Pytest: wait for Mermaid to render

tests/test_markdown.py

@@ -45,14 +45,14 @@ def page():
         '''))
 
     screen.open('/')
-    screen.wait(1.0)  # wait for Mermaid to render
     screen.should_contain('Mermaid')
+    screen.wait(1.0)  # wait for Mermaid to render
     assert screen.find_by_tag('svg').get_attribute('id') == f'{m.html_id}_mermaid_0'
-    assert screen.selenium.find_element(By.XPATH, '//span[p[contains(text(), "Node_A")]]').is_displayed()
+    _wait_for_xpath_displayed(screen, '//span[p[contains(text(), "Node_A")]]')
 
     screen.click('Set new content')
     screen.should_contain('New')
-    assert screen.selenium.find_element(By.XPATH, '//span[p[contains(text(), "Node_C")]]').is_displayed()
+    _wait_for_xpath_displayed(screen, '//span[p[contains(text(), "Node_C")]]')
     screen.should_not_contain('Node_A')
 
 
@@ -68,8 +68,8 @@ def page():
 
     screen.open('/')
     screen.click('Create Mermaid')
-    assert screen.selenium.find_element(By.XPATH, '//span[p[contains(text(), "Node_A")]]').is_displayed()
-    assert screen.selenium.find_element(By.XPATH, '//span[p[contains(text(), "Node_B")]]').is_displayed()
+    _wait_for_xpath_displayed(screen, '//span[p[contains(text(), "Node_A")]]')
+    _wait_for_xpath_displayed(screen, '//span[p[contains(text(), "Node_B")]]')
 
 
 def test_strip_indentation(screen: Screen):
@@ -102,3 +102,15 @@ def replace():
     screen.click('Replace')
     screen.should_contain('B')
     screen.should_not_contain('A')
+
+
+def _wait_for_xpath_displayed(screen: Screen, xpath: str, attempts: int = 5, delay: float = 0.2):
+    for _ in range(attempts):
+        try:
+            el = screen.selenium.find_element(By.XPATH, xpath)
+            if el.is_displayed():
+                return el
+        except Exception:
+            pass
+        screen.wait(delay)
+    raise AssertionError(f'{xpath} not displayed')

tests/test_mermaid.py

@@ -18,10 +18,12 @@ def page():
         '''))
 
     screen.open('/')
+    screen.should_contain('Node_A')
     node_a = screen.selenium.find_element(By.XPATH, '//span[p[contains(text(), "Node_A")]]')
     assert node_a.get_attribute('class') == 'nodeLabel'
 
     screen.click('Set new content')
+    screen.should_contain('Node_C')
     node_c = screen.selenium.find_element(By.XPATH, '//span[p[contains(text(), "Node_C")]]')
     assert node_c.get_attribute('class') == 'nodeLabel'
     screen.should_not_contain('Node_A')