fix race condition in isPatchable func and remove a test (#10)

patcher.go

@@ -113,6 +113,8 @@ func (p *Patch) Unpatch() error {
 }
 
 func isPatchable(target, redirection *reflect.Value) error {
+	patchLock.Lock()
+	defer patchLock.Unlock()
 	if target.Kind() != reflect.Func || redirection.Kind() != reflect.Func {
 		return errors.New("the target and/or redirection is not a Func")
 	}

patcher_test.go

@@ -2,9 +2,7 @@ package mpatch
 
 import (
 	"reflect"
-	"runtime"
 	"testing"
-	"time"
 )
 
 //go:noinline
@@ -136,44 +134,3 @@ func TestInstanceValuePatcher(t *testing.T) {
 		t.Fatal("The unpatch did not work")
 	}
 }
-
-var slice []int
-
-//go:noinline
-func TestGarbageCollectorExperiment(t *testing.T) {
-
-	for i := 0; i < 10000000; i++ {
-		slice = append(slice, i)
-	}
-	go func() {
-		var sl []int
-		for i := 0; i < 10000000; i++ {
-			sl = append(slice, i)
-		}
-		_ = sl
-	}()
-	<-time.After(time.Second)
-
-	aVal := methodA
-	ptr01 := reflect.ValueOf(aVal).Pointer()
-	slice = nil
-	runtime.GC()
-	for i := 0; i < 10000000; i++ {
-		slice = append(slice, i)
-	}
-	go func() {
-		var sl []int
-		for i := 0; i < 10000000; i++ {
-			sl = append(slice, i)
-		}
-		_ = sl
-	}()
-	<-time.After(time.Second)
-	slice = nil
-	runtime.GC()
-	ptr02 := reflect.ValueOf(aVal).Pointer()
-
-	if ptr01 != ptr02 {
-		t.Fail()
-	}
-}