Reorganize wasi-misc-tests. (#575)

* Reorganize wasi-misc-tests.

Move wasi-misc-tests out of wasi-common, to break a dependency cycle;
previously, wasmtime-* depended on wasi-common, but wasi-common
dev-dependended on wasmtime-*.

Now, wasi-common no longer dev-depends on wasmtime-*; instead, the
tests are in their own crate which depends on wasi-common and on
wasmtime-*.

Also, rename wasi-misc-tests to wasi-tests for simplicity.

This also removes the "wasm_tests" feature; it's replaced by the
"test-programs" feature.

* Update the CI script to use the new feature name.

* Update the CI script to use the new feature name in one more place.

* Change a `write!` to a `writeln!`.

crates/test-programs/wasi-tests/src/bin/file_seek_tell.rs

@@ -0,0 +1,133 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::utils::{cleanup_file, close_fd};
+use wasi_tests::wasi_wrappers::{wasi_fd_seek, wasi_fd_tell, wasi_fd_write, wasi_path_open};
+
+unsafe fn test_file_seek_tell(dir_fd: wasi_unstable::Fd) {
+    // Create a file in the scratch directory.
+    let mut file_fd = wasi_unstable::Fd::max_value() - 1;
+    let mut status = wasi_path_open(
+        dir_fd,
+        0,
+        "file",
+        wasi_unstable::O_CREAT,
+        wasi_unstable::RIGHT_FD_READ | wasi_unstable::RIGHT_FD_WRITE,
+        0,
+        0,
+        &mut file_fd,
+    );
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "opening a file"
+    );
+    assert_gt!(
+        file_fd,
+        libc::STDERR_FILENO as wasi_unstable::Fd,
+        "file descriptor range check",
+    );
+
+    // Check current offset
+    let mut offset: wasi_unstable::FileSize = 0;
+    status = wasi_fd_tell(file_fd, &mut offset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "getting initial file offset"
+    );
+    assert_eq!(offset, 0, "current offset should be 0");
+
+    // Write to file
+    let buf = &[0u8; 100];
+    let iov = wasi_unstable::CIoVec {
+        buf: buf.as_ptr() as *const _,
+        buf_len: buf.len(),
+    };
+    let iovs = &[iov];
+    let mut nwritten = 0;
+    status = wasi_fd_write(file_fd, iovs, &mut nwritten);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "writing to a file"
+    );
+    assert_eq!(nwritten, 100, "should write 100 bytes to file");
+
+    // Check current offset
+    status = wasi_fd_tell(file_fd, &mut offset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "getting file offset after writing"
+    );
+    assert_eq!(offset, 100, "offset after writing should be 100");
+
+    // Seek to middle of the file
+    let mut newoffset = 1;
+    status = wasi_fd_seek(file_fd, -50, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "seeking to the middle of a file"
+    );
+    assert_eq!(
+        newoffset, 50,
+        "offset after seeking to the middle should be at 50"
+    );
+
+    // Seek to the beginning of the file
+    status = wasi_fd_seek(file_fd, 0, wasi_unstable::WHENCE_SET, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "seeking to the beginning of the file"
+    );
+    assert_eq!(
+        newoffset, 0,
+        "offset after seeking to the beginning of the file should be at 0"
+    );
+
+    // Seek beyond the file should be possible
+    status = wasi_fd_seek(file_fd, 1000, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "seeking beyond the end of the file"
+    );
+
+    // Seek before byte 0 is an error though
+    status = wasi_fd_seek(file_fd, -2000, wasi_unstable::WHENCE_CUR, &mut newoffset);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_EINVAL,
+        "seeking before byte 0 is an error"
+    );
+
+    close_fd(file_fd);
+    cleanup_file(dir_fd, "file");
+}
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_file_seek_tell(dir_fd) }
+}