Merge branch 'master' of https://github.com/richelbilderbeek/bevy_tdd…

…_book

hello_world.md

@@ -1,60 +1,63 @@
 # Hello world
 
-This chapter is a minimal Bevy program.
+This chapter is about creating a minimal Bevy program that is completely tested.
 
-The minimal program will create a Bevy `App`
-and then run it ([main.rs](https://github.com/richelbilderbeek/bevy_tdd_book_hello_world/blob/master/src/main.rs)):
+## First test
 
-```rust
-use crate::app::create_app;
-mod app;
+Our first test is about creating a Bevy program.
+The Bevy class for this, is called [`App`](https://docs.rs/bevy/latest/bevy/app/struct.App.html).
+Hence, we call the function to create a Bevy program `create_app`.
 
-fn main() {
-    let mut app = create_app();
-    app.run();
+Our first trivial test will be if `create_app` does something, 
+i.e. it does not crash:
+
+```rust
+fn test_can_create_app() {
+    create_app();
 }
 ```
 
-The `main` function will not be used in automated testing,
-as it starts our game: starting the game
-will require that a user needs to do something to close it.
-Hence, the `main` function 'just' runs the `App`.
+This test will break the code, as the function `create_app` does not exist yet.
 
-The testing takes place in the `create_app` function.
-The first two lines of `main.rs` allow us to call the `create_app`
-function in the file [app.rs](https://github.com/richelbilderbeek/bevy_tdd_book_hello_world/blob/master/src/app.rs).
+## First fix
 
-Our first trivial test will be if `create_app` does something,
-i.e. it does not crash:
+Here is a possible implementation of `create_app`:
 
 ```rust
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_can_create_app() {
-        create_app();
-    }
+pub fn create_app() -> App {
+    App::new()
 }
 ```
 
-Writing this test will break the code, as the function `create_app`
-does not exist yet.
+Another option is to use `return App::new();` in the function body instead.
+This, however, does not follow the Rust style recommended by the `clippy`
+crate.
 
-Here is the `create_app` function definition that fixes all tests:
+## `main.rs`
 
-```rust
-use bevy::prelude::*;
+The `main` function will not be used in automated testing,
+as it starts our game: starting the game
+will require that a user needs to do something to close it.
+Hence, the `main` function 'just' runs the `App`.
 
-pub fn create_app() -> App {
-    return App::new();
+```rust
+fn main() {
+    let mut app = create_app();
+    app.add_plugins(DefaultPlugins);
+    app.run();
 }
 ```
 
+The `main` function does add the Bevy default plugins. 
+These plugins will add functionality to an `App`, such
+as creating a window.
+Due to this, our `App` that does nothing can be displayed:
+
+[An empty Bevy App](hello_world.md)
+
 ## Conclusion
 
-We can now create an `App`. It does nothing and displays nothing.
+We can now create an `App`. It does nothing.
 However, we do have tested everything (i.e. nothing) it does!
 
 Full code can be found at [https://github.com/richelbilderbeek/bevy_tdd_book_hello_world](https://github.com/richelbilderbeek/bevy_tdd_book_hello_world)

scripts/clone_all_chapters.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+#
+# Clone all chapters in folders next to this one.
+#
+# This means that after this script, you'll have a folder structure like:
+#
+#   ../bevy_tdd_book
+#   ../bevy_tdd_book_hello_world
+#   ../bevy_tdd_book_[other chapters]
+#
+# Usage:
+#
+#   ./scripts/clone_all_chapters.sh
+
+if [[ "$PWD" =~ scripts$ ]]; then
+    echo "FATAL ERROR."
+    echo "Please run the script from the project root. "
+    echo "Present working director: $PWD"
+    echo " "
+    echo "Tip: like this"
+    echo " "
+    echo "  ./scripts/clone_all_chapters.sh"
+    echo " "
+    exit 42
+fi
+
+# ls *.md | grep -v [A-Z] | grep -v "faq\\.md" 
+rscript scripts/clone_all_chapters_impl.R
+
+

scripts/clone_all_chapters_impl.R

@@ -0,0 +1,27 @@
+# Current working directory must end with bevy_tdd_book
+
+pwd <- getwd()
+
+if (!stringr::str_detect(pwd, "bevy_tdd_book$")) {
+  stop("Run this script in the 'bevy_tdd_book' folder")
+}
+
+
+all_md_files <- list.files(pattern = "md")
+md_files <- stringr::str_subset(all_md_files, "[A-Z]", negate = TRUE) 
+md_files <- stringr::str_subset(md_files, "faq.md", negate = TRUE) 
+md_files <- stringr::str_subset(md_files, "functions.md", negate = TRUE) 
+md_files
+
+chapter_names <- stringr::str_sub(md_files, end = -4)
+
+setwd("..")
+pwd <- getwd()
+
+testthat::expect_false(stringr::str_detect(pwd, "bevy_tdd_book"))
+
+args <- paste0("clone https://github.com/richelbilderbeek/bevy_tdd_book_", chapter_names)
+
+for (arg in args) {
+  system2(command = "git", args = arg)  
+}