Added kernel_protocol_version to kernelspec (#1483)

Although not required for kernel protocol < 5.5, this will simplify the
upgrade.
This needs jupyter/jupyter_client#1097 to be
merged first.

Author: JohanMabille

ipykernel/kernelspec.py

@@ -67,6 +67,7 @@ def get_kernel_dict(
         "display_name": "Python %i (ipykernel)" % sys.version_info[0],
         "language": "python",
         "metadata": {"debugger": True},
+        "kernel_protocol_version": "5.4",
     }
 
 

tests/test_kernelspec.py

@@ -35,6 +35,7 @@ def assert_kernel_dict(d):
     assert d["argv"] == make_ipkernel_cmd()
     assert d["display_name"] == "Python %i (ipykernel)" % sys.version_info[0]
     assert d["language"] == "python"
+    assert d["kernel_protocol_version"] == "5.4"
 
 
 def test_get_kernel_dict():
@@ -46,6 +47,7 @@ def assert_kernel_dict_with_profile(d):
     assert d["argv"] == make_ipkernel_cmd(extra_arguments=["--profile", "test"])
     assert d["display_name"] == "Python %i (ipykernel)" % sys.version_info[0]
     assert d["language"] == "python"
+    assert d["kernel_protocol_version"] == "5.4"
 
 
 def test_get_kernel_dict_with_profile():