diff --git a/LanguageFeatures/Augmentations/augmenting_constructors_A05_t02.dart b/LanguageFeatures/Augmentations/augmenting_constructors_A05_t02.dart
new file mode 100644
index 0000000000..20eabc32c3
--- /dev/null
+++ b/LanguageFeatures/Augmentations/augmenting_constructors_A05_t02.dart
@@ -0,0 +1,56 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion It is a compile-time error if:
+/// ...
+/// - The augmentation chain has exactly one specification of a default value
+///   for an optional parameter, and the constructor is a redirecting factory.
+///
+/// @description Checks that it is a compile-time error if the augmentation
+/// chain has exactly one specification of a default value for an optional
+/// parameter, but the constructor is a redirecting factory.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=augmentations
+
+class C {
+  C([int x = 0]);
+  C._({int x = 0});
+  factory C.foo([int x]) = C;
+  factory C.bar({int x}) = C._;
+}
+
+augment class C {
+  augment factory C.foo([int x = 0]);
+//                ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  augment factory C.bar({int x = 0});
+//                ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET(int x) {
+  ET.c1([this.x = 0]);
+  ET.c2({this.x = 0});
+  factory ET.foo([int x]) = ET.c1;
+  factory ET.bar({int x}) = ET.c2;
+}
+
+augment extension type ET {
+  augment ET.foo([int x = 0]);
+//        ^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  augment ET.bar({int x = 0});
+//        ^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(ET);
+}
diff --git a/LanguageFeatures/Augmentations/augmenting_constructors_A06_t01.dart b/LanguageFeatures/Augmentations/augmenting_constructors_A06_t01.dart
new file mode 100644
index 0000000000..7cbac04e9e
--- /dev/null
+++ b/LanguageFeatures/Augmentations/augmenting_constructors_A06_t01.dart
@@ -0,0 +1,124 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion It is a compile-time error if:
+/// ...
+/// - No declaration in the augmentation chain specifies a default value for an
+///   optional parameter whose declared type is potentially non-nullable, and
+///   the constructor is not a redirecting factory.
+///
+/// @description Checks that it is a compile-time error if no declaration in the
+/// augmentation chain specifies a default value for an optional parameter whose
+/// declared type is potentially non-nullable, and the constructor is not a
+/// redirecting factory.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=augmentations
+
+class C {
+  C(int x);
+  C.c1([int x]);
+//          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  C.c2({int x});
+//          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  C.c3([int x]) : this(x);
+//          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  C.c4({int x}) : this(x);
+//          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory C.c5([int x]) => C(x);
+//                  ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory C.c6({int x}) => C(x);
+//                  ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment class C {
+  augment C.c1([int x]) {}
+  augment C.c2({int x}) {}
+  augment C.c3([int x]);
+  augment C.c4({int x});
+  augment factory C.c5([int x]);
+  augment factory C.c6({int x});
+}
+
+enum E {
+  e0(0);
+
+  const E(int x);
+  const E.c1([int x]);
+//                ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  const E.c2({int x});
+//                ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  const E.c3([int x]) : this(x);
+//                ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  const E.c4({int x}) : this(x);
+//                ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment enum E {
+  augment const E.c1([int x]) {}
+  augment const E.c2({int x}) {}
+  augment const E.c3([int x]);
+  augment const E.c4({int x});
+}
+
+extension type ET(int x) {
+  ET.c1([this.x]);
+//            ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  ET.c2({this.x});
+//            ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  ET.c3([int x]) : this(x);
+//           ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  ET.c4({int x}) : this(x);
+//           ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory ET.c5([int x]) => ET(x);
+//                   ^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory ET.c6({int x}) => ET(x);
+//                   ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension type ET {
+  augment ET.c1([this.x]) {}
+  augment ET.c2({this.x}) {}
+  augment ET.c3([int x]);
+  augment ET.c4({int x});
+  augment factory ET.c5([int x]);
+  augment factory ET.c6({int x});
+}
+
+main() {
+  print(C);
+  print(ET);
+}
diff --git a/LanguageFeatures/Augmentations/augmenting_constructors_A07_t01.dart b/LanguageFeatures/Augmentations/augmenting_constructors_A07_t01.dart
new file mode 100644
index 0000000000..636b0473b9
--- /dev/null
+++ b/LanguageFeatures/Augmentations/augmenting_constructors_A07_t01.dart
@@ -0,0 +1,61 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion It is a compile-time error if:
+/// ...
+/// - A factory constructor is incomplete after all augmentations are applied.
+///
+/// @description Checks that it is a compile-time error if a factory constructor
+/// is incomplete after all augmentations are applied.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=augmentations
+
+class C {
+  C(int x);
+  factory C.f1();
+//        ^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory C.f2([int x]);
+//        ^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory C.f3({int x});
+//        ^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment class C {
+  augment factory C.f1();
+  augment factory C.f2([int x = 0]);
+  augment factory C.f3({int x = 0});
+}
+
+extension type ET(int x) {
+  factory ET.f1();
+//        ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory ET.f2([int x]);
+//        ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  factory ET.f3({int x});
+//        ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension type ET {
+  augment factory ET.f1();
+  augment factory ET.f2([int x = 0]);
+  augment factory ET.f3({int x = 0});
+}
+
+main() {
+  print(C);
+  print(ET);
+}