Moved system package inputs out to top level (#4406)

plugins/inputs/swap/swap_test.go

@@ -0,0 +1,39 @@
+package swap
+
+import (
+	"testing"
+
+	"github.com/influxdata/telegraf/plugins/inputs/system"
+	"github.com/influxdata/telegraf/testutil"
+	"github.com/shirou/gopsutil/mem"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSwapStats(t *testing.T) {
+	var mps system.MockPS
+	var err error
+	defer mps.AssertExpectations(t)
+	var acc testutil.Accumulator
+
+	sms := &mem.SwapMemoryStat{
+		Total:       8123,
+		Used:        1232,
+		Free:        6412,
+		UsedPercent: 12.2,
+		Sin:         7,
+		Sout:        830,
+	}
+
+	mps.On("SwapStat").Return(sms, nil)
+
+	err = (&SwapStats{&mps}).Gather(&acc)
+	require.NoError(t, err)
+
+	swapfields := map[string]interface{}{
+		"total":        uint64(8123),
+		"used":         uint64(1232),
+		"used_percent": float64(12.2),
+		"free":         uint64(6412),
+	}
+	acc.AssertContainsTaggedFields(t, "swap", swapfields, make(map[string]string))
+}