test is_terminal

tests/pass/shims/fs.rs

@@ -3,14 +3,15 @@
 
 #![feature(io_error_more)]
 #![feature(io_error_uncategorized)]
+#![feature(is_terminal)]
 
 use std::collections::HashMap;
 use std::ffi::OsString;
 use std::fs::{
     canonicalize, create_dir, read_dir, read_link, remove_dir, remove_dir_all, remove_file, rename,
     File, OpenOptions,
 };
-use std::io::{Error, ErrorKind, Read, Result, Seek, SeekFrom, Write};
+use std::io::{Error, ErrorKind, IsTerminal, Read, Result, Seek, SeekFrom, Write};
 use std::path::{Path, PathBuf};
 
 fn main() {
@@ -91,6 +92,8 @@ fn test_file() {
     file.read_to_end(&mut contents).unwrap();
     assert_eq!(bytes, contents.as_slice());
 
+    assert!(!file.is_terminal());
+
     // Removing file should succeed.
     remove_file(&path).unwrap();
 }

tests/pass/shims/io.rs

@@ -0,0 +1,9 @@
+#![feature(is_terminal)]
+
+use std::io::IsTerminal;
+
+fn main() {
+    // We can't really assume that this is truly a terminal, and anyway on Windows Miri will always
+    // return `false` here, but we can check that the call succeeds.
+    std::io::stdout().is_terminal();
+}