input: Write a python function to scrape and parse the HTML content of a given URL and extract all the text within paragraph tags.
  ```python
  import requests
  from bs4 import BeautifulSoup
  
  def extract_paragraph_text(url):
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      paragraphs = soup.find_all('p')
      return [p.get_text() for p in paragraphs]
  
  # Test cases
  assert 'Expected text in paragraph' in extract_paragraph_text('http://example.com')
  assert len(extract_paragraph_text('http://example.com')) > 0
  assert all(isinstance(text, str) for text in extract_paragraph_text('http://example.com'))
output: import requests
  from bs4 import BeautifulSoup
  
  def extract_paragraph_text(url):
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      paragraphs = soup.find_all('p')
      return [p.get_text() for p in paragraphs]