I'm trying to write a controller and I'm having a few issues writing tests.

I've used some code from the k8s HPA in my controller and I'm seeing something weird when using the testrestmapper.

basically when running this test with a breakpoint here I see the mappings are returned.

When I do the same the mappings are not returned.

What magic is happening here?

The following test fails

package main

import (
    "github.com/stretchr/testify/assert"
    "k8s.io/apimachinery/pkg/api/meta/testrestmapper"
    "k8s.io/apimachinery/pkg/runtime/schema"
    "k8s.io/kubernetes/pkg/api/legacyscheme"
    "testing"
)

func TestT(t *testing.T) {
    mapper := testrestmapper.TestOnlyStaticRESTMapper(legacyscheme.Scheme)

    gk := schema.FromAPIVersionAndKind("apps/v1", "Deployment").GroupKind()
    mapping, err := mapper.RESTMapping(gk)

    assert.NoError(t, err)
    assert.NotNil(t, mapping)
}