tests: added exception unit tests

tests/Unit/ExceptionTests.cs

@@ -1,4 +1,5 @@
-using Minimig;
+using System;
+using Minimig;
 using MinimigTests.Fakes;
 using Xunit;
 
@@ -8,7 +9,7 @@ public class ExceptionTests
 {
     [Theory]
     [InlineData("SampleMigrations\\SqlServer\\0001 - Add One and Two tables.sql")]
-    public void Check_migration_exception(string filePath)
+    public void FakeMigration_ShouldHaveMigrationChangedException(string filePath)
     {
         //Arrange
         const string modified = "has been modified since it was run";
@@ -21,4 +22,43 @@ public void Check_migration_exception(string filePath)
         Assert.Contains(modified, exception.Message);
         Assert.Contains(mig.Filename, exception.Message);
     }
+
+    [Fact]
+    public void DefaultConstructor_ShouldHaveMessage()
+    {
+        // Arrange
+        const string message = "Exception of type 'Minimig.MigrationChangedException' was thrown.";
+
+        // Act
+        var exception = new MigrationChangedException();
+
+        // Assert
+        Assert.Equal(message, exception.Message);
+    }
+
+    [Theory]
+    [InlineData("Custom error message")]
+    public void Constructor_WithMessage_ShouldSetMessage(string message)
+    {
+        // Act
+        var exception = new MigrationChangedException(message);
+
+        // Assert
+        Assert.Equal(message, exception.Message);
+    }
+
+    [Theory]
+    [InlineData("Custom error message", "Inner exception message")]
+    public void Constructor_WithMessageAndInnerException_ShouldSetMessageAndInnerException(string message, string innerMessage)
+    {
+        // Arrange
+        var innerException = new Exception(innerMessage);
+
+        // Act
+        var exception = new MigrationChangedException(message, innerException);
+
+        // Assert
+        Assert.Equal(message, exception.Message);
+        Assert.Equal(innerException, exception.InnerException);
+    }
 }