add, fix tests

crates/wasi-c2/src/random.rs

@@ -5,6 +5,8 @@ pub trait WasiRandom {
     fn get(&self, buf: &mut [u8]) -> Result<(), Error>;
 }
 
+/// Implement `WasiRandom` using the `getrandom` crate, which selects your system's best entropy
+/// source.
 pub struct GetRandom;
 
 impl WasiRandom for GetRandom {
@@ -14,6 +16,7 @@ impl WasiRandom for GetRandom {
     }
 }
 
+/// Implement `WasiRandom` using a deterministic cycle of bytes.
 pub struct Deterministic {
     sequence: RefCell<std::iter::Cycle<std::vec::IntoIter<u8>>>,
 }
@@ -35,3 +38,17 @@ impl WasiRandom for Deterministic {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    #[test]
+    fn deterministic() {
+        let det = Deterministic::new(vec![1, 2, 3, 4]);
+        let mut buf = vec![0; 1024];
+        det.get(&mut buf).expect("get randomness");
+        for (ix, b) in buf.iter().enumerate() {
+            assert_eq!(*b, (ix % 4) as u8 + 1)
+        }
+    }
+}

crates/wasi-c2/src/virt/pipe.rs

@@ -20,11 +20,11 @@ use system_interface::fs::{Advice, FileIoExt};
 /// A variety of `From` impls are provided so that common pipe types are easy to create. For example:
 ///
 /// ```
-/// # use wasi_c2::WasiCtxBuilder;
+/// # use wasi_c2::WasiCtx;
 /// # use wasi_c2::virt::pipe::ReadPipe;
 /// let mut ctx = WasiCtx::builder();
 /// let stdin = ReadPipe::from("hello from stdin!");
-/// ctx.stdin(stdin);
+/// ctx.stdin(Box::new(stdin));
 /// ```
 #[derive(Debug)]
 pub struct ReadPipe<R: Read> {
@@ -207,6 +207,18 @@ impl<R: Read> WasiFile for ReadPipe<R> {
 }
 
 /// A virtual pipe write end.
+///
+/// ```
+/// # use wasi_c2::WasiCtx;
+/// # use wasi_c2::virt::pipe::WritePipe;
+/// let mut ctx = WasiCtx::builder();
+/// let stdout = WritePipe::new_in_memory();
+/// ctx.stdout(Box::new(stdout.clone()));
+/// // use ctx in an instance, then make sure it is dropped:
+/// drop(ctx);
+/// let contents: Vec<u8> = stdout.try_into_inner().expect("sole remaining reference to WritePipe").into_inner();
+/// println!("contents of stdout: {:?}", contents);
+/// ```
 #[derive(Debug)]
 pub struct WritePipe<W: Write> {
     writer: Arc<RwLock<W>>,