Added test for not yet fixed issue

Author: JaBistDuNarrisch

src/Migrator.Tests/Providers/SQLServer/SQLServerTransformationProvider_ChangeColumnTests.cs

@@ -35,4 +35,22 @@ public void ChangeColumn_DateTimeToDateTime2_Success()
         Assert.That(columnBefore.Type == DbType.DateTime);
         Assert.That(columnAfter.Type == DbType.DateTime2);
     }
+
+    [Test, Ignore("This issue is not yet fixed. See https://github.com/dotnetprojects/Migrator.NET/issues/132")]
+    public void ChangeColumn_WithUniqueThenReChangeToNonUnique_UniqueConstraintShouldBeRemoved()
+    {
+        // Arrange
+        const string tableName = "TestTable";
+        const string columnName = "TestColumn";
+
+        Provider.AddTable(tableName, new Column(columnName, DbType.Int32, ColumnProperty.NotNull));
+
+        // Act
+        Provider.ChangeColumn(tableName, new Column(columnName, DbType.Int32, ColumnProperty.NotNull | ColumnProperty.Unique));
+        Provider.ChangeColumn(tableName, new Column(columnName, DbType.Int32, ColumnProperty.NotNull));
+
+        // Assert
+        var indexes = Provider.GetIndexes(tableName);
+        Assert.That(indexes, Is.Empty);
+    }
 }