diff --git a/tests/cases/fourslash/codeFixClassExtendsAbstractFunction.ts b/tests/cases/fourslash/codeFixClassExtendsAbstractFunction.ts
new file mode 100644
index 00000000000..6bed7a3fe0f
--- /dev/null
+++ b/tests/cases/fourslash/codeFixClassExtendsAbstractFunction.ts
@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// abstract class A {
+////    abstract f();
+//// }
+////
+//// class C extends A {[|
+//// |]}
+
+verify.codeFixAtPosition(`f(){
+    throw new Error('Method not Implemented');
+}
+`);
\ No newline at end of file
diff --git a/tests/cases/fourslash/codeFixClassExtendsAbstractProtectedNumber.ts b/tests/cases/fourslash/codeFixClassExtendsAbstractProtectedNumber.ts
new file mode 100644
index 00000000000..7f525632fc5
--- /dev/null
+++ b/tests/cases/fourslash/codeFixClassExtendsAbstractProtectedNumber.ts
@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+//// abstract class A {
+////    protected abstract x: number;
+//// }
+////
+//// class C extends A {[|
+//// |]}
+
+verify.codeFixAtPosition(`protected x: number;
+`);
diff --git a/tests/cases/fourslash/codeFixClassExtendsAbstractPublicNumber.ts b/tests/cases/fourslash/codeFixClassExtendsAbstractPublicNumber.ts
new file mode 100644
index 00000000000..82cafbd86ad
--- /dev/null
+++ b/tests/cases/fourslash/codeFixClassExtendsAbstractPublicNumber.ts
@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+//// abstract class A {
+////    public abstract x: number;
+//// }
+////
+//// class C extends A {[|
+//// |]}
+
+verify.codeFixAtPosition(`public x: number;
+`);
\ No newline at end of file
diff --git a/tests/cases/fourslash/codeFixInterfaceInExtendsClause.ts b/tests/cases/fourslash/codeFixInterfaceInExtendsClause.ts
new file mode 100644
index 00000000000..c08cdc30952
--- /dev/null
+++ b/tests/cases/fourslash/codeFixInterfaceInExtendsClause.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts' />
+
+//// interface I {
+////    f1();
+//// }
+////
+//// class /*0*/C/*1*/ /*2*/extend/*3*/s/*4*/ /*5*/I/*6*/ {/*7*/}
+
+for (let i = 0; i < 8; ++i) {
+    goTo.marker("" + i);
+    verify.codeFixAtPosition("");
+}
\ No newline at end of file
diff --git a/tests/cases/fourslash/codeFixUnimplementedInterfaceMissingMultipleFunctions.ts b/tests/cases/fourslash/codeFixUnimplementedInterfaceMissingMultipleFunctions.ts
new file mode 100644
index 00000000000..02415491191
--- /dev/null
+++ b/tests/cases/fourslash/codeFixUnimplementedInterfaceMissingMultipleFunctions.ts
@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts' />
+
+//// class C1 {
+////     f1();
+//// }
+////
+//// class C2 {
+////     f2();
+//// }
+////
+//// interface I1 extends C1, C2 {}
+////
+//// class C3 implements I1 {[|
+//// |]}
+
+verify.codeFixAtPosition(`f1(){
+    throw new Error('Method not Implemented');
+}
+f2(){
+    throw new Error('Method not Implemented');
+}
+`);
\ No newline at end of file
diff --git a/tests/cases/fourslash/codeFixUnimplementedInterfaceMissingMultipleFunctionsDeepInheritance.ts b/tests/cases/fourslash/codeFixUnimplementedInterfaceMissingMultipleFunctionsDeepInheritance.ts
new file mode 100644
index 00000000000..729df3a91c8
--- /dev/null
+++ b/tests/cases/fourslash/codeFixUnimplementedInterfaceMissingMultipleFunctionsDeepInheritance.ts
@@ -0,0 +1,62 @@
+/// <reference path='fourslash.ts' />
+
+
+//// // Referenced throughout the inheritance chain.
+//// interface I0 { a: number }
+//// 
+//// class C1 implements I0 { a: number }
+//// interface I1 { b: number }
+//// interface I2 extends C1, I1 {}
+//// 
+//// class C2 { c: number }
+//// interface I3 {d: number}
+//// class C3 extends C2 implements I0, I2, I3 {
+////     a: number;
+////     b: number;
+////     d: number;
+//// }
+//// 
+//// interface I4 { e: number }
+//// interface I5 { f: number }
+//// class C4 extends C3 implements I0, I4, I5 {
+////     e: number;
+////     f: number;
+//// }
+//// 
+//// interface I6 extends C4 {}
+//// class C5 implements I6 {[|
+//// |]}
+
+
+/**
+ * We want to check whether the search for member to replace actually searches through
+ * the various possible paths of the inheritance chain correctly, and that We
+ * don't issue duplicates for the same member.
+ * 
+ * Our class DAG:
+ * 
+ * C5
+ * |-I6
+ *   |-C4
+ *     |-I4
+ *     |-I5
+ *     |------------------------ I0
+ *     |-C3
+ *       |-I2
+ *         |-I1
+ *         |-C1
+ *           |-------------------I0
+ *       |-I3
+ *       |-----------------------I0
+ *       |-C2
+ */
+
+
+verify.codeFixAtPosition(
+`a: number;
+b: number;
+c: number;
+d: number;
+e: number:
+f: number;
+`);