Refactor the file input stream

tests/standalone/src/FileTest.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Dart test program for testing file I/O.
 
 
 class FileTest {
   static Directory tempDirectory;
   static int numLiveAsyncTests = 0;
@@ skipping 38 matching lines @@
     Expect.equals(114, buffer[7]);  // represents 'r' in the file.
     Expect.equals(105, buffer[8]);  // represents 'i' in the file.
     Expect.equals(103, buffer[9]);  // represents 'g' in the file.
     Expect.equals(104, buffer[10]);  // represents 'h' in the file.
     Expect.equals(116, buffer[11]);  // represents 't' in the file.
     return 1;
   }
 
   // Test for file read and write functionality.
   static int testReadWriteStream() {
-    // Read a file.
     String inFilename = getFilename("tests/vm/data/fixed_length_file");
-    File file = new File(inFilename);
-    InputStream input = file.openInputStream();
+    File file;
+    InputStream input;
+    int bytesRead;
+
+    // Test reading all using readInto.
+    file = new File(inFilename);
+    input = file.openInputStream();
     List<int> buffer1 = new List<int>(42);
-    int bytesRead = input.readInto(buffer1, 0, 42);
+    bytesRead = input.readInto(buffer1, 0, 42);
     Expect.equals(42, bytesRead);
     Expect.isTrue(input.closed);
+
+    // Test reading all using readInto and read.
+    file = new File(inFilename);
+    input = file.openInputStream();
+    bytesRead = input.readInto(buffer1, 0, 21);
+    Expect.equals(21, bytesRead);
+    buffer1 = input.read();
+    Expect.equals(21, buffer1.length);
+    Expect.isTrue(input.closed);
+
+    // Test reading all using read and readInto.
+    file = new File(inFilename);
+    input = file.openInputStream();
+    buffer1 = input.read(21);
+    Expect.equals(21, buffer1.length);
+    bytesRead = input.readInto(buffer1, 0, 21);
+    Expect.equals(21, bytesRead);
+    Expect.isTrue(input.closed);
+
+    // Test reading all using read.
+    file = new File(inFilename);
+    input = file.openInputStream();
+    buffer1 = input.read();
+    Expect.equals(42, buffer1.length);
+    Expect.isTrue(input.closed);
+
     // Write the contents of the file just read into another file.
     String outFilename = tempDirectory.path + "/out_read_write_stream";
     file = new File(outFilename);
     OutputStream output = file.openOutputStream();
     bool writeDone = output.writeFrom(buffer1, 0, 42);
     Expect.equals(true, writeDone);
     output.close();
+
     // Now read the contents of the file just written.
     List<int> buffer2 = new List<int>(42);
     file = new File(outFilename);
     input = file.openInputStream();
     bytesRead = input.readInto(buffer2, 0, 42);
     Expect.isTrue(input.closed);
     Expect.equals(42, bytesRead);
     // Now compare the two buffers to check if they are identical.
     for (int i = 0; i < buffer1.length; i++) {
       Expect.equals(buffer1[i],  buffer2[i]);
@@ skipping 399 matching lines @@
     return 1;
   }
 
   // Tests stream exception handling after file was closed.
   static int testCloseExceptionStream() {
     List<int> buffer = new List<int>(42);
     File file = new File(tempDirectory.path + "/out_close_exception_stream");
     file.createSync();
     InputStream input = file.openInputStream();
     Expect.isTrue(input.closed);
-    Expect.throws(( ) => input.readInto(buffer, 0, 12),
-                  (e) => e is FileIOException);
+    Expect.isNull(input.readInto(buffer, 0, 12));
     OutputStream output = file.openOutputStream();
     output.close();
     Expect.throws(( ) => output.writeFrom(buffer, 0, 12),
                   (e) => e is FileIOException);
     file.deleteSync();
     return 1;
   }
 
   // Tests buffer out of bounds exception.
   static int testBufferOutOfBoundsException() {
@@ skipping 137 matching lines @@
         Expect.equals(1, testCloseExceptionStream());
         Expect.equals(1, testBufferOutOfBoundsException());
         asyncTestDone();
       });
   }
 }
 
 main() {
   FileTest.testMain();
 }