rapl-daemon/util_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"io/ioutil"
+	"log"
 	"math"
 	"os"
 	"path/filepath"
@@ -12,65 +13,67 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var raplDir string
+
+const maxWattage uint64 = 1500000
+
+func TestMain(m *testing.M) {
+	var err error
+	raplDir, err = ioutil.TempDir("", raplPrefixCPU)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer os.RemoveAll(raplDir)
+
+	// Create temporary directory that mocks powercap subsytem
+	zonePath := filepath.Join(raplDir, raplPrefixCPU+":0")
+	err = os.Mkdir(zonePath, 755)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	initialWatts := strconv.FormatUint(maxWattage, 10)
+
+	err = ioutil.WriteFile(filepath.Join(zonePath, maxPowerFileShortWindow), []byte(initialWatts), 0444)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = ioutil.WriteFile(filepath.Join(zonePath, powerLimitFileShortWindow), []byte(initialWatts), 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	os.Exit(m.Run())
+}
+
 // TODO(rdelvalle): Create filesystem only once and allow tests to use it
 func TestCapNode(t *testing.T) {
-
-	RAPLdir, err := ioutil.TempDir("", "intel-rapl")
-	assert.NoError(t, err)
-	defer os.RemoveAll(RAPLdir)
-
-	zonePath := filepath.Join(RAPLdir, raplPrefixCPU+":0")
-	err = os.Mkdir(zonePath, 755)
-	assert.NoError(t, err)
-	err = ioutil.WriteFile(filepath.Join(zonePath, maxPowerFileShortWindow), []byte("1500000"), 0444)
-	assert.NoError(t, err)
-	err = ioutil.WriteFile(filepath.Join(zonePath, powerLimitFileShortWindow), []byte("1500000"), 0644)
-	assert.NoError(t, err)
-
-	err = capNode(RAPLdir, 95)
+	err := capNode(raplDir, 95)
 	assert.NoError(t, err)
 }
 
 func TestMaxPower(t *testing.T) {
-	const maxWattage uint64 = 1500000
+	maxFile := filepath.Join(raplDir, raplPrefixCPU+":0", maxPowerFileShortWindow)
 
-	tmpfile, err := ioutil.TempFile("", maxPowerFileShortWindow)
-	assert.NoError(t, err)
-
-	defer os.Remove(tmpfile.Name())
-
-	_, err = tmpfile.Write([]byte(strconv.FormatUint(maxWattage, 10)))
-	assert.NoError(t, err)
-
-	maxWatts, err := maxPower(tmpfile.Name())
+	maxWatts, err := maxPower(maxFile)
 	assert.NoError(t, err)
 	assert.Equal(t, maxWattage, maxWatts)
-
-	err = tmpfile.Close()
-	assert.NoError(t, err)
 }
 
 func TestCapZone(t *testing.T) {
-	const maxPower float64 = 1500000
 	const percentage float64 = .50
 
-	tmpfile, err := ioutil.TempFile("", powerLimitFileShortWindow)
+	powercap := uint64(math.Ceil(float64(maxWattage) * percentage))
+	limitFile := filepath.Join(raplDir, raplPrefixCPU+":0", powerLimitFileShortWindow)
+	err := capZone(limitFile, powercap)
 	assert.NoError(t, err)
 
-	defer os.Remove(tmpfile.Name())
-
-	powercap := uint64(math.Ceil(maxPower * percentage))
-
-	err = capZone(tmpfile.Name(), powercap)
-	assert.NoError(t, err)
-
-	newCapBytes, err := ioutil.ReadFile(tmpfile.Name())
+	newCapBytes, err := ioutil.ReadFile(limitFile)
 	assert.NoError(t, err)
 
 	newCap, err := strconv.ParseUint(strings.TrimSpace(string(newCapBytes)), 10, 64)
 	assert.NoError(t, err)
 	assert.Equal(t, powercap, newCap)
-
-	err = tmpfile.Close()
-	assert.NoError(t, err)
 }