add tests for io::readchars and io::readchar

Additionally reformat so that 'make check' passes.

src/libstd/io.rs

@@ -130,26 +130,29 @@ obj new_reader(rdr: buf_reader) {
                     val += next & 63 as uint;
                 }
                 // See str::char_at
-                val += (b0 << (w + 1u as u8) as uint) << (w - 1u) * 6u - w - 1u;
+                val += (b0 << (w + 1u as u8) as uint)
+                    << (w - 1u) * 6u - w - 1u;
                 chars += [ val as char ];
             }
             ret (i, 0u);
         }
         let buf: [u8] = [];
         let chars: [char] = [];
-        let nbread = n; // might need more bytes, but reading n will never over-read
+        // might need more bytes, but reading n will never over-read
+        let nbread = n;
         while nbread > 0u {
-            let data = self.read_bytes(nbread); 
+            let data = self.read_bytes(nbread);
             if vec::len(data) == 0u {
-                // eof - FIXME should we do something if we're split in a unicode char?
+                // eof - FIXME should we do something if
+                // we're split in a unicode char?
                 break;
             }
             buf += data;
             let (offset, nbreq) = chars_from_buf(buf, chars);
             let ncreq = n - vec::len(chars);
-            // again we either know we need a certain number of bytes to complete a
+            // again we either know we need a certain number of bytes
-            // character, or we make sure we don't over-read by reading 1-byte per char
+            // to complete a character, or we make sure we don't
-            // needed
+            // over-read by reading 1-byte per char needed
             nbread = if ncreq > nbreq { ncreq } else { nbreq };
             if nbread > 0u {
                 buf = vec::slice(buf, offset, vec::len(buf));

src/test/stdtest/io.rs

@@ -23,6 +23,54 @@ fn test_simple() {
     assert (str::eq(frood, frood2));
 }
 
+#[test]
+fn test_readchars_empty() {
+    let inp : io::reader = io::string_reader("");
+    let res : [char] = inp.read_chars(128u);
+    assert(vec::len(res) == 0u);
+}
+
+#[test]
+fn test_readchars_wide() {
+    let wide_test = "生锈的汤匙切肉汤hello生锈的汤匙切肉汤";
+    let ivals : [int] = [
+        29983, 38152, 30340, 27748,
+        21273, 20999, 32905, 27748,
+        104, 101, 108, 108, 111,
+        29983, 38152, 30340, 27748,
+        21273, 20999, 32905, 27748];
+    fn check_read_ln(len : uint, s: str, ivals: [int]) {
+        let inp : io::reader = io::string_reader(s);
+        let res : [char] = inp.read_chars(len);
+        if (len <= vec::len(ivals)) {
+            assert(vec::len(res) == len);
+        }
+        assert(vec::slice(ivals, 0u, vec::len(res)) ==
+               vec::map(res, {|x| x as int}));
+    }
+    let i = 0u;
+    while i < 8u {
+        check_read_ln(i, wide_test, ivals);
+        i += 1u;
+    }
+    // check a long read for good measure
+    check_read_ln(128u, wide_test, ivals);
+}
+
+#[test]
+fn test_readchar() {
+    let inp : io::reader = io::string_reader("生");
+    let res : char = inp.read_char();
+    assert(res as int == 29983);
+}
+
+#[test]
+fn test_readchar_empty() {
+    let inp : io::reader = io::string_reader("");
+    let res : char = inp.read_char();
+    assert(res as int == -1);
+}
+
 #[test]
 fn file_reader_not_exist() {
     alt io::file_reader("not a file") {