//go:build linux

package cluster

import "testing"

// TestSampleNetLoadBasic: the sampler must stay in [0,100], must return 0 on
// the first (seeding) call, and must be stable across repeated calls. On a
// CI/dev box without a speed-known physical NIC it may legitimately return 0
// every time — that's fine; we only assert the invariants, not a specific
// value.
func TestSampleNetLoadBasic(t *testing.T) {
	first := SampleNetLoad()
	if first < 0 || first > 100 {
		t.Fatalf("first sample out of range: %v", first)
	}
	for i := 0; i < 3; i++ {
		v := SampleNetLoad()
		if v < 0 || v > 100 {
			t.Fatalf("sample %d out of range: %v", i, v)
		}
	}
}

// TestIsPhysicalUplink: virtual/container interfaces must never count as
// uplinks — a busy docker bridge would otherwise fake host saturation.
func TestIsPhysicalUplink(t *testing.T) {
	cases := []struct {
		name string
		typ  int
		want bool
	}{
		{"lo", 772, false},
		{"ens18", 1, true}, // ARPHRD_ETHER physical
		{"eth0", 1, true},  // ARPHRD_ETHER physical
		{"docker0", 1, false},
		{"br-abc123", 1, false},
		{"veth9f2c1a", 1, false},
		{"wg0", 1, false},
		{"tun0", 65534, false}, // ARPHRD_NONE software iface
		{"tap7", 1, false},
		{"bond0", 1, true}, // real aggregated uplink counts
	}
	for _, c := range cases {
		if got := isPhysicalUplink(c.name, c.typ); got != c.want {
			t.Errorf("isPhysicalUplink(%q,%d)=%v want %v", c.name, c.typ, got, c.want)
		}
	}
}