diff --git a/ets2panda/test/ast/compiler/ets/method_overriding_conflict_no_override.ets b/ets2panda/test/ast/compiler/ets/method_overriding_conflict_no_override.ets
new file mode 100644
index 0000000000000000000000000000000000000000..ef1c14d8e3be4b555f57448793e103fcef507e12
--- /dev/null
+++ b/ets2panda/test/ast/compiler/ets/method_overriding_conflict_no_override.ets
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+interface L { foo(): string { return "L"; } }
+interface R { foo(): string { return "R"; } }
+
+class Bad implements L, R {}
+
+/* @@? 19:27 Error TypeError: Method 'foo' is declared in L and R interfaces. */
diff --git a/ets2panda/test/ast/compiler/ets/method_overriding_contravariant_return_type.ets b/ets2panda/test/ast/compiler/ets/method_overriding_contravariant_return_type.ets
new file mode 100644
index 0000000000000000000000000000000000000000..fe9ade6e628c309914510e238fa41d98375af31e
--- /dev/null
+++ b/ets2panda/test/ast/compiler/ets/method_overriding_contravariant_return_type.ets
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+interface Base { n(): int; }
+
+interface BadReturn extends Base {
+  n(): number;
+}
+
+/* @@? 19:4 Error TypeError: n(): double in BadReturn cannot override n(): int in Base because overriding return type is not compatible with the other return type. */
+/* @@? 19:4 Error TypeError: Method n(): double in BadReturn not overriding any method */
diff --git a/ets2panda/test/ast/compiler/ets/method_overriding_duplicate_declaration.ets b/ets2panda/test/ast/compiler/ets/method_overriding_duplicate_declaration.ets
new file mode 100644
index 0000000000000000000000000000000000000000..21d5ff0f03a736254870f4d42011073f0fc37bf5
--- /dev/null
+++ b/ets2panda/test/ast/compiler/ets/method_overriding_duplicate_declaration.ets
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+interface I { foo(): void; }
+
+class Duplicate implements I {
+  foo(): void {}
+  foo(): void {}
+}
+
+/* @@? 20:3 Error TypeError: Function foo is already declared. */