feat(*): Update readme with exception extensions

Creek.HelpfulExtensions/Creek.HelpfulExtensions.csproj

@@ -19,8 +19,8 @@
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
     <RepositoryType>git</RepositoryType>
     <PackageTags>creek</PackageTags>
-    <Version>1.1.0</Version>
-    <AssemblyVersion>1.1.0.0</AssemblyVersion>
+    <Version>1.3.0</Version>
+    <AssemblyVersion>1.3.0.0</AssemblyVersion>
   </PropertyGroup>
 
   <ItemGroup>

Creek.HelpfulExtensions/ExceptionExtension.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Creek.HelpfulExtensions
+{
+    public static class ExceptionExtension
+    {
+        /// <summary>
+        /// Returns a string of the message of the first/root/base exception in an exception stack.
+        /// </summary>
+        /// <param name="ex">The Exception stack to find the first/root/base exception within.</param>
+        /// <returns>Returns the first/root/base exception message string.</returns>
+        public static string BaseExceptionMessage(this Exception ex)
+        {
+            Exception baseEx = ex.GetBaseException();
+            return baseEx.Message;
+        }
+
+        /// <summary>
+        /// Returns a single string of the message and stack trace of the first/root/base exception in an exception stack.
+        /// </summary>
+        /// <param name="ex">The Exception stack to find the first/root/base exception within.</param>
+        /// <returns>Returns the first/root/base exception message and stack trace as a single string, separated by " :: ".</returns>
+        public static string BaseExceptionMessageAndStackTrace(this Exception ex)
+        {
+            Exception baseEx = ex.GetBaseException();
+            return GenerateMessageAndStackTraceString(baseEx);
+        }
+
+        /// <summary>
+        /// Returns a list of the exception messages of each nested exception in an exception stack.
+        /// </summary>
+        /// <param name="ex">The Exception stack.</param>
+        /// <returns>Returns a list of the exception messages of each nested exception in an exception stack.</returns>
+        public static List<string> AllInnerExceptionMessages(this Exception ex)
+        {
+            return GetAllInnerExceptionMessagesAndStackTraces(ex, includeStackTraces: false);
+        }
+
+        /// <summary>
+        /// Returns a list of single strings of the message and stack trace of each nested exception in an exception stack.
+        /// </summary>
+        /// <param name="ex">The Exception stack.</param>
+        /// <returns>Returns a list with a string for each nested exception in an exception stack containing the exception message and stack trace as a single string, separated by " :: ".</returns>
+        public static List<string> AllInnerExceptionMessagesAndStackTraces(this Exception ex)
+        {
+            return GetAllInnerExceptionMessagesAndStackTraces(ex, includeStackTraces: true);
+        }
+
+        private static List<string> GetAllInnerExceptionMessagesAndStackTraces(Exception ex, bool includeStackTraces)
+        {
+            List<string> exceptionMessagesAndStackTraces = new List<string>();
+
+            Exception inner = ex.InnerException;
+
+            exceptionMessagesAndStackTraces.Add(
+                includeStackTraces ? GenerateMessageAndStackTraceString(ex)
+                : ex.Message);
+
+            while (inner != null)
+            {
+                exceptionMessagesAndStackTraces.Add(
+                includeStackTraces ? GenerateMessageAndStackTraceString(inner)
+                : inner.Message);
+                inner = inner.InnerException;
+            }
+
+            // We've now reached the end of the exceptions, so can return the error messages
+            return exceptionMessagesAndStackTraces;
+        }
+
+        private static string GenerateMessageAndStackTraceString(Exception ex)
+        {
+            return $"{ex.Message} :: {ex.StackTrace}";
+        }
+    }
+}

Creek.HelpfulExtensions/SystemTime.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Creek.HelpfulExtensions
+{
+    public static class SystemTime
+    {
+        /// <summary>
+        /// This method exposes DateTime.Now as an instance of a function, that can be replaced in tests.
+        /// </summary>
+#pragma warning disable S1104 // Fields should not have public accessibility
+#pragma warning disable S2223 // Non-constant static fields should not be visible
+        public static Func<DateTime> Now = () => DateTime.Now;
+#pragma warning restore S2223 // Non-constant static fields should not be visible
+#pragma warning restore S1104 // Fields should not have public accessibility
+    }
+}

README.md

@@ -40,3 +40,97 @@ foreach (var (item, index) in list.WithIndex())
     // ...
 }
 ```
+
+## DateTime Extensions
+
+### SystemTime.Now
+
+This is technically not an extension, but fits well in this package. It's taken from [this blog](https://lostechies.com/jimmybogard/2008/11/09/systemtime-versus-isystemclock-dependencies-revisited/). This method exposes DateTime.Now as an instance of a function, that can be replaced in tests.
+
+If you want to replace SystemTime.Now in a test you can do it like this:
+
+```csharp
+[Test]
+public void Should_test_something_here()
+{
+    var systemTimeDate = new DateTime(2021, 9, 2);
+    SystemTime.Now = () => new DateTime(2021, 9, 2);
+
+    DateTime dateTimeToBeTested = systemTimeDate;
+
+    // ...
+}
+```
+
+You can also set SystemTime.Now to any function that returns a DateTime:
+
+```csharp
+var startDate = new DateTime(2021, 9, 2);
+SystemTime.Now = () => startDate.AddDays(2);
+```
+
+## Exception Extensions
+
+### BaseExceptionMessage
+
+Returns a string of the message of the first/root/base exception in an exception stack.
+
+```csharp
+try
+{
+    ...
+}
+catch (Exception ex)
+{
+    string baseExceptionMessage = ex.BaseExceptionMessage();
+    ...
+}
+```
+
+### BaseExceptionMessageAndStackTrace
+
+Returns a single string of the message and stack trace of the first/root/base exception in an exception stack.
+
+```csharp
+try
+{
+    ...
+}
+catch (Exception ex)
+{
+    string baseExceptionMessageAndStackTrace = ex.BaseExceptionMessageAndStackTrace();
+    ...
+}
+```
+
+### AllInnerExceptionMessages
+
+Returns a list of the exception messages of each nested exception in an exception stack.
+
+```csharp
+try
+{
+    ...
+}
+catch (Exception ex)
+{
+    List<string> allInnerExceptionMessages = ex.AllInnerExceptionMessages();
+    ...
+}
+```
+
+### AllInnerExceptionMessagesAndStackTraces
+
+Returns a list of single strings of the message and stack trace of each nested exception in an exception stack.
+
+```csharp
+try
+{
+    ...
+}
+catch (Exception ex)
+{
+    List<string> allInnerExceptionMessagesAndStackTraces = ex.AllInnerExceptionMessagesAndStackTraces();
+    ...
+}
+```

UnitTests/ExceptionExtensionTests.cs

@@ -0,0 +1,144 @@
+using NUnit.Framework;
+using Creek.HelpfulExtensions;
+using System;
+using System.Collections.Generic;
+
+namespace UnitTests
+{
+    public class ExceptionExtensionTests
+    {
+        [SetUp]
+        public void Setup()
+        {
+        }
+
+        [Test]
+        public void ShouldReturnBaseExceptionMessage()
+        {
+            try
+            {
+                // This function calls another that forces a
+                // division by 0.
+                Rethrow();
+            }
+            catch (Exception ex)
+            {
+                string baseExceptionMessage = ex.BaseExceptionMessage();
+                Assert.AreEqual("Attempted to divide by zero.", baseExceptionMessage);
+            }
+        }
+
+        [Test]
+        public void ShouldReturnBaseExceptionMessageAndStackTrace()
+        {
+            try
+            {
+                // This function calls another that forces a
+                // division by 0.
+                Rethrow();
+            }
+            catch (Exception ex)
+            {
+                string baseExceptionMessageAndStackTrace = ex.BaseExceptionMessageAndStackTrace();
+                StringAssert.StartsWith("Attempted to divide by zero.", baseExceptionMessageAndStackTrace);
+                Assert.AreNotEqual("Attempted to divide by zero.", baseExceptionMessageAndStackTrace);
+            }
+        }
+
+        [Test]
+        public void ShouldReturnAllInnerExceptionMessages()
+        {
+            try
+            {
+                // This function calls another that forces a
+                // division by 0.
+                Rethrow();
+            }
+            catch (Exception ex)
+            {
+                List<string> allInnerExceptionMessages = ex.AllInnerExceptionMessages();
+
+                List<string> expected = new List<string>()
+                {
+                    "Caught the second exception and threw a third in response.",
+                    "Forced a division by 0 and threw a second exception.",
+                    "Attempted to divide by zero.",
+                };
+
+                CollectionAssert.AreEqual(expected, allInnerExceptionMessages);
+            }
+        }
+
+        [Test]
+        public void ShouldReturnAllInnerExceptionMessagesAndStackTraces()
+        {
+            try
+            {
+                // This function calls another that forces a
+                // division by 0.
+                Rethrow();
+            }
+            catch (Exception ex)
+            {
+                List<string> allInnerExceptionMessagesAndStackTraces = ex.AllInnerExceptionMessagesAndStackTraces();
+
+                List<string> expected = new List<string>()
+                {
+                    "Caught the second exception and threw a third in response.",
+                    "Forced a division by 0 and threw a second exception.",
+                    "Attempted to divide by zero.",
+                };
+
+                foreach (var (baseExceptionMessageAndStackTrace, index) in allInnerExceptionMessagesAndStackTraces.WithIndex())
+                {
+                    StringAssert.StartsWith(expected[index], baseExceptionMessageAndStackTrace);
+                    Assert.AreNotEqual(expected[index], baseExceptionMessageAndStackTrace);
+                }
+            }
+        }
+
+        // This function catches the exception from the called
+        // function DivideBy0( ) and throws another in response.
+        private void Rethrow()
+        {
+            try
+            {
+                DivideBy0();
+            }
+            catch (Exception ex)
+            {
+                throw new ThirdLevelException("Caught the second exception and threw a third in response.", ex);
+            }
+        }
+
+        // This function forces a division by 0 and throws a second
+        // exception.
+        private void DivideBy0()
+        {
+            try
+            {
+                int zero = 0;
+                int ecks = 1 / zero;
+            }
+            catch (Exception ex)
+            {
+                throw new SecondLevelException("Forced a division by 0 and threw a second exception.", ex);
+            }
+        }
+
+        // Define two derived exceptions to demonstrate nested exceptions.
+        private class SecondLevelException : Exception
+        {
+            public SecondLevelException(string message, Exception inner)
+                : base(message, inner)
+            { }
+        }
+
+        private class ThirdLevelException : Exception
+        {
+            public ThirdLevelException(string message, Exception inner)
+                : base(message, inner)
+            { }
+        }
+    }
+}