Fixed StreamReader._read_nowait (#1297)

* Fixed StreamReader._read_nowait

* Added an entry to CHANGES

CHANGES.rst

@@ -4,7 +4,8 @@ CHANGES
 1.0.5 (XXXX-XX-XX)
 ------------------
 
--
+- Fix StreamReader._read_nowait to return all available 
+  data up to the requested amount
 
 -
 

aiohttp/streams.py

@@ -242,7 +242,7 @@ def readline(self):
                 offset = self._buffer_offset
                 ichar = self._buffer[0].find(b'\n', offset) + 1
                 # Read from current offset to found b'\n' or to the end.
-                data = self._read_nowait(ichar - offset if ichar else -1)
+                data = self._read_nowait_chunk(ichar - offset if ichar else -1)
                 line.append(data)
                 line_size += len(data)
                 if ichar:
@@ -340,10 +340,7 @@ def read_nowait(self, n=-1):
 
         return self._read_nowait(n)
 
-    def _read_nowait(self, n):
-        if not self._buffer:
-            return EOF_MARKER
-
+    def _read_nowait_chunk(self, n):
         first_buffer = self._buffer[0]
         offset = self._buffer_offset
         if n != -1 and len(first_buffer) - offset > n:
@@ -361,6 +358,19 @@ def _read_nowait(self, n):
         self._buffer_size -= len(data)
         return data
 
+    def _read_nowait(self, n):
+        chunks = []
+
+        while self._buffer:
+            chunk = self._read_nowait_chunk(n)
+            chunks.append(chunk)
+            if n != -1:
+                n -= len(chunk)
+                if n == 0:
+                    break
+
+        return b''.join(chunks) if chunks else EOF_MARKER
+
 
 class EmptyStreamReader(AsyncStreamReaderMixin):
 

tests/test_streams.py

@@ -124,6 +124,28 @@ def test_read_line_breaks(self):
         data = self.loop.run_until_complete(stream.read(5))
         self.assertEqual(b'line2', data)
 
+    def test_read_all(self):
+        # Read all avaliable buffered bytes
+        stream = self._make_one()
+        stream.feed_data(b'line1')
+        stream.feed_data(b'line2')
+        stream.feed_eof()
+
+        data = self.loop.run_until_complete(stream.read())
+        self.assertEqual(b'line1line2', data)
+
+    def test_read_up_to(self):
+        # Read available buffered bytes up to requested amount
+        stream = self._make_one()
+        stream.feed_data(b'line1')
+        stream.feed_data(b'line2')
+
+        data = self.loop.run_until_complete(stream.read(8))
+        self.assertEqual(b'line1lin', data)
+
+        data = self.loop.run_until_complete(stream.read(8))
+        self.assertEqual(b'e2', data)
+
     def test_read_eof(self):
         # Read bytes, stop at eof.
         stream = self._make_one()