add more tests for prof (#322)

core/prof/profilecenter_test.go

@@ -0,0 +1,16 @@
+package prof
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReport(t *testing.T) {
+	once.Do(func() {})
+	assert.NotContains(t, generateReport(), "foo")
+	report("foo", time.Second)
+	assert.Contains(t, generateReport(), "foo")
+	report("foo", time.Second)
+}