You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: store_test.go
    path of file: ./repos/beam/sdks/go/pkg/beam/core/metrics
    
    the code of the file until where you have to start completion: // Licensed to the Apache Software Foundation (ASF) 
    
func TestStore(t *testing.T) {
	store := newStore()

	m := make(map[Labels]any)
	e := &Extractor{
		SumInt64: func(l Labels, v int64) {
			m[l] = &counter{value: v}
		},
		DistributionInt64: func(l Labels, count, sum, min, max int64) {
			m[l] = &distribution{count: count, sum: sum, min: min, max: max}
		},
		GaugeInt64: func(l Labels, v int64, t time.Time) {
			m[l] = &gauge{v: v, t: t}
		},
		MsecsInt64: func(labels string, e *[4]ExecutionState) {},
	}

	now := time.Now()

	store.storeMetric("pid", newName("ns", "counter"), &counter{value: 1})
	store.storeMetric("pid", newName("ns", "distribution"), &distribution{count: 1, sum: 2, min: 3, max: 4})
	store.storeMetric("pid", newName("ns", "gauge"), &gauge{v: 1, t: now})

	// storing the same metric twice doesn't change anything
	store.storeMetric("pid", newName("ns", "counter"), &counter{value: 2})

	err := e.ExtractFrom(store)
	if err != nil {
		t.Fatalf("e.ExtractFrom(store) = %q, want nil", err)
	}

	expected := map[Labels]any{
		{transform: "pid", namespace: "ns", name: "counter"}:      &counter{value: 1},
		{transform: "pid", namespace: "ns", name: "distribution"}: &distribution{count: 1, sum: 2, min: 3, max: 4},
		{transform: "pid", namespace: "ns", name: "gauge"}:        &gauge{v: 1, t: now},
	}
	if !reflect.DeepEqual(m, expected) {
		t.Errorf("e.ExtractFrom(store) = %v, want %v", m, expected)
	}
}