From 420029b6d1cdee55445250fcfb2983bd9da41df6 Mon Sep 17 00:00:00 2001
From: Stepan Koltsov <stepan.koltsov@gmail.com>
Date: Fri, 24 Nov 2023 18:31:36 +0000
Subject: [PATCH] bevy_mocks crate

---
 crates/bevy_ecs/Cargo.toml             |  2 ++
 crates/bevy_ecs/src/schedule/config.rs | 19 +++++++------------
 crates/bevy_mocks/Cargo.toml           | 17 +++++++++++++++++
 crates/bevy_mocks/src/app.rs           |  7 +++++++
 crates/bevy_mocks/src/app_schedule.rs  |  1 +
 crates/bevy_mocks/src/input.rs         |  1 +
 crates/bevy_mocks/src/keyboard.rs      |  3 +++
 crates/bevy_mocks/src/lib.rs           |  8 ++++++++
 crates/bevy_mocks/src/schedule.rs      |  7 +++++++
 crates/bevy_mocks/src/system.rs        |  1 +
 10 files changed, 54 insertions(+), 12 deletions(-)
 create mode 100644 crates/bevy_mocks/Cargo.toml
 create mode 100644 crates/bevy_mocks/src/app.rs
 create mode 100644 crates/bevy_mocks/src/app_schedule.rs
 create mode 100644 crates/bevy_mocks/src/input.rs
 create mode 100644 crates/bevy_mocks/src/keyboard.rs
 create mode 100644 crates/bevy_mocks/src/lib.rs
 create mode 100644 crates/bevy_mocks/src/schedule.rs
 create mode 100644 crates/bevy_mocks/src/system.rs

diff --git a/crates/bevy_ecs/Cargo.toml b/crates/bevy_ecs/Cargo.toml
index 3231e7b4101ff..bd82f9aa9fe11 100644
--- a/crates/bevy_ecs/Cargo.toml
+++ b/crates/bevy_ecs/Cargo.toml
@@ -31,6 +31,8 @@ serde = "1"
 thiserror = "1.0"
 
 [dev-dependencies]
+bevy_mocks = { path = "../bevy_mocks", version = "0.12.0" }
+
 rand = "0.8"
 
 [[example]]
diff --git a/crates/bevy_ecs/src/schedule/config.rs b/crates/bevy_ecs/src/schedule/config.rs
index 3ce86039ad0f8..19f5faf129a3b 100644
--- a/crates/bevy_ecs/src/schedule/config.rs
+++ b/crates/bevy_ecs/src/schedule/config.rs
@@ -214,19 +214,14 @@ impl<T> NodeConfigs<T> {
 /// # Examples
 ///
 /// ```
-/// # use bevy_ecs::schedule::IntoSystemConfigs;
-/// # struct AppMock;
-/// # struct Update;
-/// # impl AppMock {
-/// #     pub fn add_systems<M>(
-/// #         &mut self,
-/// #         schedule: Update,
-/// #         systems: impl IntoSystemConfigs<M>,
-/// #    ) -> &mut Self { self }
-/// # }
-/// # let mut app = AppMock;
+/// # use bevy_mocks::app_schedule::Update;
+/// # use bevy_mocks::input::Input;
+/// # use bevy_mocks::keyboard::KeyCode;
+/// # use bevy_mocks::schedule::IntoSystemConfigs;
+/// # use bevy_mocks::system::Res;
+/// # let mut app = bevy_mocks::app::App;
 ///
-/// fn handle_input() {}
+/// fn handle_input(keys: Res<Input<KeyCode>>) {}
 ///
 /// fn update_camera() {}
 /// fn update_character() {}
diff --git a/crates/bevy_mocks/Cargo.toml b/crates/bevy_mocks/Cargo.toml
new file mode 100644
index 0000000000000..9121847fd61a1
--- /dev/null
+++ b/crates/bevy_mocks/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+name = "bevy_mocks"
+version = "0.12.0"
+edition = "2021"
+description = "API mocks for Bevy for doctests"
+homepage = "https://bevyengine.org"
+repository = "https://github.com/bevyengine/bevy"
+license = "MIT OR Apache-2.0"
+keywords = ["bevy"]
+
+[dependencies]
+# We could add dependency crates like `bevy_ecs` here, it works locally, but according to this,
+# such crates cannot be published:
+# https://github.com/rust-lang/cargo/issues/4242
+
+[lints]
+workspace = true
diff --git a/crates/bevy_mocks/src/app.rs b/crates/bevy_mocks/src/app.rs
new file mode 100644
index 0000000000000..3505bba8f54be
--- /dev/null
+++ b/crates/bevy_mocks/src/app.rs
@@ -0,0 +1,7 @@
+pub struct App;
+
+impl App {
+    pub fn add_systems<C, S>(&mut self, _schedule: C, _systems: S) -> &mut Self {
+        self
+    }
+}
diff --git a/crates/bevy_mocks/src/app_schedule.rs b/crates/bevy_mocks/src/app_schedule.rs
new file mode 100644
index 0000000000000..01be2275bf19a
--- /dev/null
+++ b/crates/bevy_mocks/src/app_schedule.rs
@@ -0,0 +1 @@
+pub struct Update;
diff --git a/crates/bevy_mocks/src/input.rs b/crates/bevy_mocks/src/input.rs
new file mode 100644
index 0000000000000..14e8622122f44
--- /dev/null
+++ b/crates/bevy_mocks/src/input.rs
@@ -0,0 +1 @@
+pub struct Input<T>(T);
diff --git a/crates/bevy_mocks/src/keyboard.rs b/crates/bevy_mocks/src/keyboard.rs
new file mode 100644
index 0000000000000..b3fd47159febd
--- /dev/null
+++ b/crates/bevy_mocks/src/keyboard.rs
@@ -0,0 +1,3 @@
+pub enum KeyCode {
+    A,
+}
diff --git a/crates/bevy_mocks/src/lib.rs b/crates/bevy_mocks/src/lib.rs
new file mode 100644
index 0000000000000..cc6395ae1074b
--- /dev/null
+++ b/crates/bevy_mocks/src/lib.rs
@@ -0,0 +1,8 @@
+//! API mocks for Bevy compile-only doctests as illustrations.
+
+pub mod app;
+pub mod app_schedule;
+pub mod input;
+pub mod keyboard;
+pub mod schedule;
+pub mod system;
diff --git a/crates/bevy_mocks/src/schedule.rs b/crates/bevy_mocks/src/schedule.rs
new file mode 100644
index 0000000000000..d708e326a4f45
--- /dev/null
+++ b/crates/bevy_mocks/src/schedule.rs
@@ -0,0 +1,7 @@
+pub trait IntoSystemConfigs: Sized {
+    fn after<T>(self, _other: T) -> Self {
+        self
+    }
+}
+
+impl<T> IntoSystemConfigs for T {}
diff --git a/crates/bevy_mocks/src/system.rs b/crates/bevy_mocks/src/system.rs
new file mode 100644
index 0000000000000..8377fea00dbe6
--- /dev/null
+++ b/crates/bevy_mocks/src/system.rs
@@ -0,0 +1 @@
+pub struct Res<T>(T);