Fix Java project structure.

assets/src/main/Main.java

@@ -1,6 +1,12 @@
+package main;
+
 public class Main {
 
     public static void main(String[] args) {
         System.out.println("Hello, world!");
     }
+
+    public static int add(int a, int b) {
+        return a + b;
+    }
 }

assets/src/test/Main.java

@@ -0,0 +1,12 @@
+package test;
+
+public class Main {
+
+    public static void main(String[] args) {
+        testAdd();
+    }
+
+    public static void testAdd() {
+        assert main.Main.add(2, 2) == 4;
+    }
+}

src/fs.rs

@@ -10,7 +10,12 @@ pub fn expand_files<P: AsRef<Path>>(path: P) -> anyhow::Result<Vec<PathBuf>> {
     Ok(std::fs::read_dir(path)?
         .filter_map(|entry| {
             let path = entry.ok()?.path();
-            if path.is_file() { Some(path) } else { None }
+            if path.is_dir() {
+                Some(expand_files(path).ok()?)
+            } else {
+                Some(vec![path])
+            }
         })
+        .flatten()
         .collect())
 }

src/main.rs

@@ -18,8 +18,14 @@ use anyhow::Context;
 use bytesize::ByteSize;
 
 const DIR_TARGET: LazyLock<PathBuf> = LazyLock::new(|| PathBuf::from("target/"));
-const DIR_TEST: LazyLock<PathBuf> = LazyLock::new(|| PathBuf::from("test/"));
 const DIR_SRC: LazyLock<PathBuf> = LazyLock::new(|| PathBuf::from("src/"));
+/// Cannot flatten this dir out of existence due to IDEs, Linters,
+/// and probably also Java expecting it to exist.
+const DIR_MAIN: LazyLock<PathBuf> = LazyLock::new(|| DIR_SRC.join("main/"));
+/// Once again, I would love to pull this out of src/ and into parent, but
+/// I can't do that due to IDEs, linters, and probably also Java expecting it to exist in src/.
+const DIR_TEST: LazyLock<PathBuf> = LazyLock::new(|| DIR_SRC.join("test/"));
+
 const F_NEST_TOML: LazyLock<PathBuf> = LazyLock::new(|| PathBuf::from("Nest.toml"));
 const F_NEST_LOCK: LazyLock<PathBuf> = LazyLock::new(|| PathBuf::from("Nest.lock"));
 
@@ -77,8 +83,8 @@ fn init() -> anyhow::Result<()> {
         .to_owned();
 
     // Make src, target, tests
-    for dir in [DIR_SRC, DIR_TARGET, DIR_TEST] {
-        std::fs::create_dir(dir.clone())?;
+    for dir in [DIR_SRC, DIR_MAIN, DIR_TARGET, DIR_TEST] {
+        std::fs::create_dir_all(dir.clone())?;
     }
 
     // Make config file.
@@ -114,13 +120,24 @@ fn init() -> anyhow::Result<()> {
         )?;
     }
 
-    // Make Main.java
-    if let Result::Ok(mut f) = OpenOptions::new()
-        .write(true)
-        .create_new(is_empty)
-        .open(DIR_SRC.clone().join("Main").with_extension(JAVA_EXT_SOURCE))
-    {
-        f.write_all(include_bytes!("../assets/Main.java"))?;
+    // Make src/main/Main.java
+    if let Result::Ok(mut f) = OpenOptions::new().write(true).create_new(is_empty).open(
+        DIR_MAIN
+            .clone()
+            .join("Main")
+            .with_extension(JAVA_EXT_SOURCE),
+    ) {
+        f.write_all(include_bytes!("../assets/src/main/Main.java"))?;
+    }
+
+    // Make src/test/Main.java
+    if let Result::Ok(mut f) = OpenOptions::new().write(true).create_new(is_empty).open(
+        DIR_TEST
+            .clone()
+            .join("Main")
+            .with_extension(JAVA_EXT_SOURCE),
+    ) {
+        f.write_all(include_bytes!("../assets/src/test/Main.java"))?;
     }
 
     // git init .
@@ -133,7 +150,6 @@ fn init() -> anyhow::Result<()> {
         .read(true)
         .open(".gitignore")
     {
-        dbg!();
         let mut buf = String::new();
         f.read_to_string(&mut buf)?;
 
@@ -141,7 +157,7 @@ fn init() -> anyhow::Result<()> {
             DIR_TARGET.as_path().display().to_string(),
             format!("*.{}", JAVA_EXT_CLASS),
         ] {
-            if dbg!(!buf.contains(&ignored)) {
+            if !buf.contains(&ignored) {
                 f.write(format!("{}\n", ignored).as_bytes())?;
             }
         }
@@ -192,7 +208,7 @@ fn build() -> anyhow::Result<()> {
 
     for target in targets {
         println!("Compiling {}", target.display());
-        if javac.clone().compile(target.as_path()).is_ok()
+        if javac.clone().compile(dbg!(target.as_path())).is_ok()
             && let Result::Ok(class) = Class::try_from(target.clone())
         {
             nest_lock.0.insert(target, class);
@@ -212,6 +228,7 @@ fn run<P: AsRef<Path>>(
     entry_point: P,
     assertions: bool,
 ) -> anyhow::Result<(Option<String>, Option<String>)> {
+    // JRE pathing will be messed up without this.
     crate::env::set_cwd(DIR_TARGET.as_path())?;
 
     java::JVMBuilder::new()