add test code for face recognition api

+import base64
+import face_recognition
+import numpy as np
+from cv2 import cv2
+import os
+
+known_path = './images/' # directory path of known faces
+image_format = 'jpg'
+
+# image to base64 encoding
+# you have to set 'encoded_image' to frame code
+with open("./images/obama.jpg", "rb") as img_file:
+    encoded_image = base64.b64encode(img_file.read())
+
+#base64 to image(uint8) decoding
+img64_decode = base64.decodebytes(encoded_image)
+im_arr = np.frombuffer(img64_decode, dtype=np.uint8)
+decoded_img = cv2.imdecode(im_arr, flags=cv2.IMREAD_COLOR)
+
+#encoding frame
+unknown_face_encoding = face_recognition.face_encodings(decoded_img)[0]
+
+# Load & encode all images from known_path
+known_list = os.listdir(known_path)
+known_faces = []
+
+
+for f in known_list : 
+    if f.split('.')[-1] != image_format : continue
+    known_img = face_recognition.load_image_file(known_path+f)
+    known_img_encoding = face_recognition.face_encodings(known_img)[0]
+    known_faces.append(known_img_encoding)
+
+# results is an array of True/False telling if the unknown face matched anyone in the known_faces array
+results = face_recognition.compare_faces(known_faces, unknown_face_encoding)
+print(results)
+#print(not True in results)
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