chore: add more tests (#3259)

core/stat/internal/cgroup_linux_test.go

@@ -0,0 +1,12 @@
+package internal
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRunningInUserNS(t *testing.T) {
+	// should be false in docker
+	assert.False(t, runningInUserNS())
+}