--- /dev/null
+''''''
+
+'\''
+'"'
+"'"
+"\""
+"Hello"
+"Don't do that"
+'Here is a "'
+'What\'s the deal here?'
+"What's the deal \"here\"?"
+"And \"here\"?"
+"""Strings with "" in them"""
+'''Strings with "" in them'''
+'''Here's a "'''
+'''Here's a " '''
+'''Just a normal triple
+quote'''
+f"just a normal {f} string"
+f'''This is a triple-quoted {f}-string'''
+f'MOAR {" ".join([])}'
+f"MOAR {' '.join([])}"
+r"raw string ftw"
+r'Date d\'expiration:(.*)'
+r'Tricky "quote'
+r'Not-so-tricky \"quote'
+rf'{yay}'
+'\n\
+The \"quick\"\n\
+brown fox\n\
+jumps over\n\
+the \'lazy\' dog.\n\
+'
+re.compile(r'[\\"]')
+"x = ''; y = \"\""
+"x = '''; y = \"\""
+"x = ''''; y = \"\""
+"x = '' ''; y = \"\""
+"x = ''; y = \"\"\""
+"x = '''; y = \"\"\"\""
+"x = ''''; y = \"\"\"\"\""
+"x = '' ''; y = \"\"\"\"\""
+'unnecessary \"\"escaping'
+"unnecessary \'\'escaping"
+'\\""'
+"\\''"
+'Lots of \\\\\\\\\'quotes\''
+f'{y * " "} \'{z}\''
+f'{{y * " "}} \'{z}\''
+f'\'{z}\' {y * " "}'
+f'{y * x} \'{z}\''
+'\'{z}\' {y * " "}'
+'{y * x} \'{z}\''
+
+# We must bail out if changing the quotes would introduce backslashes in f-string
+# expressions. xref: https://github.com/psf/black/issues/2348
+f"\"{b}\"{' ' * (long-len(b)+1)}: \"{sts}\",\n"
+f"\"{a}\"{'hello' * b}\"{c}\""
+
+# output
+
+""""""
+
+"'"
+'"'
+"'"
+'"'
+"Hello"
+"Don't do that"
+'Here is a "'
+"What's the deal here?"
+'What\'s the deal "here"?'
+'And "here"?'
+"""Strings with "" in them"""
+"""Strings with "" in them"""
+'''Here's a "'''
+"""Here's a " """
+"""Just a normal triple
+quote"""
+f"just a normal {f} string"
+f"""This is a triple-quoted {f}-string"""
+f'MOAR {" ".join([])}'
+f"MOAR {' '.join([])}"
+r"raw string ftw"
+r"Date d\'expiration:(.*)"
+r'Tricky "quote'
+r"Not-so-tricky \"quote"
+rf"{yay}"
+"\nThe \"quick\"\nbrown fox\njumps over\nthe 'lazy' dog.\n"
+re.compile(r'[\\"]')
+"x = ''; y = \"\""
+"x = '''; y = \"\""
+"x = ''''; y = \"\""
+"x = '' ''; y = \"\""
+'x = \'\'; y = """'
+'x = \'\'\'; y = """"'
+'x = \'\'\'\'; y = """""'
+'x = \'\' \'\'; y = """""'
+'unnecessary ""escaping'
+"unnecessary ''escaping"
+'\\""'
+"\\''"
+"Lots of \\\\\\\\'quotes'"
+f'{y * " "} \'{z}\''
+f"{{y * \" \"}} '{z}'"
+f'\'{z}\' {y * " "}'
+f"{y * x} '{z}'"
+"'{z}' {y * \" \"}"
+"{y * x} '{z}'"
+
+# We must bail out if changing the quotes would introduce backslashes in f-string
+# expressions. xref: https://github.com/psf/black/issues/2348
+f"\"{b}\"{' ' * (long-len(b)+1)}: \"{sts}\",\n"
+f"\"{a}\"{'hello' * b}\"{c}\""