup-protoc@v3
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ matrix.toolchain }}
-      - run: cargo test --verbose
diff --git a/Cargo.toml b/Cargo.toml
index 4ec0fa1..f5a1f49 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -68,6 +68,8 @@ default = []
 # extra
 async-trait = ["dep:async-trait"]
 serialize = ["dep:serde", "uuid/serde"]
+# special tests which require more setup
+test-e2e = []
 # ffi
 java = ["lazy_static", "jni", "tracing-subscriber", "jni-toolbox"]
 js = ["napi-build", "tracing-subscriber", "napi", "napi-derive"]
diff --git a/dist/java/src/mp/code/Client.java b/dist/java/src/mp/code/Client.java
index 465d10a..113aa65 100644
--- a/dist/java/src/mp/code/Client.java
+++ b/dist/java/src/mp/code/Client.java
@@ -128,7 +128,8 @@ public final class Client {
 	/**
 	 * Leaves a workspace.
 	 * @param workspaceId the id of the workspaces to leave
-	 * @return true if it succeeded (usually fails if the workspace wasn't active)
+	 * @return true if it succeeded or wasn't in the workspace; false if there are still
+	 *         leftover references around
 	 */
 	public boolean leaveWorkspace(String workspaceId) {
 		return leave_workspace(this.ptr, workspaceId);
diff --git a/src/lib.rs b/src/lib.rs
index 3179b7f..7177d8f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -125,6 +125,9 @@ pub mod ext;
 /// language-specific ffi "glue"
 pub mod ffi;
 
+#[cfg(any(feature = "test-e2e", test))]
+pub mod tests;
+
 /// internal network services and interceptors
 pub(crate) mod network;
 
diff --git a/src/tests/client.rs b/src/tests/client.rs
new file mode 100644
index 0000000..dcd4dc0
--- /dev/null
+++ b/src/tests/client.rs
@@ -0,0 +1,369 @@
+use super::{
+	assert_or_err,
+	fixtures::{ClientFixture, ScopedFixture, WorkspaceFixture},
+};
+use crate::api::{AsyncReceiver, AsyncSender};
+
+#[tokio::test]
+async fn test_workspace_creation_and_deletion() {
+	super::fixture! {
+		ClientFixture::of("alice") => |client| {
+			let workspace_name = uuid::Uuid::new_v4().to_string();
+
+			client.create_workspace(&workspace_name).await?;
+
+			// we can't error, so we return empty vec which will be interpreted as err
+			let workspace_list_before = client.fetch_owned_workspaces().await.unwrap_or_default();
+
+			let res = client.delete_workspace(&workspace_name).await;
+
+			// we can and should err here, because empty vec will be counted as success!
+			let workspace_list_after = client.fetch_owned_workspaces().await?;
+
+			assert_or_err!(workspace_list_before.contains(&workspace_name));
+			res?;
+			assert_or_err!(workspace_list_after.contains(&workspace_name) == false);
+
+			Ok(())
+		}
+	};
+}
+
+#[tokio::test]
+async fn test_attach_and_leave_workspace() {
+	super::fixture! {
+		ClientFixture::of("alice") => |client| {
+			let workspace_name = uuid::Uuid::new_v4().to_string();
+
+			client.create_workspace(&workspace_name).await?;
+
+			// leaving a workspace you are not attached to, returns true
+			let leave_workspace_before = client.leave_workspace(&workspace_name);
+
+			let attach_workspace_that_exists = match client.attach_workspace(&workspace_name).await {
+				Ok(_) => true,
+				Err(e) => {
+					eprintln!("error attaching to workspace: {e}");
+					false
+				},
+			};
+
+			// leaving a workspace you are attached to, returns true
+			// when there is only one reference to it.
+			let leave_workspace_after = client.leave_workspace(&workspace_name);
+
+			let _ = client.delete_workspace(&workspace_name).await;
+
+			assert_or_err!(leave_workspace_before, "leaving a workspace you are not attached to returned false, should return true.");
+			assert_or_err!(attach_workspace_that_exists, "attaching a workspace that exists failed with error");
+			assert_or_err!(leave_workspace_after, "leaving a workspace with a single reference returned false.");
+
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_invite_user_to_workspace() {
+	let client_alice = ClientFixture::of("alice")
+		.setup()
+		.await
+		.expect("failed setting up alice's client");
+	let client_bob = ClientFixture::of("bob")
+		.setup()
+		.await
+		.expect("failed setting up bob's client");
+	let ws_name = uuid::Uuid::new_v4().to_string();
+
+	// after this we can't just fail anymore: we need to cleanup, so store errs
+	client_alice
+		.create_workspace(&ws_name)
+		.await
+		.expect("failed creating workspace");
+	let could_invite = client_alice
+		.invite_to_workspace(&ws_name, &client_bob.current_user().name)
+		.await;
+	let ws_list = client_bob
+		.fetch_joined_workspaces()
+		.await
+		.unwrap_or_default(); // can't fail, empty is err
+	let could_delete = client_alice.delete_workspace(&ws_name).await;
+
+	could_invite.expect("could not invite bob");
+	assert!(ws_list.contains(&ws_name));
+	could_delete.expect("could not delete workspace");
+}
+
+#[tokio::test]
+async fn test_workspace_lookup() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-lookup") => |client, workspace| {
+			assert_or_err!(client.get_workspace(&workspace.id()).is_some());
+			assert_or_err!(client.get_workspace(&uuid::Uuid::new_v4().to_string()).is_none());
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_leave_workspace_with_dangling_ref() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-dangling-ref") => |client, workspace| {
+			assert_or_err!(client.leave_workspace(&workspace.id()) == false);
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_lookup_after_leave() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-lookup-after-leave") => |client, workspace| {
+			client.leave_workspace(&workspace.id());
+			assert_or_err!(client.get_workspace(&workspace.id()).is_none());
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_attach_after_leave() {
+	super::fixture! {
+		ClientFixture::of("alice") => |client| {
+			let ws_name = uuid::Uuid::new_v4().to_string();
+			client.create_workspace(&ws_name).await?;
+
+			let could_attach = client.attach_workspace(&ws_name).await.is_ok();
+			let clean_leave = client.leave_workspace(&ws_name);
+			// TODO this is very server specific! disconnect may be instant or caught with next
+			// keepalive, let's arbitrarily say that after 20 seconds we should have been disconnected
+			tokio::time::sleep(std::time::Duration::from_secs(20)).await;
+			let could_attach_again = client.attach_workspace(&ws_name).await;
+			let could_delete = client.delete_workspace(&ws_name).await;
+
+			assert_or_err!(could_attach);
+			assert_or_err!(clean_leave);
+			could_attach_again?;
+			could_delete?;
+
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_active_workspaces() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-active-workspaces") => |client, workspace| {
+			assert_or_err!(client.active_workspaces().contains(&workspace.id()));
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_cant_create_same_workspace_more_than_once() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-create-multiple-times") => |client, workspace| {
+			assert_or_err!(client.create_workspace(workspace.id()).await.is_err(), "created same workspace twice");
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_attaching_to_non_existing_is_error() {
+	super::fixture! {
+		ClientFixture::of("alice") => |client| {
+			let workspace_name = uuid::Uuid::new_v4().to_string();
+
+			// we don't create any workspace.
+			// client.create_workspace(workspace_name).await?;
+			assert_or_err!(client.attach_workspace(&workspace_name).await.is_err());
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_deleting_workspace_twice_is_an_error() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-delete-twice") => |client, workspace| {
+			let workspace_name = workspace.id();
+
+			client.delete_workspace(&workspace_name).await?;
+			assert_or_err!(client.delete_workspace(&workspace_name).await.is_err());
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_cannot_invite_self() {
+	super::fixture! {
+		WorkspaceFixture::one("alice", "test-invite-self") => |client, workspace| {
+			assert_or_err!(client.invite_to_workspace(workspace.id(), &client.current_user().name).await.is_err());
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn test_cannot_invite_to_nonexisting() {
+	super::fixture! {
+		WorkspaceFixture::two("alice", "bob", "test-invite-self") => |client, _ws, client_bob, _workspace_bob| {
+			assert_or_err!(client.invite_to_workspace(uuid::Uuid::new_v4().to_string(), &client_bob.current_user().name).await.is_err());
+			Ok(())
+		}
+	}
+}
+
+#[tokio::test]
+async fn cannot_delete_others_workspaces() {
+	WorkspaceFixture::two("alice", "bob", "test-cannot-delete-others-workspaces")
+		.with(|(_, ws_alice, client_bob, _)| {
+			let ws_alice = ws_alice.clone();
+			let client_bob = client_bob.clone();
+			async move {
+				assert_or_err!(
+					client_bob.delete_workspace(&ws_alice.id()).await.is_err(),
+					"bob was allowed to delete a workspace he didn't own!"
+				);
+				Ok(())
+			}
+		})
+		.await
+}
+
+#[tokio::test]
+async fn test_buffer_search() {
+	WorkspaceFixture::one("alice", "test-buffer-search")
+		.with(|(_, workspace_alice)| {
+			let buffer_name = uuid::Uuid::new_v4().to_string();
+			let workspace_alice = workspace_alice.clone();
+
+			async move {
+				workspace_alice.create_buffer(&buffer_name).await?;
+				assert_or_err!(!workspace_alice
+					.search_buffers(Some(&buffer_name[0..4]))
+					.is_empty());
+				assert_or_err!(workspace_alice.search_buffers(Some("_")).is_empty());
+				workspace_alice.delete_buffer(&buffer_name).await?;
+				Ok(())
+			}
+		})
+		.await;
+}
+
+#[tokio::test]
+async fn test_send_operation() {
+	WorkspaceFixture::two("alice", "bob", "test-send-operation")
+		.with(|(_, workspace_alice, _, workspace_bob)| {
+			let buffer_name = uuid::Uuid::new_v4().to_string();
+			let workspace_alice = workspace_alice.clone();
+			let workspace_bob = workspace_bob.clone();
+
+			async move {
+				workspace_alice.create_buffer(&buffer_name).await?;
+				let alice = workspace_alice.attach_buffer(&buffer_name).await?;
+				let bob = workspace_bob.attach_buffer(&buffer_name).await?;
+
+				alice.send(crate::api::TextChange {
+					start_idx: 0,
+					end_idx: 0,
+					content: "hello world".to_string(),
+				})?;
+
+				let result = bob.recv().await?;
+				assert_or_err!(result.change.start_idx == 0);
+				assert_or_err!(result.change.end_idx == 0);
+				assert_or_err!(result.change.content == "hello world");
+
+				Ok(())
+			}
+		})
+		.await;
+}
+
+#[tokio::test]
+async fn test_content_converges() {
+	WorkspaceFixture::two("alice", "bob", "test-content-converges")
+		.with(|(_, workspace_alice, _, workspace_bob)| {
+			let buffer_name = uuid::Uuid::new_v4().to_string();
+			let workspace_alice = workspace_alice.clone();
+			let workspace_bob = workspace_bob.clone();
+
+			async move {
+				workspace_alice.create_buffer(&buffer_name).await?;
+				let alice = workspace_alice.attach_buffer(&buffer_name).await?;
+				let bob = workspace_bob.attach_buffer(&buffer_name).await?;
+
+				let mut join_set = tokio::task::JoinSet::new();
+
+				let _alice = alice.clone();
+				join_set.spawn(async move {
+					for i in 0..10 {
+						_alice.content().await?;
+						_alice.send(crate::api::TextChange {
+							start_idx: 7 * i,
+							end_idx: 7 * i,
+							content: format!("alice{i} "), // TODO generate a random string instead!!
+						})?;
+						tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+					}
+					Ok::<(), crate::errors::ControllerError>(())
+				});
+
+				let _bob = bob.clone();
+				join_set.spawn(async move {
+					for i in 0..10 {
+						_bob.content().await?;
+						_bob.send(crate::api::TextChange {
+							start_idx: 5 * i,
+							end_idx: 5 * i,
+							content: format!("bob{i} "), // TODO generate a random string instead!!
+						})?;
+						tokio::time::sleep(std::time::Duration::from_millis(100)).await;
+					}
+					Ok::<(), crate::errors::ControllerError>(())
+				});
+
+				while let Some(x) = join_set.join_next().await {
+					x??;
+				}
+
+				// test runners may be slow, give 1s to catch up, just in case
+				tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+
+				// TODO is there a nicer way to make sure we received all changes?
+				for i in 0..20 {
+					tokio::time::sleep(std::time::Duration::from_millis(200)).await;
+					match bob.try_recv().await? {
+						Some(change) => bob.ack(change.version),
+						None => break,
+					}
+					eprintln!("bob more to recv at attempt #{i}");
+				}
+
+				for i in 0..20 {
+					tokio::time::sleep(std::time::Duration::from_millis(200)).await;
+					match alice.try_recv().await? {
+						Some(change) => alice.ack(change.version),
+						None => break,
+					}
+					eprintln!("alice more to recv at attempt #{i}");
+				}
+
+				let alice_content = alice.content().await?;
+				let bob_content = bob.content().await?;
+
+				eprintln!("alice: {alice_content}");
+				eprintln!("bob  : {bob_content}");
+
+				assert_or_err!(alice_content == bob_content);
+
+				Ok(())
+			}
+		})
+		.await;
+}
diff --git a/src/tests/fixtures.rs b/src/tests/fixtures.rs
new file mode 100644
index 0000000..b52712c
--- /dev/null
+++ b/src/tests/fixtures.rs
@@ -0,0 +1,291 @@
+use std::{error::Error, future::Future};
+
+#[allow(async_fn_in_trait)]
+pub trait ScopedFixture<T: Sized> {
+	async fn setup(&mut self) -> Result<T, Box<dyn Error>>;
+
+	async fn cleanup(&mut self, resource: Option<T>) {
+		drop(resource)
+	}
+
+	async fn inner_with<F>(mut self, cb: impl FnOnce(&mut T) -> F) -> Result<(), Box<dyn Error>>
+	where
+		Self: Sized,
+		F: Future<Output = Result<(), Box<dyn Error>>>,
+	{
+		match self.setup().await {
+			Ok(mut t) => {
+				let res = cb(&mut t).await;
+				self.cleanup(Some(t)).await;
+				res
+			}
+			Err(e) => {
+				self.cleanup(None).await;
+				Err(e)
+			}
+		}
+	}
+
+	async fn with<F>(self, cb: impl FnOnce(&mut T) -> F)
+	where
+		Self: Sized,
+		F: Future<Output = Result<(), Box<dyn std::error::Error>>>,
+	{
+		if let Err(e) = self.inner_with(cb).await {
+			panic!("{e}");
+		}
+	}
+}
+
+pub struct ClientFixture {
+	name: String,
+	username: Option<String>,
+	password: Option<String>,
+}
+
+impl ClientFixture {
+	pub fn of(name: &str) -> Self {
+		Self {
+			name: name.to_string(),
+			username: None,
+			password: None,
+		}
+	}
+}
+
+impl ScopedFixture<crate::Client> for ClientFixture {
+	async fn setup(&mut self) -> Result<crate::Client, Box<dyn Error>> {
+		let upper = self.name.to_uppercase();
+		let username = self.username.clone().unwrap_or_else(|| {
+			std::env::var(format!("CODEMP_TEST_USERNAME_{upper}")).unwrap_or_default()
+		});
+		let password = self.password.clone().unwrap_or_else(|| {
+			std::env::var(format!("CODEMP_TEST_PASSWORD_{upper}")).unwrap_or_default()
+		});
+		let client = crate::Client::connect(crate::api::Config {
+			username,
+			password,
+			tls: Some(false),
+			..Default::default()
+		})
+		.await?;
+
+		Ok(client)
+	}
+}
+
+pub struct WorkspaceFixture {
+	user: String,
+	invitee: Option<String>,
+	workspace: String,
+}
+
+impl WorkspaceFixture {
+	pub fn of(user: &str, invitee: &str, workspace: &str) -> Self {
+		Self {
+			user: user.to_string(),
+			invitee: Some(invitee.to_string()),
+			workspace: workspace.to_string(),
+		}
+	}
+
+	pub fn one(user: &str, ws: &str) -> Self {
+		Self {
+			user: user.to_string(),
+			invitee: None,
+			workspace: format!("{ws}-{}", uuid::Uuid::new_v4()),
+		}
+	}
+
+	pub fn two(user: &str, invite: &str, ws: &str) -> Self {
+		Self {
+			user: user.to_string(),
+			invitee: Some(invite.to_string()),
+			workspace: format!("{ws}-{}", uuid::Uuid::new_v4()),
+		}
+	}
+}
+
+impl ScopedFixture<(crate::Client, crate::Workspace)> for WorkspaceFixture {
+	async fn setup(&mut self) -> Result<(crate::Client, crate::Workspace), Box<dyn Error>> {
+		let client = ClientFixture::of(&self.user).setup().await?;
+		client.create_workspace(&self.workspace).await?;
+		let workspace = client.attach_workspace(&self.workspace).await?;
+		Ok((client, workspace))
+	}
+
+	async fn cleanup(&mut self, resource: Option<(crate::Client, crate::Workspace)>) {
+		if let Some((client, _workspace)) = resource {
+			client.leave_workspace(&self.workspace);
+			if let Err(e) = client.delete_workspace(&self.workspace).await {
+				eprintln!("could not delete workspace: {e}");
+			}
+		}
+	}
+}
+
+impl
+	ScopedFixture<(
+		crate::Client,
+		crate::Workspace,
+		crate::Client,
+		crate::Workspace,
+	)> for WorkspaceFixture
+{
+	async fn setup(
+		&mut self,
+	) -> Result<
+		(
+			crate::Client,
+			crate::Workspace,
+			crate::Client,
+			crate::Workspace,
+		),
+		Box<dyn Error>,
+	> {
+		let client = ClientFixture::of(&self.user).setup().await?;
+		let invitee_client = ClientFixture::of(
+			&self
+				.invitee
+				.clone()
+				.unwrap_or(uuid::Uuid::new_v4().to_string()),
+		)
+		.setup()
+		.await?;
+		client.create_workspace(&self.workspace).await?;
+		client
+			.invite_to_workspace(&self.workspace, invitee_client.current_user().name.clone())
+			.await?;
+		let workspace = client.attach_workspace(&self.workspace).await?;
+		let invitee_workspace = invitee_client.attach_workspace(&self.workspace).await?;
+		Ok((client, workspace, invitee_client, invitee_workspace))
+	}
+
+	async fn cleanup(
+		&mut self,
+		resource: Option<(
+			crate::Client,
+			crate::Workspace,
+			crate::Client,
+			crate::Workspace,
+		)>,
+	) {
+		if let Some((client, _, _, _)) = resource {
+			client.leave_workspace(&self.workspace);
+			if let Err(e) = client.delete_workspace(&self.workspace).await {
+				eprintln!("could not delete workspace: {e}");
+			}
+		}
+	}
+}
+
+pub struct BufferFixture {
+	user: String,
+	invitee: Option<String>,
+	workspace: String,
+	buffer: String,
+}
+
+impl BufferFixture {
+	pub fn of(user: &str, invitee: &str, workspace: &str, buffer: &str) -> Self {
+		Self {
+			user: user.to_string(),
+			invitee: Some(invitee.to_string()),
+			workspace: workspace.to_string(),
+			buffer: buffer.to_string(),
+		}
+	}
+
+	pub fn one(user: &str, ws: &str, buf: &str) -> Self {
+		Self {
+			user: user.to_string(),
+			invitee: None,
+			workspace: format!("{ws}-{}", uuid::Uuid::new_v4()),
+			buffer: buf.to_string(),
+		}
+	}
+
+	pub fn two(user: &str, invite: &str, ws: &str, buf: &str) -> Self {
+		Self {
+			user: user.to_string(),
+			invitee: Some(invite.to_string()),
+			workspace: format!("{ws}-{}", uuid::Uuid::new_v4()),
+			buffer: buf.to_string(),
+		}
+	}
+}
+
+impl
+	ScopedFixture<(
+		crate::Client,
+		crate::Workspace,
+		crate::buffer::Controller,
+		crate::Client,
+		crate::Workspace,
+		crate::buffer::Controller,
+	)> for BufferFixture
+{
+	async fn setup(
+		&mut self,
+	) -> Result<
+		(
+			crate::Client,
+			crate::Workspace,
+			crate::buffer::Controller,
+			crate::Client,
+			crate::Workspace,
+			crate::buffer::Controller,
+		),
+		Box<dyn Error>,
+	> {
+		let client = ClientFixture::of(&self.user).setup().await?;
+		let invitee_client = ClientFixture::of(
+			&self
+				.invitee
+				.clone()
+				.unwrap_or(uuid::Uuid::new_v4().to_string()),
+		)
+		.setup()
+		.await?;
+		client.create_workspace(&self.workspace).await?;
+		client
+			.invite_to_workspace(&self.workspace, invitee_client.current_user().name.clone())
+			.await?;
+
+		let workspace = client.attach_workspace(&self.workspace).await?;
+		workspace.create_buffer(&self.buffer).await?;
+		let buffer = workspace.attach_buffer(&self.buffer).await?;
+
+		let invitee_workspace = invitee_client.attach_workspace(&self.workspace).await?;
+		let invitee_buffer = invitee_workspace.attach_buffer(&self.buffer).await?;
+
+		Ok((
+			client,
+			workspace,
+			buffer,
+			invitee_client,
+			invitee_workspace,
+			invitee_buffer,
+		))
+	}
+
+	async fn cleanup(
+		&mut self,
+		resource: Option<(
+			crate::Client,
+			crate::Workspace,
+			crate::buffer::Controller,
+			crate::Client,
+			crate::Workspace,
+			crate::buffer::Controller,
+		)>,
+	) {
+		if let Some((client, _, _, _, _, _)) = resource {
+			// buffer deletion is implied in workspace deletion
+			client.leave_workspace(&self.workspace);
+			if let Err(e) = client.delete_workspace(&self.workspace).await {
+				eprintln!("could not delete workspace: {e}");
+			}
+		}
+	}
+}
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
new file mode 100644
index 0000000..6349652
--- /dev/null
+++ b/src/tests/mod.rs
@@ -0,0 +1,100 @@
+#[cfg(all(test, feature = "test-e2e"))]
+mod client;
+
+#[cfg(all(test, feature = "test-e2e"))]
+mod server;
+
+pub mod fixtures;
+use crate::errors::{ConnectionError, RemoteError};
+
+#[derive(Debug)]
+pub struct AssertionError(String);
+
+impl AssertionError {
+	pub fn new(msg: &str) -> Self {
+		Self(msg.to_string())
+	}
+}
+
+impl std::fmt::Display for AssertionError {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "{}", self.0)
+	}
+}
+
+impl std::error::Error for AssertionError {}
+
+impl From<ConnectionError> for AssertionError {
+	fn from(value: ConnectionError) -> Self {
+		match value {
+			ConnectionError::Transport(error) => AssertionError::new(&format!(
+				"Connection::Transport error during setup of a test: {}",
+				error,
+			)),
+			ConnectionError::Remote(remote_error) => AssertionError::new(&format!(
+				"Connection::Remote error during setup of a test: {}",
+				remote_error,
+			)),
+		}
+	}
+}
+
+impl From<RemoteError> for AssertionError {
+	fn from(value: RemoteError) -> Self {
+		AssertionError::new(&format!("Remote error during setup of a test: {}", value,))
+	}
+}
+
+#[macro_export]
+macro_rules! assert_or_err {
+	($s:expr) => {
+		#[allow(clippy::bool_comparison)]
+		if !$s {
+			return Err($crate::tests::AssertionError::new(&format!(
+				"assertion failed at line {}: {}",
+				std::line!(),
+				stringify!($s)
+			))
+			.into());
+		}
+	};
+	($s:expr, $msg:literal) => {
+		#[allow(clippy::bool_comparison)]
+		if !$s {
+			return Err($crate::tests::AssertionError::new(&format!(
+				"{} (line {})",
+				$msg,
+				std::line!(),
+			))
+			.into());
+		}
+	};
+	($s:expr, raw $msg:literal) => {
+		#[allow(clippy::bool_comparison)]
+		if !$s {
+			return Err($crate::tests::AssertionError::new($msg).into());
+		}
+	};
+}
+
+pub use assert_or_err;
+
+#[macro_export]
+macro_rules! fixture {
+	($fixture:expr => | $($arg:ident),* | $body:expr) => {
+		#[allow(unused_parens)]
+		$fixture
+			.with(|($($arg),*)| {
+				$(
+					let $arg = $arg.clone();
+				)*
+
+				async move {
+					$body
+				}
+			})
+			.await;
+	};
+}
+
+pub use fixture;
diff --git a/src/tests/server.rs b/src/tests/server.rs
new file mode 100644
index 0000000..ebcf4ce
--- /dev/null
+++ b/src/tests/server.rs
@@ -0,0 +1,92 @@
+use super::{
+	assert_or_err,
+	fixtures::{ClientFixture, ScopedFixture, WorkspaceFixture},
+};
+
+#[tokio::test]
+async fn test_buffer_create() {
+	WorkspaceFixture::one("alice", "test-buffer-create")
+		.with(|(_, workspace_alice)| {
+			let buffer_name = uuid::Uuid::new_v4().to_string();
+			let workspace_alice = workspace_alice.clone();
+
+			async move {
+				workspace_alice.create_buffer(&buffer_name).await?;
+				assert_or_err!(vec![buffer_name.clone()] == workspace_alice.fetch_buffers().await?);
+				workspace_alice.delete_buffer(&buffer_name).await?;
+
+				Ok(())
+			}
+		})
+		.await;
+}
+
+#[tokio::test]
+async fn test_cant_create_buffer_twice() {
+	WorkspaceFixture::one("alice", "test-cant-create-buffer-twice")
+		.with(|(_, ws)| {
+			let ws = ws.clone();
+			async move {
+				ws.create_buffer("cacca").await?;
+				assert!(
+					ws.create_buffer("cacca").await.is_err(),
+					"alice could create again the same buffer"
+				);
+				Ok(())
+			}
+		})
+		.await;
+}
+
+#[tokio::test]
+#[ignore] // TODO reference server has no concept of buffer ownership yet!
+async fn cannot_delete_others_buffers() {
+	WorkspaceFixture::two("alice", "bob", "test-cannot-delete-others-buffers")
+		.with(|(_, workspace_alice, _, workspace_bob)| {
+			let buffer_name = uuid::Uuid::new_v4().to_string();
+			let workspace_alice = workspace_alice.clone();
+			let workspace_bob = workspace_bob.clone();
+
+			async move {
+				workspace_alice.create_buffer(&buffer_name).await?;
+				assert_or_err!(workspace_bob.delete_buffer(&buffer_name).await.is_err());
+				Ok(())
+			}
+		})
+		.await;
+}
+
+#[tokio::test] // TODO split down this test in smaller checks
+async fn test_workspace_interactions() {
+	if let Err(e) = async {
+		let client_alice = ClientFixture::of("alice").setup().await?;
+		let client_bob = ClientFixture::of("bob").setup().await?;
+		let workspace_name = format!("test-workspace-interactions-{}", uuid::Uuid::new_v4());
+
+		client_alice.create_workspace(&workspace_name).await?;
+		let owned_workspaces = client_alice.fetch_owned_workspaces().await?;
+		assert_or_err!(owned_workspaces.contains(&workspace_name));
+		client_alice.attach_workspace(&workspace_name).await?;
+		assert_or_err!(vec![workspace_name.clone()] == client_alice.active_workspaces());
+
+		client_alice
+			.invite_to_workspace(&workspace_name, &client_bob.current_user().name)
+			.await?;
+		client_bob.attach_workspace(&workspace_name).await?;
+		assert_or_err!(client_bob
+			.fetch_joined_workspaces()
+			.await?
+			.contains(&workspace_name));
+
+		assert_or_err!(client_bob.leave_workspace(&workspace_name));
+		assert_or_err!(client_alice.leave_workspace(&workspace_name));
+
+		client_alice.delete_workspace(&workspace_name).await?;
+
+		Ok::<(), Box<dyn std::error::Error>>(())
+	}
+	.await
+	{
+		panic!("{e}");
+	}
+}
diff --git a/src/workspace.rs b/src/workspace.rs
index f8054fc..787166a 100644
--- a/src/workspace.rs
+++ b/src/workspace.rs
@@ -185,10 +185,10 @@ impl Workspace {
 	///
 	/// This will stop and drop its [`buffer::Controller`].
 	///
-	/// Returns `true` if connectly dropped or wasn't present, `false` if dropped but wasn't last ref
-	///
-	/// If this method returns `false` you have a dangling ref, maybe just waiting for garbage
-	/// collection or maybe preventing the controller from being dropped completely
+	/// Returns `true` if it was connectly dropped or wasn't present, `false` if it was dropped but
+	/// wasn't the last existing reference to it. If this method returns `false` it means you have
+	/// a dangling reference somewhere. It may just be waiting for garbage collection, but as long
+	/// as it exists, it will prevent the controller from being completely dropped.
 	#[allow(clippy::redundant_pattern_matching)] // all cases are clearer this way
 	pub fn detach_buffer(&self, path: &str) -> bool {
 		match self.0.buffers.remove(path) {