diff --git a/src/Avalonia.Base/Data/Core/UntypedBindingExpressionBase.cs b/src/Avalonia.Base/Data/Core/UntypedBindingExpressionBase.cs
index 4fc27fb639..ef6be2666f 100644
--- a/src/Avalonia.Base/Data/Core/UntypedBindingExpressionBase.cs
+++ b/src/Avalonia.Base/Data/Core/UntypedBindingExpressionBase.cs
@@ -238,26 +238,6 @@ public abstract class UntypedBindingExpressionBase : BindingExpressionBase,
         return o;
     }
 
-    /// <summary>
-    /// Produces an observable which can be used to observe the value of the binding expression
-    /// for unit testing.
-    /// </summary>
-    /// <param name="targetType">The <see cref="TargetType"/>.</param>
-    /// <returns>An observable subject.</returns>
-    /// <exception cref="InvalidOperationException">
-    /// The binding expression is already instantiated on an AvaloniaObject.
-    /// </exception>
-    /// <remarks>
-    /// This method should be considered obsolete and new unit tests should not be written to use
-    /// it. For more information see <see cref="ToObservable(AvaloniaObject?)"/>.
-    /// </remarks>
-    internal IAvaloniaSubject<object?> ToObservable(Type targetType)
-    {
-        var o = ToObservable(target: null);
-        TargetType = targetType;
-        return o;
-    }
-
     /// <summary>
     /// When overridden in a derived class, writes the specified value to the binding source if
     /// possible.
diff --git a/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs b/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs
index 71745e1855..daca14c014 100644
--- a/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs
+++ b/tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.cs
@@ -57,25 +57,6 @@ public abstract partial class BindingExpressionTests
             target.GetValueStore().AddBinding(targetProperty, bindingExpression);
             return (target, bindingExpression);
         }
-
-        private protected override BindingExpression CreateTargetLegacy<TIn, TOut>(
-            TIn data,
-            Expression<Func<TIn, TOut>> expression,
-            IValueConverter? converter = null,
-            object? converterParameter = null,
-            bool enableDataValidation = false,
-            Optional<object?> fallbackValue = default,
-            object? targetNullValue = null)
-        {
-            return BindingExpression.Create(
-                data,
-                expression,
-                converter: converter,
-                converterParameter: converterParameter,
-                enableDataValidation: enableDataValidation,
-                fallbackValue: fallbackValue.HasValue ? fallbackValue.Value : AvaloniaProperty.UnsetValue,
-                targetNullValue: targetNullValue);
-        }
     }
 
     public class Compiled : BindingExpressionTests
@@ -117,29 +98,6 @@ public abstract partial class BindingExpressionTests
             target.GetValueStore().AddBinding(targetProperty, bindingExpression);
             return (target, bindingExpression);
         }
-
-        private protected override BindingExpression CreateTargetLegacy<TIn, TOut>(
-            TIn data,
-            Expression<Func<TIn, TOut>> expression,
-            IValueConverter? converter = null,
-            object? converterParameter = null,
-            bool enableDataValidation = false,
-            Optional<object?> fallbackValue = default,
-            object? targetNullValue = null)
-        {
-            var nodes = new List<ExpressionNode>();
-            var path = CompiledBindingPathFromExpressionBuilder.Build(expression, enableDataValidation);
-            path.BuildExpression(nodes, out var _);
-            return new BindingExpression(
-                data,
-                nodes,
-                converter: converter,
-                converterParameter: converterParameter,
-                enableDataValidation: enableDataValidation,
-                fallbackValue: fallbackValue.HasValue ? fallbackValue.Value : AvaloniaProperty.UnsetValue,
-                targetNullValue: targetNullValue,
-                targetTypeConverter: TargetTypeConverter.GetDefaultConverter());
-        }
     }
 
     protected TargetClass CreateTarget<TIn, TOut>(
@@ -248,16 +206,6 @@ public abstract partial class BindingExpressionTests
         UpdateSourceTrigger updateSourceTrigger)
             where TIn : class?;
 
-    private protected abstract BindingExpression CreateTargetLegacy<TIn, TOut>(
-        TIn data,
-        Expression<Func<TIn, TOut>> expression,
-        IValueConverter? converter = null,
-        object? converterParameter = null,
-        bool enableDataValidation = false,
-        Optional<object?> fallbackValue = default,
-        object? targetNullValue = null)
-            where TIn : class?;
-
     private static IDisposable StartWithFocusSupport()
     {
         return UnitTestApplication.Start(TestServices.RealFocus);