Try #726:

Makefile

@@ -70,12 +70,13 @@ wasitests-singlepass: wasitests-setup
 	cargo test --manifest-path lib/wasi-tests/Cargo.toml --release --features singlepass -- --test-threads=1
 
 wasitests-cranelift: wasitests-setup
-	cargo test --manifest-path lib/wasi-tests/Cargo.toml --release --features clif -- --test-threads=1
+	cargo test --manifest-path lib/wasi-tests/Cargo.toml --release --features clif -- --test-threads=1 --nocapture
 
 wasitests-llvm: wasitests-setup
 	cargo test --manifest-path lib/wasi-tests/Cargo.toml --release --features llvm -- --test-threads=1
 
-wasitests-unit:
+wasitests-unit: wasitests-setup
+	cargo test --manifest-path lib/wasi-tests/Cargo.toml --release --features clif -- --test-threads=1 --nocapture
 	cargo test --manifest-path lib/wasi/Cargo.toml --release
 
 wasitests: wasitests-unit wasitests-singlepass wasitests-cranelift wasitests-llvm

lib/wasi-tests/Cargo.toml

@@ -10,6 +10,7 @@ build = "build/mod.rs"
 
 [dependencies]
 wasmer-runtime-core = { path = "../runtime-core", version = "0.6.0" }
+wasmer-runtime = { path = "../runtime", version = "0.6.0" }
 wasmer-wasi = { path = "../wasi", version = "0.6.0" }
 # hack to get tests to work
 wasmer-singlepass-backend = { path = "../singlepass-backend", version = "0.6.0", optional = true }

lib/wasi-tests/src/lib.rs

@@ -1 +1,60 @@
-// nothing to see here
+#![cfg(test)]
+use wasmer_runtime::{compile, Func};
+use wasmer_runtime_core::vm::Ctx;
+use wasmer_wasi::{state::*, *};
+
+use std::ffi::c_void;
+
+#[test]
+fn serializing_works() {
+    let args = vec![
+        b"program_name".into_iter().cloned().collect(),
+        b"arg1".into_iter().cloned().collect(),
+    ];
+    let envs = vec![
+        b"PATH=/bin".into_iter().cloned().collect(),
+        b"GOROOT=$HOME/.cargo/bin".into_iter().cloned().collect(),
+    ];
+    let wasm_binary = include_bytes!("../wasitests/fd_read.wasm");
+    let import_object = generate_import_object(
+        args.clone(),
+        envs.clone(),
+        vec![],
+        vec![(
+            ".".to_string(),
+            std::path::PathBuf::from("wasitests/test_fs/hamlet"),
+        )],
+    );
+    let module = compile(&wasm_binary[..])
+        .map_err(|e| format!("Can't compile module: {:?}", e))
+        .unwrap();
+
+    let state_bytes = {
+        let instance = module.instantiate(&import_object).unwrap();
+
+        let start: Func<(), ()> = instance.func("_start").unwrap();
+        start.call().unwrap();
+        let state = get_wasi_state(instance.context());
+
+        assert_eq!(state.args, args);
+        assert_eq!(state.envs, envs);
+        let bytes = state.freeze().unwrap();
+
+        bytes
+    };
+
+    let mut instance = module.instantiate(&import_object).unwrap();
+
+    let wasi_state = Box::new(WasiState::unfreeze(&state_bytes).unwrap());
+
+    instance.context_mut().data = Box::into_raw(wasi_state) as *mut c_void;
+
+    let second_entry: Func<(), i32> = instance.func("second_entry").unwrap();
+    let result = second_entry.call().unwrap();
+    assert_eq!(result, true as i32);
+}
+
+#[allow(clippy::mut_from_ref)]
+pub(crate) fn get_wasi_state(ctx: &Ctx) -> &mut WasiState {
+    unsafe { state::get_wasi_state(&mut *(ctx as *const Ctx as *mut Ctx)) }
+}

lib/wasi-tests/tests/wasitests/fd_read.rs

@@ -0,0 +1,14 @@
+#[test]
+fn test_fd_read() {
+    assert_wasi_output!(
+        "../../wasitests/fd_read.wasm",
+        "fd_read",
+        vec![],
+        vec![(
+            ".".to_string(),
+            ::std::path::PathBuf::from("wasitests/test_fs/hamlet")
+        ),],
+        vec![],
+        "../../wasitests/fd_read.out"
+    );
+}

lib/wasi-tests/tests/wasitests/mod.rs

@@ -9,6 +9,7 @@ mod create_dir;
 mod envvar;
 mod fd_allocate;
 mod fd_pread;
+mod fd_read;
 mod fd_sync;
 mod file_metadata;
 mod fs_sandbox_test;

lib/wasi-tests/wasitests/fd_read.out

@@ -0,0 +1,3 @@
+SCENE IV. The Queen's closet.
+
+    Enter QUEEN GERTRUDE and POLO

lib/wasi-tests/wasitests/fd_read.rs

@@ -0,0 +1,86 @@
+// Args:
+// mapdir: .:wasitests/test_fs/hamlet
+
+// this program is used in the pause/resume test
+
+use std::fs;
+#[cfg(target_os = "wasi")]
+use std::os::wasi::prelude::AsRawFd;
+use std::path::PathBuf;
+
+#[cfg(target_os = "wasi")]
+#[repr(C)]
+struct WasiIovec {
+    pub buf: u32,
+    pub buf_len: u32,
+}
+
+#[cfg(target_os = "wasi")]
+#[link(wasm_import_module = "wasi_unstable")]
+extern "C" {
+    fn fd_read(fd: u32, iovs: u32, iovs_len: u32, nread: u32) -> u16;
+}
+
+#[cfg(target_os = "wasi")]
+fn read(fd: u32, iovs: &[&mut [u8]]) -> u32 {
+    let mut nread = 0;
+    let mut processed_iovs = vec![];
+
+    for iov in iovs {
+        processed_iovs.push(WasiIovec {
+            buf: iov.as_ptr() as usize as u32,
+            buf_len: iov.len() as u32,
+        })
+    }
+
+    unsafe {
+        fd_read(
+            fd,
+            processed_iovs.as_ptr() as usize as u32,
+            processed_iovs.len() as u32,
+            &mut nread as *mut u32 as usize as u32,
+        );
+    }
+    nread
+}
+
+fn main() {
+    #[cfg(not(target_os = "wasi"))]
+    let mut base = PathBuf::from("wasitests/test_fs/hamlet");
+    #[cfg(target_os = "wasi")]
+    let mut base = PathBuf::from(".");
+
+    base.push("act3/scene4.txt");
+    let mut file = fs::File::open(&base).expect("Could not open file");
+    let mut buffer = [0u8; 64];
+
+    #[cfg(target_os = "wasi")]
+    {
+        let raw_fd = file.as_raw_fd();
+        assert_eq!(read(raw_fd, &[&mut buffer]), 64);
+        let str_val = std::str::from_utf8(&buffer[..]).unwrap().to_string();
+        println!("{}", &str_val);
+    }
+    // leak the file handle so that we can use it later
+    std::mem::forget(file);
+
+    #[cfg(not(target_os = "wasi"))]
+    {
+        // eh, just print the output directly
+        print!(
+            "SCENE IV. The Queen's closet.
+
+    Enter QUEEN GERTRUDE and POLO"
+        );
+    }
+}
+
+#[cfg(target_os = "wasi")]
+#[no_mangle]
+fn second_entry() -> bool {
+    let raw_fd = 5;
+    let mut buffer = [0u8; 8];
+    let result = read(raw_fd, &[&mut buffer]);
+
+    &buffer == b"NIUS \n\nL"
+}