Bug in DocX.SaveAs(fileName) is fixed. (Before fix the size of the resulting file was =0).

DocX/DocX.cs

             {
                 using (FileStream fs = new FileStream(filename, FileMode.Create))
                 {
-                    CopyStream(memoryStream, fs);
-                }
+					// Original code
+					// fs.Write( memoryStream.ToArray(), 0, (int)memoryStream.Length );
+					// was replaced by save using small buffer
+					// CopyStream( memoryStream, fs);
+					// Corection is to make position equal to 0
+					if(memoryStream.CanSeek)
+					{
+						// Write to the beginning of the stream
+						memoryStream.Position = 0;
+						CopyStream(memoryStream, fs);
+					}
+					else
+						fs.Write(memoryStream.ToArray(), 0, (int)memoryStream.Length);
+				}
             }
             else
             {

Examples/packages.config

+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="NUnit" version="3.6.0" targetFramework="net40" />
+  <package id="NUnitTestAdapter" version="2.0.0" targetFramework="net40" />
+</packages>

UnitTests/DocXUnitTests.cs

             }
         }
 
-        [Test]
+		[Test]
+		public void Test_DocX_SaveAs()
+		{
+			string temporaryFilePath = Path.Combine( _directoryDocuments, "temp.docx" );
+
+			// Load the document 'Paragraphs.docx'
+			using( DocX document = DocX.Load( Path.Combine( _directoryWithFiles, "Paragraphs.docx" ) ) )
+			{
+				document.InsertParagraph( "text" );
+
+				// Test the saving of the document.
+				document.SaveAs( temporaryFilePath );
+
+				// Check file size
+				FileInfo f = new FileInfo( temporaryFilePath );
+				Assert.IsTrue( f.Length == 9659 );
+			}
+
+			// Delete the tempory file.
+			File.Delete( temporaryFilePath );
+		}
+
+		[Test]
         public void TableWithSpecifiedWidths()
         {
             using (var output = File.Open(Path.Combine(_directoryWithFiles, "TableSpecifiedWidths.docx"), FileMode.Create))

UnitTests/UnitTests.csproj

     </AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="nunit.framework, Version=2.6.3.13283, Culture=neutral, PublicKeyToken=96d09a1eb7f44a77, processorArchitecture=MSIL">
-      <HintPath>..\packages\nunit.framework.2.63.0\lib\nunit.framework.dll</HintPath>
+    <Reference Include="nunit.framework, Version=3.6.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb, processorArchitecture=MSIL">
+      <HintPath>..\packages\NUnit.3.6.0\lib\net40\nunit.framework.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System" />

UnitTests/packages.config

 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="NUnit" version="3.4.1" targetFramework="net40" />
+  <package id="NUnit" version="3.6.0" targetFramework="net40" />
   <package id="NUnit.Console" version="3.4.1" targetFramework="net40" />
   <package id="NUnit.ConsoleRunner" version="3.4.1" targetFramework="net40" />
   <package id="NUnit.Extension.NUnitProjectLoader" version="3.4.1" targetFramework="net40" />