test: add test with yml file

tests/unit/flow/test_flow_visualization.py

@@ -1,9 +1,8 @@
 import os
 import numpy as np
-
 from PIL import Image
-
 from jina.flow import Flow
+import glob
 
 
 def test_visualization():
@@ -18,3 +17,21 @@ def test_visualization():
         with Image.open(os.path.join(cur_dir, 'flow.jpg')) as flow_created:
             assert flow_original.size == flow_created.size
             np.testing.assert_array_almost_equal(flow_original, flow_created)
+
+    for i in glob.glob("*.jpg"):
+        os.remove(i)
+
+
+def test_visualization_with_yml_file():
+    cur_dir = os.path.dirname(os.path.abspath(__file__))
+
+    f = Flow.load_config(os.path.join(cur_dir, '../yaml/test_flow_visualization.yml'))
+
+    f.mermaidstr_to_jpg()
+    with Image.open(os.path.join(cur_dir, 'flow_original_yml.jpg')) as flow_original:
+        with Image.open(os.path.join(cur_dir, 'flow.jpg')) as flow_created:
+            assert flow_original.size == flow_created.size
+            np.testing.assert_array_almost_equal(flow_original, flow_created)
+
+    for i in glob.glob("*.jpg"):
+        os.remove(i)

tests/unit/yaml/test_flow_visualization.yml

@@ -0,0 +1,22 @@
+!Flow
+pods:
+  loader:
+    read_only: true
+  normalizer:
+    read_only: true
+  image_encoder:
+    read_only: true
+  image_vector_indexer:
+    read_only: true
+  image_kv_indexer:
+    needs: [gateway]
+  text_encoder:
+    timeout_ready: 600000
+    read_only: true
+    needs: [gateway]
+  text_indexer:
+    read_only: true
+  join_all:
+    uses: _merge
+    needs: [image_vector_indexer, image_kv_indexer, text_indexer]
+    read_only: true