Enable Nullable Reference Types (NRT) (#30)

* Migrate project MailMergeLib
* MailMergeMessage_Exceptions: Allow null for inner Exception
* Migrate project MailMergeLib.Tests

Src/MailMergeLib.Tests/EmailValidatorTest.cs

@@ -171,6 +171,6 @@ public void TestValidInternationalAddresses()
     [Test]
     public void TestThrowsExceptionIfNull()
     {
-        Assert.Throws<ArgumentNullException>(() => EmailValidator.Validate(null, true, true), "Null Address");
+        Assert.Throws<ArgumentNullException>(() => EmailValidator.Validate(null!, true, true), "Null Address");
     }
 }

Src/MailMergeLib.Tests/FakeSmtpClient.cs

@@ -23,9 +23,9 @@ public FakeSmtpClient()
         prop?.SetValue(this, SmtpCapabilities.Authentication);
     }
 
-    public Exception AuthenticateException { get; set; } = null;
-    public Exception ConnectException { get; set; } = null;
-    public Exception SendException { get; set; } = null;
+    public Exception? AuthenticateException { get; set; } = null;
+    public Exception? ConnectException { get; set; } = null;
+    public Exception? SendException { get; set; } = null;
 
     public override Task AuthenticateAsync(SaslMechanism mechanism, CancellationToken cancellationToken = new CancellationToken())
     {
@@ -77,13 +77,13 @@ public override Task ConnectAsync(Stream stream, string host, int port = 0, Secu
     }
 
     public override Task<string> SendAsync(FormatOptions options, MimeMessage message,
-        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress progress = null)
+        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress? progress = null)
     {
         throw new NotImplementedException(); 
     }
 
     public override Task<string> SendAsync(FormatOptions options, MimeMessage message, MailboxAddress sender, IEnumerable<MailboxAddress> recipients,
-        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress progress = null)
+        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress? progress = null)
     {
         throw new NotImplementedException();
     }
@@ -163,14 +163,14 @@ protected override void OnRecipientNotAccepted(MimeMessage message, MailboxAddre
     }
 
     public override string Send(FormatOptions options, MimeMessage message, CancellationToken cancellationToken = new CancellationToken(),
-        ITransferProgress progress = null)
+        ITransferProgress? progress = null)
     {
         if (SendException != null) throw SendException;
         return string.Empty;
     }
 
     public override string Send(FormatOptions options, MimeMessage message, MailboxAddress sender, IEnumerable<MailboxAddress> recipients,
-        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress progress = null)
+        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress? progress = null)
     {
         if (SendException != null) throw SendException;
         return string.Empty;
@@ -187,29 +187,29 @@ public override string Send(FormatOptions options, MimeMessage message, MailboxA
     */
 
     public override string Send(MimeMessage message, CancellationToken cancellationToken = new CancellationToken(),
-        ITransferProgress progress = null)
+        ITransferProgress? progress = null)
     {
         if (SendException != null) throw SendException;  // in use
         return string.Empty;
     }
 
     public override Task<string> SendAsync(MimeMessage message, CancellationToken cancellationToken = new CancellationToken(),
-        ITransferProgress progress = null)
+        ITransferProgress? progress = null)
     {
         if (SendException != null) throw SendException;
 
         return Task.FromResult(string.Empty);
     }
 
     public override string Send(MimeMessage message, MailboxAddress sender, IEnumerable<MailboxAddress> recipients,
-        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress progress = null)
+        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress? progress = null)
     {
         if (SendException != null) throw SendException;
         return string.Empty;
     }
 
     public override Task<string> SendAsync(MimeMessage message, MailboxAddress sender, IEnumerable<MailboxAddress> recipients,
-        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress progress = null)
+        CancellationToken cancellationToken = new CancellationToken(), ITransferProgress? progress = null)
     {
         if (SendException != null) throw SendException;
 

Src/MailMergeLib.Tests/FileMessageInfo.cs

@@ -23,8 +23,8 @@ public void CompareFileMessageInfo()
     [Test]
     public void CompareNullFileMessageInfo()
     {
-        var info = new MailMergeLib.MessageStore.FileMessageInfo { Id = 1, Category = null, Comments = null, Description = "No description", Data = "Some data hint", MessageEncoding = null, MessageFile = null };
-        var otherInfo = new MailMergeLib.MessageStore.FileMessageInfo { Id = 1, Category = null, Comments = null, Description = "No description", Data = "Some data hint", MessageEncoding = null, MessageFile = null };
+        var info = new MailMergeLib.MessageStore.FileMessageInfo { Id = 1, Category = null, Comments = null, Description = "No description", Data = "Some data hint", MessageEncoding = null!, MessageFile = null! };
+        var otherInfo = new MailMergeLib.MessageStore.FileMessageInfo { Id = 1, Category = null, Comments = null, Description = "No description", Data = "Some data hint", MessageEncoding = null!, MessageFile = null! };
 
         Assert.AreEqual(info, otherInfo);
         Assert.IsFalse(info.Equals(null));

Src/MailMergeLib.Tests/FileMessageStore_Serialization.cs

@@ -64,8 +64,6 @@ public void StreamSerialization()
         Assert.True(fms.Equals(restoredFms));
 
         Assert.AreEqual(fms.GetHashCode(), restoredFms.GetHashCode());
-        Assert.False(fms.Equals(null));
-        Assert.True(fms.Equals(fms));
         Assert.False(fms.Equals(new object()));
     }
 }

Src/MailMergeLib.Tests/Helper.cs

@@ -16,10 +16,10 @@ internal class Helper
     /// <returns></returns>
     public static string GetCodeBaseDirectory()
     {
-        return Path.GetDirectoryName(new Uri(Assembly.GetExecutingAssembly().Location).LocalPath);
+        return Path.GetDirectoryName(new Uri(Assembly.GetExecutingAssembly().Location).LocalPath)!;
     }
 
-    internal static int Compare(Stream a, Stream b)
+    internal static int Compare(Stream? a, Stream? b)
     {
         if (a == null && b == null) return 0;
 

Src/MailMergeLib.Tests/HtmlBodyBuilderTest.cs

@@ -13,7 +13,7 @@ public void SetHtmlBuilderDocBaseUri_UriFormatException(string baseUri)
     {
         var mmm = new MailMergeMessage("subject", "plain text",
             "<html><head><base href=\"\" /></head><body></body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         Assert.Throws<UriFormatException>(() => hbb.DocBaseUri = baseUri);
     }
 
@@ -26,7 +26,7 @@ public void SetHtmlBuilderDocBaseUri_NoException(string baseUri)
     {
         var mmm = new MailMergeMessage("subject", "plain text",
             "<html><head><base href=\"\" /></head><body></body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         Assert.DoesNotThrow(() => hbb.DocBaseUri = baseUri);
     }
 
@@ -35,7 +35,7 @@ public void ScriptTagRemoved()
     {
         var mmm = new MailMergeMessage("subject_to_set", "plain text",
             "<html><head><script>var x='x';</script><script>var y='y';</script></head><body>some body</body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         var html = hbb.GetBodyPart();
         Assert.IsTrue(html.ToString().Contains("some body"));
         Assert.IsTrue(!html.ToString().Contains("script"));
@@ -47,7 +47,7 @@ public void ExistingTitleTagSetWithSubject()
         var subjectToSet = "subject_to_set";
         var mmm = new MailMergeMessage(subjectToSet, "plain text",
             "<html><head><title>abc</title></head><body></body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         var html = hbb.GetBodyPart();
         Assert.IsTrue(html.ToString().Contains(subjectToSet));
     }
@@ -57,7 +57,7 @@ public void NonExistingTitleTagSetWithSubject()
     {
         var subjectToSet = "subject_to_set";
         var mmm = new MailMergeMessage(subjectToSet, "plain text", "<html><head></head><body></body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         var html = hbb.GetBodyPart();
         Assert.IsTrue(!html.ToString().Contains(subjectToSet));
     }
@@ -69,7 +69,7 @@ public void EmbeddedDataImage_ShouldNotBeTouched()
         var imageTag = $"<img width=\"10\" height=\"10\" alt=\"1Pixel\" src=\"{image}\">";
         var mmm = new MailMergeMessage("", "plain text",
             $"<html><body>{imageTag}</body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         var html = hbb.GetBodyPart();
         Assert.That(html.ToString(), Does.Contain(imageTag));
     }
@@ -85,7 +85,7 @@ public void LargeEmbeddedDataImage_ShouldNotThrow()
         var imageTag = $"<img width=\"10\" height=\"10\" alt=\"1Pixel\" src=\"{image}\">";
         var mmm = new MailMergeMessage("", "plain text",
             $"<html><body>{imageTag}</body></html>");
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         Assert.That(code: () => hbb.GetBodyPart(), Throws.Nothing);
     }
 }

Src/MailMergeLib.Tests/MailMergeLib.Tests.csproj

@@ -10,7 +10,7 @@
         <SignAssembly>true</SignAssembly>
         <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
         <IsTestProject>true</IsTestProject>
-        <Nullable>disable</Nullable>
+        <Nullable>enable</Nullable>
         <LangVersion>latest</LangVersion>
     </PropertyGroup>
 

Src/MailMergeLib.Tests/MessageInfo.cs

@@ -24,7 +24,6 @@ public void ReadAndCompareInfo()
         // MessageInfo
         var deserializedInfo = MailMergeLib.MessageStore.MessageInfoBase.Read(xml);
         Assert.AreEqual(info, deserializedInfo);
-        Assert.IsFalse(info.Equals(null));
         Assert.IsTrue(info.Equals(info));
         Assert.IsFalse(info.Equals(new object()));
         Assert.AreEqual(info.GetHashCode(), deserializedInfo.GetHashCode());
@@ -44,7 +43,6 @@ public void ReadAndCompareEmptyInfo()
         // MessageInfo
         var deserializedInfo = MailMergeLib.MessageStore.MessageInfoBase.Read(xml);
         Assert.AreEqual(info, deserializedInfo);
-        Assert.IsFalse(info.Equals(null));
         Assert.IsTrue(info.Equals(info));
         Assert.IsFalse(info.Equals(new object()));
         Assert.AreEqual(info.GetHashCode(), deserializedInfo.GetHashCode());

Src/MailMergeLib.Tests/Message_Config.cs

@@ -69,19 +69,19 @@ public void FileBaseDirectory_must_be_full_path_when_processing_the_message(stri
     [TestCase("noFullPath", null)]
     [TestCase("..\\..\\relativePath", null, ExcludePlatform = nameof(OpSys.Linux) + "," + nameof(OpSys.MacOsX))]
     [TestCase("../../relativePath", null, IncludePlatform = nameof(OpSys.Linux) + "," + nameof(OpSys.MacOsX))]
-    public void HtmlBodyBuilderDocBaseUri_vs_MessageConfig_FileBaseDirectory(string path, string expected)
+    public void HtmlBodyBuilderDocBaseUri_vs_MessageConfig_FileBaseDirectory(string path, string? expected)
     {
         var mmm = new MailMergeMessage("subject", "plain text", "<html><body></body></html>");
         mmm.Config.FileBaseDirectory = path;
 
         HtmlBodyBuilder hbb;
         if (expected == null)
         {
-            Assert.Throws<UriFormatException>(() => { hbb = new HtmlBodyBuilder(mmm, (object) null); });
+            Assert.Throws<UriFormatException>(() => { hbb = new HtmlBodyBuilder(mmm, null); });
         }
         else
         {
-            hbb = new HtmlBodyBuilder(mmm, (object) null);
+            hbb = new HtmlBodyBuilder(mmm, null);
             Assert.AreEqual(expected, hbb.DocBaseUri);
         }
     }
@@ -93,7 +93,7 @@ public void MessageConfig_FileBaseDirectory_cannot_be_changed_by_Html_Base_Tag()
             "<html><head><base href=\"\" /></head><body></body></html>");
         mmm.Config.FileBaseDirectory = Path.GetTempPath();
 
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         Assert.AreEqual( new Uri(mmm.Config.FileBaseDirectory), hbb.DocBaseUri);
     }
 
@@ -105,7 +105,7 @@ public void Empty_MessageConfig_FileBaseDirectory_is_changed_by_Html_Base_Tag()
             $"<html><head><base href=\"{baseTagHref}\" /></head><body></body></html>");
         mmm.Config.FileBaseDirectory = string.Empty;
 
-        var hbb = new HtmlBodyBuilder(mmm, (object) null);
+        var hbb = new HtmlBodyBuilder(mmm, null);
         hbb.GetBodyPart();
         Assert.AreEqual(baseTagHref, hbb.DocBaseUri);
     }

Src/MailMergeLib.Tests/Message_Equality.cs

@@ -35,7 +35,6 @@ public void MailMergeAddressCollectionEquality()
 
         addrColl2.Add(_addr3);
         Assert.False(addrColl1.Equals(addrColl2));
-        Assert.False(addrColl1.Equals(null));
     }
 
     [TestCase(MailAddressType.To)]
@@ -128,7 +127,6 @@ public void MailMergeMessage()
         mmm3.MailMergeAddresses.RemoveAt(0);
         Assert.IsFalse(mmm1.Equals(mmm3));
 
-        Assert.IsFalse(mmm1.Equals(default(object)));
         Assert.IsTrue(mmm1.Equals(mmm1));
         Assert.IsFalse(mmm1.Equals(new object()));
     }

Src/MailMergeLib.Tests/Message_Html.cs

@@ -126,8 +126,7 @@ public void HtmlStreamAttachments()
         Assert.IsTrue(mmm.StreamAttachments.Count == 1);
         mmm.StreamAttachments.Clear();
         Assert.IsTrue(mmm.StreamAttachments.Count == 0);
-        mmm.StreamAttachments = null;
-        Assert.IsTrue(mmm.StreamAttachments != null && mmm.StreamAttachments.Count == 0);
+
         mmm.StreamAttachments = streamAttachments;
         Assert.IsTrue(mmm.StreamAttachments.Count == 2);
     }
@@ -154,7 +153,7 @@ public void HtmlMailMergeWithStreamAttachment()
         mmm.StreamAttachments.Clear();
         mmm.StringAttachments.Clear();
 
-        using var stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(text ?? string.Empty));
+        using var stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(text));
         mmm.StreamAttachments.Add(new StreamAttachment(stream, streamAttFilename, "text/plain"));
 
         var msg = mmm.GetMimeMessage(dataItem);
@@ -291,7 +290,7 @@ public void ConvertHtmlToPlainText()
     [TestCase("{Name} {SenderAddr}", "John [email protected]")]
     [TestCase("{Name {SenderAddr}", "{Name {SenderAddr}")] // parsing error
     [TestCase("{NotExisting}", "{NotExisting}")] // formatting error
-    [TestCase(null, null)]
+    [TestCase("", "")]
     public void SearchAndReplace(string text, string expected)
     {
         var dataItem = new
@@ -310,7 +309,7 @@ public void SearchAndReplace(string text, string expected)
     [TestCase("{Name} {SenderAddr}", "John [email protected]")]
     [TestCase("{Name {SenderAddr}", "{Name {SenderAddr}")] // parsing error
     [TestCase("{NotExisting}", "{NotExisting}")] // formatting error
-    [TestCase(null, null)]
+    [TestCase("", "")]
     public void SearchAndReplaceFilename(string text, string expected)
     {
         var dataItem = new

Src/MailMergeLib.Tests/Message_Serialization.cs

@@ -2,7 +2,9 @@
 using System.IO;
 using System.Linq;
 using System.Text;
+using System.Xml.Linq;
 using MailMergeLib.Templates;
+using MimeKit;
 using NUnit.Framework;
 
 namespace MailMergeLib.Tests;

Src/MailMergeLib.Tests/Message_SmartFormatter.cs

@@ -58,7 +58,7 @@ public void PlaceholderCaseSensitivityTest()
     public void DataTypeTests()
     {
         // ******** Initialize ********
-        string result;
+        string? result;
         string expected;
         object dataItem;
         var culture = CultureInfo.GetCultureInfo("en-US");
@@ -171,7 +171,7 @@ public void DataTypeTests()
         catch (MailMergeMessage.MailMergeMessageException ex)
         {
             // will throw because of incomplete mail addresses, but Subject should contain placeholders replaced with content
-            result = ex.MimeMessage.Subject;
+            result = ex.MimeMessage?.Subject;
         }
 
         expected = text.Replace("{Email}", "[email protected]").Replace("{Continent}", "Europe");

Src/MailMergeLib.Tests/Message_Templates.cs

@@ -110,14 +110,10 @@ public void TemplateTest()
         });
         Assert.Throws<TemplateException>(() => t.Key = "This-is-definitely-an-illegal-Key-not-existing-in-any-Part");
 
-        Assert.False(t.Equals(null));
-        Assert.True(t.Equals(t));
         Assert.False(t.Equals(new object()));
 
         // Equality with null members
-        t.Name = t.Key = t.DefaultKey = null;
-        Assert.False(t.Equals(null));
-        Assert.True(t.Equals(t));
+        t.Key = t.DefaultKey = null;
         Assert.False(t.Equals(new object()));
     }
 }

Src/MailMergeLib.Tests/Message_VariableExceptions.cs

@@ -46,22 +46,22 @@ public void MissingVariableAndAttachmentsExceptions()
             foreach (var ex in exceptions.InnerExceptions.Where(ex => !(ex is MailMergeMessage
                          .AttachmentException)))
             {
-                if (ex is MailMergeMessage.VariableException)
+                if (ex is MailMergeMessage.VariableException exception)
                 {
-                    Assert.AreEqual(9, (ex as MailMergeMessage.VariableException).MissingVariable.Count);
+                    Assert.AreEqual(9, exception.MissingVariable.Count);
                     Console.WriteLine($"{nameof(MailMergeMessage.VariableException)} thrown successfully:");
                     Console.WriteLine("Missing variables: " +
                                       string.Join(", ",
-                                          (ex as MailMergeMessage.VariableException).MissingVariable));
+                                          exception.MissingVariable));
                     Console.WriteLine();
                 }
-                if (ex is MailMergeMessage.AddressException)
+                if (ex is MailMergeMessage.AddressException addressException)
                 {
                     Console.WriteLine($"{nameof(MailMergeMessage.AddressException)} thrown successfully:");
-                    Console.WriteLine((ex as MailMergeMessage.AddressException).Message);
+                    Console.WriteLine(addressException.Message);
                     Console.WriteLine();
-                    Assert.That((ex as MailMergeMessage.AddressException).Message == "No recipients." ||
-                                (ex as MailMergeMessage.AddressException).Message == "No from address.");
+                    Assert.That(addressException.Message == "No recipients." ||
+                                addressException.Message == "No from address.");
                 }
             }
 
@@ -73,9 +73,9 @@ public void MissingVariableAndAttachmentsExceptions()
             {
                 Console.WriteLine($"{nameof(MailMergeMessage.AttachmentException)} thrown successfully:");
                 Console.WriteLine("Missing files: " +
-                                  string.Join(", ", (ex as MailMergeMessage.AttachmentException).BadAttachment));
+                                  string.Join(", ", (ex as MailMergeMessage.AttachmentException)?.BadAttachment!));
                 Console.WriteLine();
-                Assert.AreEqual(1, (ex as MailMergeMessage.AttachmentException).BadAttachment.Count);
+                Assert.AreEqual(1, (ex as MailMergeMessage.AttachmentException)?.BadAttachment.Count);
             }
         }