implement a strip_pre configuration option (#218) (#222)

Signed-off-by: chrispy <chrispy@synopsys.com>

tests/test_args.py

@@ -2,7 +2,7 @@
 Test whitelisting/blacklisting of specific tags.
 
 """
-from markdownify import markdownify, LSTRIP, RSTRIP, STRIP
+from markdownify import markdownify, LSTRIP, RSTRIP, STRIP, STRIP_ONE
 from .utils import md
 
 
@@ -34,6 +34,13 @@ def test_strip_document():
     assert markdownify("<p>Hello</p>", strip_document=None) == "\n\nHello\n\n"
 
 
+def test_strip_pre():
+    assert markdownify("<pre>  \n  \n  Hello  \n  \n  </pre>") == "```\n  Hello\n```"
+    assert markdownify("<pre>  \n  \n  Hello  \n  \n  </pre>", strip_pre=STRIP) == "```\n  Hello\n```"
+    assert markdownify("<pre>  \n  \n  Hello  \n  \n  </pre>", strip_pre=STRIP_ONE) == "```\n  \n  Hello  \n  \n```"
+    assert markdownify("<pre>  \n  \n  Hello  \n  \n  </pre>", strip_pre=None) == "```\n  \n  \n  Hello  \n  \n  \n```"
+
+
 def bs4_options():
     assert markdownify("<p>Hello</p>", bs4_options="html.parser") == "Hello"
     assert markdownify("<p>Hello</p>", bs4_options=["html.parser"]) == "Hello"

tests/test_conversions.py

@@ -370,4 +370,4 @@ def test_spaces():
     assert md('test <blockquote> text </blockquote> after') == 'test\n> text\n\nafter'
     assert md(' <ol> <li> x </li> <li> y </li> </ol> ') == '\n\n1. x\n2. y\n'
     assert md(' <ul> <li> x </li> <li> y </li> </ol> ') == '\n\n* x\n* y\n'
-    assert md('test <pre> foo </pre> bar') == 'test\n\n```\n foo \n```\n\nbar'
+    assert md('test <pre> foo </pre> bar') == 'test\n\n```\n foo\n```\n\nbar'