Python行为可选参数

Question

我正试图用Cucumber（Behave）编写一个测试。“给定”语句需要能够接受可选参数，它用于验证字符串中的内容

两种方案的功能语法示例如下：

Given Verify text "this is a test string"
When String validation is "success"
Then Store form contents.

Given Verify text "this is a test string" exclude "test,trial,hello"
When String validation is "success"
Then Store form contents.

我尝试实施的步骤是：

# Verify text "this is a test string" exclude "test,trial,hello"

@given('Verify text "{text_to_clean}" {?: exclude "{excluded}')
def step_verify_text(context, text_to_clean, excluded):
    context.verified = verify_string(text_to_clean, excluded)

我该怎么做？我试着使用可选的?符号，但我想不出来。使用可选参数需要做什么

我在macOS Catalina上使用Mac

Answer 1

可选部分的正则表达式：(?: exclude "(?P<excluded>[^"]*?)")?

如果没有对所有步骤使用Regex解析器，请将步骤匹配器恢复为默认的'parse'

use_step_matcher('re')


@given('Verify text "(?P<text_to_clean>[^"]*?)"(?: exclude "(?P<excluded>[^"]*?)")?')
def step_verify_text(context, text_to_clean, excluded):
    context.verified = verify_string(text_to_clean, excluded)


use_step_matcher('parse')

Answer 2

注意：feature文件名和steps文件夹中的文件名应该匹配

例如：如果feature文件名是question_regex.feature，那么steps文件夹中的文件名应该是question_regex.py

一,。选项-Regex解析器

功能/问题\正则表达式功能

Feature: regex question

  Scenario: first question regex
    Given Verify text "this is a string"
    Then parameter "excluded" is ""

  Scenario: second question regex
    Given Verify text "this is a test string" exclude "test,trial,hello"
    Then parameter "excluded" is "test,trial,hello"

功能/步骤/问题\u regex.py

from behave import use_step_matcher, given, when, then
use_step_matcher("re")

@given('Verify text "(?P<text_to_clean>.*?)"((?: exclude )"(?P<excluded>.*?)")?')
def step_verify_text(context, text_to_clean, excluded):
    context.myvar = excluded

@then('parameter "(?P<name>.*?)" is "(?P<result>.*?)"')
def step_verify_text(context, name, result):
    return getattr(context, name, None) == result

---

二,。选项-CFParse

功能/步骤/问题\u cfparse.feature

Feature: cfparse question

  Scenario: first question cfparse
    Given Verify text 2 "this is a test string"
    Then normal parameter "excluded" is ""

  Scenario: second question cfparse
    Given Verify text 2 "this is a test string" exclude "test,trial,hello"
    Then normal parameter "excluded" is "test,trial,hello"

  Scenario: second question cfparse
    Given Verify text 3 "this is a test string" exclude "hi,hello,I"
    Then normal parameter "excluded" is "hi,hello,I"

功能/步骤/问题\u cfparse.py

from behave import given, when, then, use_step_matcher, register_type
import parse
use_step_matcher("cfparse")

@parse.with_pattern(r'(?: exclude )"(.*?)"')
def parse_word_optional(text):
    print(text)
    return text.strip()

@parse.with_pattern(r'(?: exclude )')
def parse_exclude(text):
    return text.strip()

@parse.with_pattern(r'"(.*?)"')
def parse_word_between_quote(text):
    return text.strip()

register_type(my1_=parse_exclude)
register_type(quote_word=parse_word_between_quote)
register_type(my_=parse_word_optional)

@given('Verify text 2 "{text_to_clean}"{ignore1:my1_?}{excluded:quote_word?}')
def step_verify_text(context, text_to_clean, ignore1, excluded):
    context.excluded = excluded

@given('Verify text 3 "{text_to_clean}"{excluded:my_?}')
def step_verify_text(context, text_to_clean, excluded):
    context.excluded = excluded

@then('normal parameter "{name}" is {result:quote_word*}')
def step_verify_text(context, name, result):
    return getattr(context, name, None) == result

注意：cfparse如果有多个可选的parameters相继出现，那么解析器不是一个好的选择