pytest-bdd/pytest_bdd/parser.py

466 lines
15 KiB
Python

import os.path
import re
import textwrap
import typing
from collections import OrderedDict
from . import exceptions, types
SPLIT_LINE_RE = re.compile(r"(?<!\\)\|")
STEP_PARAM_RE = re.compile(r"<(.+?)>")
COMMENT_RE = re.compile(r"(^|(?<=\s))#")
STEP_PREFIXES = [
("Feature: ", types.FEATURE),
("Scenario Outline: ", types.SCENARIO_OUTLINE),
("Examples: Vertical", types.EXAMPLES_VERTICAL),
("Examples:", types.EXAMPLES),
("Scenario: ", types.SCENARIO),
("Background:", types.BACKGROUND),
("Given ", types.GIVEN),
("When ", types.WHEN),
("Then ", types.THEN),
("@", types.TAG),
# Continuation of the previously mentioned step type
("And ", None),
("But ", None),
]
def split_line(line):
"""Split the given Examples line.
:param str|unicode line: Feature file Examples line.
:return: List of strings.
"""
return [cell.replace("\\|", "|").strip() for cell in SPLIT_LINE_RE.split(line)[1:-1]]
def parse_line(line):
"""Parse step line to get the step prefix (Scenario, Given, When, Then or And) and the actual step name.
:param line: Line of the Feature file.
:return: `tuple` in form ("<prefix>", "<Line without the prefix>").
"""
for prefix, _ in STEP_PREFIXES:
if line.startswith(prefix):
return prefix.strip(), line[len(prefix) :].strip()
return "", line
def strip_comments(line):
"""Remove comments.
:param str line: Line of the Feature file.
:return: Stripped line.
"""
res = COMMENT_RE.search(line)
if res:
line = line[: res.start()]
return line.strip()
def get_step_type(line):
"""Detect step type by the beginning of the line.
:param str line: Line of the Feature file.
:return: SCENARIO, GIVEN, WHEN, THEN, or `None` if can't be detected.
"""
for prefix, _type in STEP_PREFIXES:
if line.startswith(prefix):
return _type
def parse_feature(basedir: str, filename: str, encoding: str = "utf-8") -> "Feature":
"""Parse the feature file.
:param str basedir: Feature files base directory.
:param str filename: Relative path to the feature file.
:param str encoding: Feature file encoding (utf-8 by default).
"""
abs_filename = os.path.abspath(os.path.join(basedir, filename))
rel_filename = os.path.join(os.path.basename(basedir), filename)
feature = Feature(
scenarios=OrderedDict(),
filename=abs_filename,
rel_filename=rel_filename,
line_number=1,
name=None,
tags=set(),
examples=Examples(),
background=None,
description="",
)
scenario: typing.Optional[ScenarioTemplate] = None
mode = None
prev_mode = None
description: typing.List[str] = []
step = None
multiline_step = False
prev_line = None
with open(abs_filename, encoding=encoding) as f:
content = f.read()
for line_number, line in enumerate(content.splitlines(), start=1):
unindented_line = line.lstrip()
line_indent = len(line) - len(unindented_line)
if step and (step.indent < line_indent or ((not unindented_line) and multiline_step)):
multiline_step = True
# multiline step, so just add line and continue
step.add_line(line)
continue
else:
step = None
multiline_step = False
stripped_line = line.strip()
clean_line = strip_comments(line)
if not clean_line and (not prev_mode or prev_mode not in types.FEATURE):
continue
mode = get_step_type(clean_line) or mode
allowed_prev_mode = (types.BACKGROUND, types.GIVEN, types.WHEN)
if not scenario and prev_mode not in allowed_prev_mode and mode in types.STEP_TYPES:
raise exceptions.FeatureError(
"Step definition outside of a Scenario or a Background", line_number, clean_line, filename
)
if mode == types.FEATURE:
if prev_mode is None or prev_mode == types.TAG:
_, feature.name = parse_line(clean_line)
feature.line_number = line_number
feature.tags = get_tags(prev_line)
elif prev_mode == types.FEATURE:
description.append(clean_line)
else:
raise exceptions.FeatureError(
"Multiple features are not allowed in a single feature file",
line_number,
clean_line,
filename,
)
prev_mode = mode
# Remove Feature, Given, When, Then, And
keyword, parsed_line = parse_line(clean_line)
if mode in [types.SCENARIO, types.SCENARIO_OUTLINE]:
tags = get_tags(prev_line)
feature.scenarios[parsed_line] = scenario = ScenarioTemplate(
feature=feature, name=parsed_line, line_number=line_number, tags=tags
)
elif mode == types.BACKGROUND:
feature.background = Background(feature=feature, line_number=line_number)
elif mode == types.EXAMPLES:
mode = types.EXAMPLES_HEADERS
(scenario or feature).examples.line_number = line_number
elif mode == types.EXAMPLES_VERTICAL:
mode = types.EXAMPLE_LINE_VERTICAL
(scenario or feature).examples.line_number = line_number
elif mode == types.EXAMPLES_HEADERS:
(scenario or feature).examples.set_param_names([l for l in split_line(parsed_line) if l])
mode = types.EXAMPLE_LINE
elif mode == types.EXAMPLE_LINE:
(scenario or feature).examples.add_example([l for l in split_line(stripped_line)])
elif mode == types.EXAMPLE_LINE_VERTICAL:
param_line_parts = [l for l in split_line(stripped_line)]
try:
(scenario or feature).examples.add_example_row(param_line_parts[0], param_line_parts[1:])
except exceptions.ExamplesNotValidError as exc:
if scenario:
raise exceptions.FeatureError(
f"Scenario has not valid examples. {exc.args[0]}",
line_number,
clean_line,
filename,
)
else:
raise exceptions.FeatureError(
f"Feature has not valid examples. {exc.args[0]}",
line_number,
clean_line,
filename,
)
elif mode and mode not in (types.FEATURE, types.TAG):
step = Step(name=parsed_line, type=mode, indent=line_indent, line_number=line_number, keyword=keyword)
if feature.background and not scenario:
target = feature.background
else:
target = scenario
target.add_step(step)
prev_line = clean_line
feature.description = "\n".join(description).strip()
return feature
class Feature:
"""Feature."""
def __init__(self, scenarios, filename, rel_filename, name, tags, examples, background, line_number, description):
self.scenarios: typing.Dict[str, ScenarioTemplate] = scenarios
self.rel_filename = rel_filename
self.filename = filename
self.tags = tags
self.examples = examples
self.name = name
self.line_number = line_number
self.description = description
self.background = background
class ScenarioTemplate:
"""A scenario template.
Created when parsing the feature file, it will then be combined with the examples to create a Scenario."""
def __init__(self, feature: Feature, name: str, line_number: int, tags=None):
"""
:param str name: Scenario name.
:param int line_number: Scenario line number.
:param set tags: Set of tags.
"""
self.feature = feature
self.name = name
self._steps: typing.List[Step] = []
self.example_tables = [Examples()]
self.line_number = line_number
self.tags = tags or set()
@property
def examples(self):
"""Current examples."""
return self.example_tables[-1]
def add_step(self, step):
"""Add step to the scenario.
:param pytest_bdd.parser.Step step: Step.
"""
step.scenario = self
self._steps.append(step)
@property
def steps(self):
background = self.feature.background
return (background.steps if background else []) + self._steps
def render(self, context: typing.Mapping[str, typing.Any]) -> "Scenario":
"""Render a single scenario given a context (examples)."""
steps = [
Step(
name=templated_step.render(context),
type=templated_step.type,
indent=templated_step.indent,
line_number=templated_step.line_number,
keyword=templated_step.keyword,
)
for templated_step in self.steps
]
return Scenario(feature=self.feature, name=self.name, line_number=self.line_number, steps=steps, tags=self.tags)
def validate(self):
"""Validate the scenario.
:raises ScenarioValidationError: when scenario is not valid
"""
params = frozenset(sum((list(step.params) for step in self.steps), []))
example_params = set(self.examples.example_params + self.feature.examples.example_params)
if params and example_params and params != example_params:
raise exceptions.ScenarioExamplesNotValidError(
"""Scenario "{}" in the feature "{}" has not valid examples. """
"""Set of step parameters {} should match set of example values {}.""".format(
self.name, self.feature.filename, sorted(params), sorted(example_params)
)
)
class Scenario:
"""Scenario."""
def __init__(self, feature: Feature, name: str, line_number: int, steps: "typing.List[Step]", tags=None):
"""Scenario constructor.
:param pytest_bdd.parser.Feature feature: Feature.
:param str name: Scenario name.
:param int line_number: Scenario line number.
:param set tags: Set of tags.
"""
self.feature = feature
self.name = name
self.steps = steps
self.line_number = line_number
self.tags = tags or set()
self.failed = False
class Step:
"""Step."""
def __init__(self, name, type, indent, line_number, keyword):
"""Step constructor.
:param str name: step name.
:param str type: step type.
:param int indent: step text indent.
:param int line_number: line number.
:param str keyword: step keyword.
"""
self.name = name
self.keyword = keyword
self.lines = []
self.indent = indent
self.type = type
self.line_number = line_number
self.failed = False
self.start = 0
self.stop = 0
self.scenario = None
self.background = None
def add_line(self, line):
"""Add line to the multiple step.
:param str line: Line of text - the continuation of the step name.
"""
self.lines.append(line)
@property
def name(self):
"""Get step name."""
multilines_content = textwrap.dedent("\n".join(self.lines)) if self.lines else ""
# Remove the multiline quotes, if present.
multilines_content = re.sub(
pattern=r'^"""\n(?P<content>.*)\n"""$',
repl=r"\g<content>",
string=multilines_content,
flags=re.DOTALL, # Needed to make the "." match also new lines
)
lines = [self._name] + [multilines_content]
return "\n".join(lines).strip()
@name.setter
def name(self, value):
"""Set step name."""
self._name = value
def __str__(self):
"""Full step name including the type."""
return f'{self.type.capitalize()} "{self.name}"'
@property
def params(self):
"""Get step params."""
return tuple(frozenset(STEP_PARAM_RE.findall(self.name)))
def render(self, context: typing.Mapping[str, typing.Any]):
def replacer(m: typing.Match):
varname = m.group(1)
return str(context[varname])
return STEP_PARAM_RE.sub(replacer, self.name)
class Background:
"""Background."""
def __init__(self, feature, line_number):
"""Background constructor.
:param pytest_bdd.parser.Feature feature: Feature.
:param int line_number: Line number.
"""
self.feature = feature
self.line_number = line_number
self.steps = []
def add_step(self, step):
"""Add step to the background."""
step.background = self
self.steps.append(step)
class Examples:
"""Example table."""
def __init__(self):
"""Initialize examples instance."""
self.example_params = []
self.examples = []
self.vertical_examples = []
self.line_number = None
self.name = None
def set_param_names(self, keys):
"""Set parameter names.
:param names: `list` of `string` parameter names.
"""
self.example_params = [str(key) for key in keys]
def add_example(self, values):
"""Add example.
:param values: `list` of `string` parameter values.
"""
self.examples.append(values)
def add_example_row(self, param, values):
"""Add example row.
:param param: `str` parameter name
:param values: `list` of `string` parameter values
"""
if param in self.example_params:
raise exceptions.ExamplesNotValidError(
f"""Example rows should contain unique parameters. "{param}" appeared more than once"""
)
self.example_params.append(param)
self.vertical_examples.append(values)
def as_contexts(self) -> typing.Iterable[typing.Dict[str, typing.Any]]:
param_count = len(self.example_params)
if self.vertical_examples and not self.examples:
for value_index in range(len(self.vertical_examples[0])):
example = []
for param_index in range(param_count):
example.append(self.vertical_examples[param_index][value_index])
self.examples.append(example)
if not self.examples:
return
header, rows = self.example_params, self.examples
for row in rows:
assert len(header) == len(row)
yield dict(zip(header, row))
def __bool__(self):
"""Bool comparison."""
return bool(self.vertical_examples or self.examples)
def get_tags(line):
"""Get tags out of the given line.
:param str line: Feature file text line.
:return: List of tags.
"""
if not line or not line.strip().startswith("@"):
return set()
return {tag.lstrip("@") for tag in line.strip().split(" @") if len(tag) > 1}