def METHOD_NAME(self):
    ''' Test invalid enum definition. '''
    for file in PROTO_FILES:
        with open(file, "rt") as fin, self.subTest(file=file):
            isEnum = False
            enumName = ""
            saveStatement = ""
            for i, line in enumerate(fin, start=1):
                # Divide statement and comment. Concatenate multi line statements.
                # Search for comment ("//").
                matchComment = re.search("//", line)
                if matchComment is not None:
                    statement = line[:matchComment.start()]
                    comment = line[matchComment.end():]
                else:
                    statement = line
                    comment = ""
                # Add part of the statement from last line.
                statement = saveStatement + " " + statement
                saveStatement = ""
                # New line is not necessary. Remove for a better output.
                statement = statement.replace("\n", "")
                comment = comment.replace("\n", "")
                # Is statement complete
                matchSep = re.search(r"[{};]", statement)
                if matchSep is None:
                    saveStatement = statement
                    statement = ""
                else:
                    saveStatement = statement[matchSep.end():]
                    statement = statement[:matchSep.end()]
                # This section will check PascalCase for enums and check enum name?
                if isEnum is True:
                    matchName = re.search(r"\b\w[\S:]+\b", statement)
                    if matchName is not None:
                        checkName = statement[matchName.start():matchName.end()]
                # Search for "enum".
                matchEnum = re.search(r"\benum\b", statement)
                if matchEnum is not None:
                    isEnum = True
                    endOfLine = statement[matchEnum.end():]
                    matchName = re.search(r"\b\w[\S]*\b", endOfLine)
                    if matchName is not None:
                        # Test to ensure no special characters are in ENUM name.
                        matchNameConv = re.search(r"\b[A-Z][a-zA-Z0-9]*\b", endOfLine[matchName.start():matchName.end()])
                        self.assertIsNotNone(matchNameConv, file + " in line " + str(i) + ": enum name wrong. '" + endOfLine[matchName.start():matchName.end()] + "'")
                        enumName = self.convert(endOfLine[matchName.start():matchName.end()]) + "_"
                # Search for a closing brace.
                matchClosingBrace = re.search("}", statement)
                if isEnum is True and matchClosingBrace is not None:
                    isEnum = False
                    enumName = ""