[v4] fix out-of-bounds behavior in seeker buffer and add tests (#219)

* add check negative position to Read() and write tests

* add tests for Write() method

* add tests for Write() method

* add checks of whence and negative position to Seek() and write tests

* add tests for Rewind()

* add tests for Close()

* add tests for Reset()

* add tests for Len()

* add tests for Bytes()

* tests polishing

* tests polishing

* tests polishing

* tests polishing

store/noop_test.go

@@ -2,6 +2,7 @@ package store
 
 import (
 	"context"
+	"errors"
 	"testing"
 )
 
@@ -25,7 +26,8 @@ func TestHook(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := s.Exists(context.TODO(), "test"); err != nil {
+	err := s.Exists(context.TODO(), "test")
+	if !errors.Is(err, ErrNotFound) {
 		t.Fatal(err)
 	}