diff --git a/all_test.go b/all_test.go
index fbd12e5..6256b0b 100644
--- a/all_test.go
+++ b/all_test.go
@@ -475,3 +475,17 @@ func (r *SleepyReader) Read(p []byte) (int, error) {
 	}
 	return n, e
 }
+
+func TestOptions_NumberOfWorkers(t *testing.T) {
+	opt := Options{NumberOfWorkers: 3}
+	err := Copy("test/data/case19", "test/data.copy/case19", opt)
+	Expect(t, err).ToBe(nil)
+}
+
+func TestOptions_PreferConcurrent(t *testing.T) {
+	opt := Options{NumberOfWorkers: 4, PreferConcurrent: func(sd, dd string) (bool, error) {
+		return strings.HasSuffix(sd, "concurrent"), nil
+	}}
+	err := Copy("test/data/case19", "test/data.copy/case19_preferconcurrent", opt)
+	Expect(t, err).ToBe(nil)
+}
diff --git a/test/data/case19/README.md b/test/data/case19/README.md
new file mode 100644
index 0000000..0c54877
--- /dev/null
+++ b/test/data/case19/README.md
@@ -0,0 +1 @@
+# Concurrent case
\ No newline at end of file
diff --git a/test/data/case19/bar_sequential/aaa.txt b/test/data/case19/bar_sequential/aaa.txt
new file mode 100644
index 0000000..e69de29
diff --git a/test/data/case19/bar_sequential/bbb.txt b/test/data/case19/bar_sequential/bbb.txt
new file mode 100644
index 0000000..e69de29
diff --git a/test/data/case19/foo_concurrent/ccc.txt b/test/data/case19/foo_concurrent/ccc.txt
new file mode 100644
index 0000000..e69de29
diff --git a/test/data/case19/foo_concurrent/ddd.txt b/test/data/case19/foo_concurrent/ddd.txt
new file mode 100644
index 0000000..e69de29