diff --git a/testing/coverage/coverall b/testing/coverage/coverall
index 5aa3823e2..7d0457308 100755
--- a/testing/coverage/coverall
+++ b/testing/coverage/coverall
@@ -1,19 +1,22 @@
 #!/bin/bash
 
 FAIL=0
-COVERAGE_FILE=coverage.txt
+
+V2RAY_OUT=${GOPATH}/out/v2ray
+V2RAY_COV=${V2RAY_OUT}/cov
+COVERAGE_FILE=${V2RAY_COV}/coverage.txt
 
 function test_package {
   DIR="github.com/v2ray/v2ray-core/$1"
   DEP=$(go list -f '{{ join .Deps "\n" }}' $DIR | grep v2ray | tr '\n' ',')
   DEP=${DEP}$DIR
-  go test -tags "json coverage" -coverprofile=coversingle.out -coverpkg=$DEP $DIR || FAIL=1
-  if [ -f coversingle.out ]; then
-    cat coversingle.out | grep -v "mode: set" >> ${COVERAGE_FILE}
-    rm coversingle.out
-  fi
+  RND_NAME=$(openssl rand -hex 16)
+  COV_PROFILE=${V2RAY_COV}/${RND_NAME}.out
+  go test -tags "json coverage" -coverprofile=${COV_PROFILE} -coverpkg=$DEP $DIR || FAIL=1
 }
 
+rm -rf ${V2RAY_OUT}
+mkdir -p ${V2RAY_COV}
 touch ${COVERAGE_FILE}
 
 TEST_FILES=(./*_test.go)
@@ -28,14 +31,17 @@ for DIR in $(find * -type d -not -path "*.git*"); do
   fi
 done
 
-cat ${COVERAGE_FILE} | sort -t: -k1 | grep -vw "testing" > coverallsorted.out
-echo "mode: set" | cat - coverallsorted.out > ${COVERAGE_FILE}
-rm coverallsorted.out
+for OUT_FILE in $(find ${V2RAY_COV} -name "*.out"); do
+  echo "Merging file ${OUT_FILE}"
+  cat ${OUT_FILE} | grep -v "mode: set" >> ${COVERAGE_FILE}
+done
+
+COV_SORTED=${V2RAY_COV}/coverallsorted.out
+cat ${COVERAGE_FILE} | sort -t: -k1 | grep -vw "testing" > ${COV_SORTED}
+echo "mode: set" | cat - ${COV_SORTED} > ${COVERAGE_FILE}
 
 if [ "$FAIL" -eq 0 ]; then
   bash <(curl -s https://codecov.io/bash) -f ${COVERAGE_FILE} || echo "Codecov did not collect coverage reports."
 fi
 
-rm -f ${COVERAGE_FILE}
-
 exit $FAIL
diff --git a/testing/scenarios/server_env.go b/testing/scenarios/server_env.go
index 541d387d3..d548aaba2 100644
--- a/testing/scenarios/server_env.go
+++ b/testing/scenarios/server_env.go
@@ -1,7 +1,6 @@
 package scenarios
 
 import (
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -24,26 +23,20 @@ import (
 
 var (
 	runningServers = make([]*exec.Cmd, 0, 10)
-
-	binaryPath string
 )
 
+func GetTestBinaryPath() string {
+	file := filepath.Join(os.Getenv("GOPATH"), "out", "v2ray", "v2ray.test")
+	if runtime.GOOS == "windows" {
+		file += ".exe"
+	}
+	return file
+}
+
 func GetSourcePath() string {
 	return filepath.Join("github.com", "v2ray", "v2ray-core", "shell", "point", "main")
 }
 
-func FillBinaryPath() error {
-	dir, err := ioutil.TempDir("", "v2ray")
-	if err != nil {
-		return err
-	}
-	binaryPath = filepath.Join(dir, "v2ray")
-	if runtime.GOOS == "windows" {
-		binaryPath += ".exe"
-	}
-	return nil
-}
-
 func TestFile(filename string) string {
 	return filepath.Join(os.Getenv("GOPATH"), "src", "github.com", "v2ray", "v2ray-core", "testing", "scenarios", "data", filename)
 }
@@ -89,7 +82,8 @@ func InitializeServer(configFile string) error {
 func CloseAllServers() {
 	log.Info("Closing all servers.")
 	for _, server := range runningServers {
-		server.Process.Kill()
+		server.Process.Signal(os.Interrupt)
+		server.Process.Wait()
 	}
 	runningServers = make([]*exec.Cmd, 0, 10)
 	log.Info("All server closed.")
diff --git a/testing/scenarios/server_env_coverage.go b/testing/scenarios/server_env_coverage.go
index e923ce5a5..ffce2113d 100644
--- a/testing/scenarios/server_env_coverage.go
+++ b/testing/scenarios/server_env_coverage.go
@@ -6,28 +6,26 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+
+	"github.com/v2ray/v2ray-core/common/uuid"
 )
 
 func BuildV2Ray() error {
+	binaryPath := GetTestBinaryPath()
 	if _, err := os.Stat(binaryPath); err == nil {
 		return nil
 	}
 
-	if err := FillBinaryPath(); err != nil {
-		return err
-	}
-
 	cmd := exec.Command("go", "test", "-tags", "json coverage coveragemain", "-coverpkg", "github.com/v2ray/v2ray-core/...", "-c", "-o", binaryPath, GetSourcePath())
 	return cmd.Run()
 }
 
 func RunV2Ray(configFile string) *exec.Cmd {
-	profile := "coversingle.out"
-	wd, err := os.Getwd()
-	if err == nil {
-		profile = filepath.Join(wd, profile)
-	}
-	proc := exec.Command(binaryPath, "-config", configFile, "-test.run", "TestRunMainForCoverage", "-test.coverprofile", profile)
+	binaryPath := GetTestBinaryPath()
+
+	covDir := filepath.Join(os.Getenv("GOPATH"), "out", "v2ray", "cov")
+	profile := uuid.New().String() + ".out"
+	proc := exec.Command(binaryPath, "-config", configFile, "-test.run", "TestRunMainForCoverage", "-test.coverprofile", profile, "-test.outputdir", covDir)
 	proc.Stderr = os.Stderr
 	proc.Stdout = os.Stdout
 
diff --git a/testing/scenarios/server_env_regular.go b/testing/scenarios/server_env_regular.go
index 3ecfc5286..307bb93ec 100644
--- a/testing/scenarios/server_env_regular.go
+++ b/testing/scenarios/server_env_regular.go
@@ -8,20 +8,18 @@ import (
 )
 
 func BuildV2Ray() error {
+	binaryPath := GetTestBinaryPath()
 	if _, err := os.Stat(binaryPath); err == nil {
 		return nil
 	}
 
-	if err := FillBinaryPath(); err != nil {
-		return err
-	}
-
 	cmd := exec.Command("go", "build", "-tags=json", "-o="+binaryPath, GetSourcePath())
 	return cmd.Run()
 }
 
 func RunV2Ray(configFile string) *exec.Cmd {
-	proc := exec.Command(binaryPath, "-config="+configFile)
+	binaryPath := GetTestBinaryPath()
+	proc := exec.Command(binaryPath, "-config", configFile)
 	proc.Stderr = os.Stderr
 	proc.Stdout = os.Stdout