diff --git a/boomer.go b/boomer.go
index dce0163..5053110 100644
--- a/boomer.go
+++ b/boomer.go
@@ -37,8 +37,7 @@ func (b *Boomer) Run(testcases ...*TestCase) {
 }
 
 func (b *Boomer) convertBoomerTask(testcase *TestCase) *boomer.Task {
-	runner := NewRunner()
-	runner = runner.SetDebug(b.debug)
+	runner := NewRunner().SetDebug(b.debug)
 	return &boomer.Task{
 		Name:   testcase.Config.Name,
 		Weight: testcase.Config.Weight,
diff --git a/runner.go b/runner.go
index d8779c2..9ac2ff5 100644
--- a/runner.go
+++ b/runner.go
@@ -8,10 +8,8 @@ import (
 	"github.com/imroc/req"
 )
 
-var defaultRunner = NewRunner()
-
 func Test(t *testing.T, testcases ...*TestCase) error {
-	return defaultRunner.WithTestingT(t).Run(testcases...)
+	return NewRunner().WithTestingT(t).SetDebug(true).Run(testcases...)
 }
 
 func NewRunner() *Runner {
diff --git a/step_test.go b/step_test.go
index 09d42d3..f6d00e9 100644
--- a/step_test.go
+++ b/step_test.go
@@ -77,10 +77,11 @@ func TestRunRequestRun(t *testing.T) {
 	config := &TConfig{
 		BaseURL: "https://postman-echo.com",
 	}
-	if err := defaultRunner.WithTestingT(t).SetDebug(true).runStep(stepGET, config); err != nil {
+	runner := NewRunner().SetDebug(true).WithTestingT(t)
+	if err := runner.runStep(stepGET, config); err != nil {
 		t.Fatalf("tStep.Run() error: %s", err)
 	}
-	if err := defaultRunner.WithTestingT(t).SetDebug(true).runStep(stepPOSTData, config); err != nil {
+	if err := runner.runStep(stepPOSTData, config); err != nil {
 		t.Fatalf("tStepPOSTData.Run() error: %s", err)
 	}
 }