Add opus codec test

tests/opus/main.cpp

@@ -0,0 +1,31 @@
+#include <fstream>
+#include <iostream>
+#include <vector>
+
+#include "OpusEncoderImpl.h"
+#include "opus/opus.h"
+
+int main() {
+  OpusEncoderImpl* opusEncoder = new OpusEncoderImpl(48000, 2);
+
+  std::ifstream inputFile("ls.pcm", std::ios::binary);
+  if (!inputFile) {
+    std::cerr << "Failed to open input file." << std::endl;
+    return -1;
+  }
+
+  char sample[960];
+  while (inputFile.read(sample, 960)) {
+    opusEncoder->Feed((unsigned char*)sample, 960);
+  }
+
+  // // 读取编码后的opus，一般放在单独线程，这里只是为了方便
+  // StreamInfo info;
+  // while (opusEncoder.PopFrame(info)) {
+  //   .....
+  // }
+
+  opusEncoder->Stop();
+
+  return 0;
+}