diff --git a/flytestdlib/fastcheck/iface.go b/flytestdlib/fastcheck/iface.go
index e9d0637ad7..2c285b9b88 100644
--- a/flytestdlib/fastcheck/iface.go
+++ b/flytestdlib/fastcheck/iface.go
@@ -12,6 +12,9 @@ import (
 // For example an LRU cache, may have an overhead because of the use of a HashMap with loading factor and collision
 // resolution
 // The Data-structure is thread-safe and can be accessed by multiple threads concurrently.
+
+//go:generate mockery -name Filter -case=underscore
+
 type Filter interface {
 	// Contains returns a True if the id was previously seen or false otherwise
 	// It may return a false, even if a item may have previously occurred.
diff --git a/flytestdlib/fastcheck/mocks/filter.go b/flytestdlib/fastcheck/mocks/filter.go
new file mode 100644
index 0000000000..04b31555a8
--- /dev/null
+++ b/flytestdlib/fastcheck/mocks/filter.go
@@ -0,0 +1,78 @@
+// Code generated by mockery v1.0.1. DO NOT EDIT.
+
+package mocks
+
+import (
+	context "context"
+
+	mock "github.com/stretchr/testify/mock"
+)
+
+// Filter is an autogenerated mock type for the Filter type
+type Filter struct {
+	mock.Mock
+}
+
+type Filter_Add struct {
+	*mock.Call
+}
+
+func (_m Filter_Add) Return(evicted bool) *Filter_Add {
+	return &Filter_Add{Call: _m.Call.Return(evicted)}
+}
+
+func (_m *Filter) OnAdd(ctx context.Context, id []byte) *Filter_Add {
+	c := _m.On("Add", ctx, id)
+	return &Filter_Add{Call: c}
+}
+
+func (_m *Filter) OnAddMatch(matchers ...interface{}) *Filter_Add {
+	c := _m.On("Add", matchers...)
+	return &Filter_Add{Call: c}
+}
+
+// Add provides a mock function with given fields: ctx, id
+func (_m *Filter) Add(ctx context.Context, id []byte) bool {
+	ret := _m.Called(ctx, id)
+
+	var r0 bool
+	if rf, ok := ret.Get(0).(func(context.Context, []byte) bool); ok {
+		r0 = rf(ctx, id)
+	} else {
+		r0 = ret.Get(0).(bool)
+	}
+
+	return r0
+}
+
+type Filter_Contains struct {
+	*mock.Call
+}
+
+func (_m Filter_Contains) Return(_a0 bool) *Filter_Contains {
+	return &Filter_Contains{Call: _m.Call.Return(_a0)}
+}
+
+func (_m *Filter) OnContains(ctx context.Context, id []byte) *Filter_Contains {
+	c := _m.On("Contains", ctx, id)
+	return &Filter_Contains{Call: c}
+}
+
+func (_m *Filter) OnContainsMatch(matchers ...interface{}) *Filter_Contains {
+	c := _m.On("Contains", matchers...)
+	return &Filter_Contains{Call: c}
+}
+
+// Contains provides a mock function with given fields: ctx, id
+func (_m *Filter) Contains(ctx context.Context, id []byte) bool {
+	ret := _m.Called(ctx, id)
+
+	var r0 bool
+	if rf, ok := ret.Get(0).(func(context.Context, []byte) bool); ok {
+		r0 = rf(ctx, id)
+	} else {
+		r0 = ret.Get(0).(bool)
+	}
+
+	return r0
+}
diff --git a/flytestdlib/sets/generic_set_test.go b/flytestdlib/sets/generic_set_test.go
index 9d9f165ed5..ac95a64726 100644
--- a/flytestdlib/sets/generic_set_test.go
+++ b/flytestdlib/sets/generic_set_test.go
@@ -64,7 +64,15 @@ func TestGenericSet(t *testing.T) {
 		assert.True(t, g2.IsSuperset(g1))
 		assert.False(t, g1.IsSuperset(g2))
 	}
+	{
+		g1 := NewGeneric(GenericVal("a"), GenericVal("b"))
+		g2 := g1.UnsortedListKeys()
+		assert.Equal(t, g1.Len(), len(g2))
 
+		for _, key := range g2 {
+			assert.True(t, g1.Has(GenericVal(key)))
+		}
+	}
 	{
 		g1 := NewGeneric(GenericVal("a"), GenericVal("b"))
 		assert.True(t, g1.Has(GenericVal("a")))