Fix CI problem of preheated kernels tests

.github/workflows/ui-tests.yml

@@ -21,7 +21,7 @@ jobs:
       - name: Set up Node
         uses: actions/setup-node@v1
         with:
-          node-version: '14.x'
+          node-version: '16.x'
 
       - name: Cache pip on Linux
         uses: actions/cache@v2

tests/app/preheat_activation_test.py

@@ -36,6 +36,7 @@ async def test_request_before_kernel_heated(http_server_client, base_url):
     time, text = await send_request(sc=http_server_client, url=base_url)
     assert 'hello world' in text
     assert time > NOTEBOOK_EXECUTION_TIME
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)
 
 
 async def test_render_time_with_preheated_kernel(http_server_client, base_url):
@@ -48,6 +49,7 @@ async def test_render_time_with_preheated_kernel(http_server_client, base_url):
                                     wait=NOTEBOOK_EXECUTION_TIME + 2)
     assert 'hello world' in text
     assert time < TIME_THRESHOLD
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)
 
 
 async def test_render_time_with_multiple_requests(http_server_client,
@@ -65,6 +67,7 @@ async def test_render_time_with_multiple_requests(http_server_client,
         time_list.append(time)
 
     assert time_list[1] > time_list[0]  # Render time for a normal kernel is bigger than a a preheated kernel
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)
 
 
 async def test_request_with_query(http_server_client, base_url):
@@ -77,6 +80,7 @@ async def test_request_with_query(http_server_client, base_url):
                                  url=url,
                                  wait=NOTEBOOK_EXECUTION_TIME + 1)
     assert time < TIME_THRESHOLD
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)
 
 
 async def test_request_with_theme_parameter(http_server_client, base_url):

tests/app/preheat_configuration_test.py

@@ -4,7 +4,7 @@
 import os
 
 BASE_DIR = os.path.dirname(__file__)
-NOTEBOOK_EXECUTION_TIME = 2
+NOTEBOOK_EXECUTION_TIME = 3
 NUMBER_PREHEATED_KERNEL = 2
 TIME_THRESHOLD = 1
 
@@ -48,9 +48,11 @@ async def test_refill_kernel_asynchronously(http_server_client, base_url):
     assert len(fast) > 1
     assert len(slow) > 1
     assert len(fast) + len(slow) == 5*NUMBER_PREHEATED_KERNEL
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)
 
 
 async def test_env_variable_defined_in_kernel(http_server_client, base_url):
     await asyncio.sleep(NUMBER_PREHEATED_KERNEL*NOTEBOOK_EXECUTION_TIME + 1)
     _, text = await send_request(sc=http_server_client, url=base_url)
     assert "bar" in text
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)

tests/app/preheat_multiple_notebooks_test.py

@@ -40,6 +40,7 @@ async def test_render_notebook_with_heated_kernel(http_server_client, base_url):
 
     assert 'hello world' in text
     assert time < TIME_THRESHOLD
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)
 
 
 async def test_render_blacklisted_notebook_with_nornal_kernel(http_server_client, base_url):
@@ -48,3 +49,4 @@ async def test_render_blacklisted_notebook_with_nornal_kernel(http_server_client
 
     assert 'hello world' in text
     assert time > TIME_THRESHOLD
+    await asyncio.sleep(NOTEBOOK_EXECUTION_TIME + 1)

voila/voila_kernel_manager.py

@@ -146,7 +146,7 @@ async def get_rendered_notebook(
                 render_task: asyncio.Task = content['task']
                 kernel_id: str = content['kernel_id']
                 renderer.stop_generator = True
-                self.log.info('Using pre-heated kernel: %s for %s', 'kernel_id', notebook_name)
+                self.log.info('Using pre-heated kernel: %s for %s', kernel_id, notebook_name)
                 self.fill_if_needed(delay=None, notebook_name=notebook_name, **kwargs)
 
                 return render_task, renderer.rendered_cache, kernel_id