CSHARP-1993: Refactor pull request.

Author: rstam

README.md

@@ -101,6 +101,7 @@ Please see our [guidelines](CONTRIBUTING.md) for contributing to the driver.
 * Jacob Jewell              [email protected]
 * Danny Kendrick            https://github.com/dkendrick
 * Brian Knight              [email protected]  
+* Anatoly Koperin           https://github.com/ExM
 * Nik Kolev                 [email protected]
 * Oleg Kosmakov             [email protected]
 * Maksim Krautsou           https://github.com/MaKCbIMKo

src/MongoDB.Driver.GridFS/GridFSSeekableDownloadStream.cs

@@ -1,4 +1,4 @@
-/* Copyright 2015-2016 MongoDB Inc.
+/* Copyright 2015-2017 MongoDB Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -125,16 +125,16 @@ public override long Seek(long offset, SeekOrigin origin)
             {
                 case SeekOrigin.Begin: newPosition = offset; break;
                 case SeekOrigin.Current: newPosition = _position + offset; break;
-                case SeekOrigin.End: newPosition = FileInfo.Length + offset; break;
+                case SeekOrigin.End: newPosition = Length + offset; break;
                 default: throw new ArgumentException("Invalid origin.", "origin");
             }
             if (newPosition < 0)
             {
                 throw new IOException("Position must be greater than or equal to zero.");
             }
-            if (FileInfo.Length <= newPosition)
+            if (newPosition > Length)
             {
-                throw new IOException("Position must be less than to length of stream.");
+                throw new IOException("Position must be less than or equal to the length of the stream.");
             }
             Position = newPosition;
             return newPosition;

tests/MongoDB.Driver.GridFS.Tests/GridFSSeekableDownloadStreamTests.cs

@@ -1,4 +1,4 @@
-/* Copyright 2015-2016 MongoDB Inc.
+/* Copyright 2015-2017 MongoDB Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -195,7 +195,7 @@ public void Read_should_throw_when_offset_is_invalid(int bufferLength, int offse
         [InlineData(9, 1, SeekOrigin.Begin, 1)]
         [InlineData(0, 1, SeekOrigin.Current, 1)]
         [InlineData(5, 1, SeekOrigin.Current, 6)]
-        [InlineData(8, 1, SeekOrigin.Current, 9)]
+        [InlineData(9, 1, SeekOrigin.Current, 10)]
         [InlineData(0, -1, SeekOrigin.End, 9)]
         [InlineData(5, -1, SeekOrigin.End, 9)]
         [InlineData(9, -1, SeekOrigin.End, 9)]
@@ -216,13 +216,22 @@ public void Seek_should_return_expected_result(
         [Theory]
         [InlineData(0, -1, SeekOrigin.Begin)]
         [InlineData(5, -1, SeekOrigin.Begin)]
-        [InlineData(9, 10, SeekOrigin.Begin)]
+        [InlineData(10, -1, SeekOrigin.Begin)]
+        [InlineData(0, 11, SeekOrigin.Begin)]
+        [InlineData(5, 11, SeekOrigin.Begin)]
+        [InlineData(10, 11, SeekOrigin.Begin)]
         [InlineData(0, -1, SeekOrigin.Current)]
         [InlineData(5, -6, SeekOrigin.Current)]
-        [InlineData(8, 3, SeekOrigin.Current)]
-        [InlineData(0, 0, SeekOrigin.End)]
+        [InlineData(10, -11, SeekOrigin.Current)]
+        [InlineData(0, 11, SeekOrigin.Current)]
+        [InlineData(5, 6, SeekOrigin.Current)]
+        [InlineData(10, 1, SeekOrigin.Current)]
+        [InlineData(0, 1, SeekOrigin.End)]
         [InlineData(5, 1, SeekOrigin.End)]
-        [InlineData(9, -11, SeekOrigin.End)]
+        [InlineData(10, 1, SeekOrigin.End)]
+        [InlineData(0, -11, SeekOrigin.End)]
+        [InlineData(5, -11, SeekOrigin.End)]
+        [InlineData(10, -11, SeekOrigin.End)]
         public void Seek_should_throw_when_new_position_is_out_of_range(
             long position,
             long offset,