refactor: internal package

internal/sandbox/semaphore_test.go

@@ -0,0 +1,45 @@
+package sandbox
+
+import "testing"
+
+func TestSemaphore(t *testing.T) {
+	t.Run("size", func(t *testing.T) {
+		sem := NewSemaphore(3)
+		if sem.Size() != 3 {
+			t.Errorf("Size: expected 3, got %d", sem.Size())
+		}
+	})
+	t.Run("acquire", func(t *testing.T) {
+		sem := NewSemaphore(2)
+		err := sem.Acquire()
+		if err != nil {
+			t.Fatalf("acquire #1: expected nil err")
+		}
+		err = sem.Acquire()
+		if err != nil {
+			t.Fatalf("acquire #2: expected nil err")
+		}
+		err = sem.Acquire()
+		if err != ErrBusy {
+			t.Fatalf("acquire #3: expected ErrBusy")
+		}
+	})
+	t.Run("release", func(t *testing.T) {
+		sem := NewSemaphore(2)
+		_ = sem.Acquire()
+		_ = sem.Acquire()
+		_ = sem.Acquire()
+
+		sem.Release()
+		err := sem.Acquire()
+		if err != nil {
+			t.Fatalf("acquire after release: expected nil err")
+		}
+	})
+	t.Run("release free", func(t *testing.T) {
+		sem := NewSemaphore(2)
+		sem.Release()
+		sem.Release()
+		sem.Release()
+	})
+}