given validation

pytest_bdd/feature.py

@@ -146,7 +146,7 @@ class Feature(object):
                 if mode == SCENARIO:
                     self.scenarios[line] = scenario = Scenario(line)
                 else:
-                    scenario.add_step(line)
+                    scenario.add_step(step_name=line, step_type=mode)
 
     @classmethod
     def get_feature(cls, filename):
@@ -176,7 +176,12 @@ class Scenario(object):
         self.params = set()
         self.steps = []
 
-    def add_step(self, step):
-        """Add step."""
-        self.params.update(get_step_params(step))
-        self.steps.append(step)
+    def add_step(self, step_name, step_type):
+        """Add step to the scenario.
+
+        :param step_name: Step name.
+        :param step_type: Step type.
+
+        """
+        self.params.update(get_step_params(step_name))
+        self.steps.append((step_name, step_type))

pytest_bdd/scenario.py

@@ -18,6 +18,7 @@ from _pytest import python
 
 from pytest_bdd.feature import Feature  # pragma: no cover
 from pytest_bdd.steps import recreate_function
+from pytest_bdd.types import GIVEN
 
 
 class ScenarioNotFound(Exception):  # pragma: no cover
@@ -28,6 +29,14 @@ class NotEnoughScenarioParams(Exception):  # pragma: no cover
     """Scenario function doesn't take enough parameters in the arguments."""
 
 
+class StepTypeError(Exception):  # pragma: no cover
+    """Step definition is not of the type expected in the scenario."""
+
+
+class GivenAlreadyUsed(Exception):  # pragma: no cover
+    """Fixture that implements the Given has been already used."""
+
+
 def _find_step_function(request, name):
     """Match the step defined by the regular expression pattern.
 
@@ -92,10 +101,29 @@ def scenario(feature_name, scenario_name):
                     )
                 )
 
+            givens = set()
             # Execute scenario steps
-            for step in scenario.steps:
-                step_func = _find_step_function(request, step)
+            for step_name, step_type in scenario.steps:
+                step_func = _find_step_function(request, step_name)
+
+                # Check the step types are called in the correct order
+                if step_func.step_type != step_type:
+                    raise StepTypeError('Wrong step type "{0}", expected {1}.'.format(step_func.step_type, step_type))
+
+                # Check if the fixture that implements given step has not been yet used by another given step
+                if step_type == GIVEN:
+                    if step_func.__name__ in givens:
+                        raise GivenAlreadyUsed(
+                            'Fixture "{0}" that implements this given step "{1}" has been already used.'.format(
+                                step_func.__name__, step_name,
+                            )
+                        )
+                    givens.add(step_func.__name__)
+
+                # Get the step argument values
                 kwargs = dict((arg, request.getfuncargvalue(arg)) for arg in inspect.getargspec(step_func).args)
+
+                # Execute the step
                 step_func(**kwargs)
 
         _scenario.pytestbdd_params = set()

pytest_bdd/steps.py

@@ -48,7 +48,7 @@ PY3 = sys.version_info[0] >= 3  # pragma: no cover
 class StepError(Exception):  # pragma: no cover
     """Step declaration error."""
 
-RE_TYPE = type(re.compile(''))
+RE_TYPE = type(re.compile(''))  # pragma: no cover
 
 
 def given(name, fixture=None):
@@ -64,8 +64,12 @@ def given(name, fixture=None):
 
     if fixture is not None:
         module = get_caller_module()
-        func = lambda: lambda request: request.getfuncargvalue(fixture)
-        contribute_to_module(module, remove_prefix(name), pytest.fixture(func))
+        step_func = lambda request: request.getfuncargvalue(fixture)
+        step_func.step_type = GIVEN
+        step_func.__name__ = fixture
+        func = pytest.fixture(lambda: step_func)
+        func.__doc__ = 'Alias for the "{0}" fixture.'.format(fixture)
+        contribute_to_module(module, remove_prefix(name), func)
         return _not_a_fixture_decorator
 
     return _step_decorator(GIVEN, name)
@@ -134,12 +138,13 @@ def _step_decorator(step_type, step_name):
             step_func.__doc__ = func.__doc__
 
         step_func.__name__ = step_name
+        step_func.step_type = step_type
 
         @pytest.fixture
         def lazy_step_func():
             return step_func
 
-        # Preserve a docstring
+        # Preserve the docstring
         lazy_step_func.__doc__ = func.__doc__
 
         if pattern:

tests/args/args_steps.feature

@@ -1,6 +1,5 @@
 Scenario: Every step takes a parameter with the same name
 	Given I have 1 Euro
-	#And I have 2 Euro
 	When I pay 2 Euro
 	And I pay 1 Euro
 	Then I should have 0 Euro

tests/args/subfolder/args.feature

@@ -1,4 +1,4 @@
-Scenario: Executed with steps matching regex step definitons
+Scenario: Executed with steps matching step definitons with arguments
     Given I have a foo fixture with value "foo"
     And there is a list
     When I append 1 to the list

tests/args/subfolder/test_args.py

@@ -1,7 +1,10 @@
 from pytest_bdd import scenario, given, then
 
 
-test_steps = scenario('regex.feature', 'Executed with steps matching regex step definitons')
+test_steps = scenario(
+    'args.feature',
+    'Executed with steps matching step definitons with arguments',
+)
 
 
 @given('I have a foo fixture with value "foo"')

tests/args/test_args_steps.py

@@ -4,14 +4,13 @@ from pytest_bdd import scenario, given, when, then
 
 
 test_steps = scenario(
-    'regex_steps.feature',
+    'args_steps.feature',
     'Every step takes a parameter with the same name'
 )
 
 
 @pytest.fixture
 def values():
-    #return ['1', '2', '2', '1', '0', '999999']
     return ['1', '2', '1', '0', '999999']
 
 

tox.ini

@@ -5,18 +5,17 @@ indexserver=
     pypi = https://pypi.python.org/simple
 
 [testenv]
-commands= py.test --pep8 --junitxml={envlogdir}/junit-{envname}.xml
+commands= py.test tests --pep8 --junitxml={envlogdir}/junit-{envname}.xml
 deps = -r{toxinidir}/requirements-testing.txt
 
 [testenv:py27-coverage]
-commands= py.test --cov=pytest_bdd --pep8 --junitxml={envlogdir}/junit-{envname}.xml
+commands= py.test tests --cov=pytest_bdd --pep8 --junitxml={envlogdir}/junit-{envname}.xml
 
 [testenv:py27-xdist]
 basepython=python2.7
 commands=
-  py.test -n3 -rfsxX \
+  py.test tests -n3 -rfsxX \
         --junitxml={envlogdir}/junit-{envname}.xml
 
 [pytest]
-addopts=tests
 pep8maxlinelength=120