Add test

Author: davidbrochart

.gitignore

@@ -147,3 +147,6 @@ jupyter_ydoc/_version.py
 !.yarn/versions
 docs/source/api
 docs/source/changelog.md
+# pixi environments
+.pixi
+

tests/test_ydocs.py

@@ -0,0 +1,21 @@
+from jupyter_ydoc import YBlob
+
+
+def test_yblob():
+    yblob = YBlob()
+    assert yblob.get() == b""
+    yblob.set(b"012")
+    assert yblob.get() == b"012"
+    changes = []
+
+    def callback(topic, event):
+        print(topic, event)
+        changes.append((topic, event))
+
+    yblob.observe(callback)
+    yblob.set(b"345")
+    assert len(changes) == 1
+    topic, event = changes[0]
+    assert topic == "source"
+    assert event.keys["bytes"]["oldValue"] == b"012"
+    assert event.keys["bytes"]["newValue"] == b"345"