Add default filters

docs/index.md

@@ -295,6 +295,17 @@ def test_good_datasets2(data):
     assert sqrt(data) > 0
 ```
 
+ - pytest-cases offers you an array of default filter for you to choose from in the `filters` module such as: `has_tag`, `has_prefix`, and etc. You can use logical operations on them like "and" (&) "or" (|) and "invert" (~) in order to create you own custom filters.
+
+```python
+from pytest_cases import filters
+
+@parametrize_with_cases("data", cases='.', 
+                        filter=filters.has_tag("success") & filters.has_prefix("case_b")
+def test_good_datasets3(data):
+    assert sqrt(data) > 0
+```
+
 
 ### b- Case functions
 

pytest_cases/filters.py

@@ -0,0 +1,57 @@
+import re
+
+from .case_info import CaseInfo
+
+
+class CaseFilter(object):
+    """
+    This class represents a case filter. You can use it in order to filter cases
+    to be used by `parametrize_by_cases`.
+
+    You can join filters with the "and" relation by using & operator and join them
+    by "or" relation using | operator.
+    Moreover, you can negate a filter by using ~.
+    """
+
+    def __init__(self, filter_function):
+        self.filter_function = filter_function
+
+    def __call__(self, case):
+        return self.filter_function(case)
+
+    def __and__(self, other):
+        return CaseFilter(
+            lambda case: self(case) and other(case)
+        )
+
+    def __rand__(self, other):
+        return self & other
+
+    def __or__(self, other):
+        return CaseFilter(
+            lambda case: self(case) or other(case)
+        )
+
+    def __ror__(self, other):
+        return self | other
+
+    def __invert__(self):
+        return CaseFilter(
+            lambda case: not self(case)
+        )
+
+
+def has_tag(tag_name):
+    return CaseFilter(lambda case: tag_name in CaseInfo.get_from(case).tags)
+
+
+def has_prefix(prefix):
+    return CaseFilter(lambda case: case.__name__.startswith(prefix))
+
+
+def has_suffix(suffix):
+    return CaseFilter(lambda case: case.__name__.endswith(suffix))
+
+
+def match_regex(regex):
+    return CaseFilter(lambda case: re.match(regex, case.__name__))

pytest_cases/tests/pytest_extension/parametrize_plus/test_filter.py

@@ -0,0 +1,67 @@
+from pytest_cases import filters, case, parametrize_with_cases
+
+A = "a"
+B = "b"
+C = "c"
+
+
+@case(tags=[A])
+def case_one():
+    return 1
+
+
+@case(tags=[A, B])
+def case_two():
+    return 2
+
+
+@case(tags=[B, C])
+def case_three():
+    return 3
+
+
+@case(tags=[A, C])
+def case_four():
+    return 4
+
+
+@parametrize_with_cases(
+    argnames="value", cases=".", filter=filters.has_tag(B)
+)
+def test_filter_with_tag(value):
+    print(value)
+
+
+@parametrize_with_cases(
+    argnames="value", cases=".", filter=~filters.has_tag(B)
+)
+def test_filter_without_tag(value):
+    print(value)
+
+
+@parametrize_with_cases(
+    argnames="value", cases=".", filter=filters.has_tag(B) & filters.has_tag(C)
+)
+def test_filter_with_and_relation(value):
+    print(value)
+
+
+@parametrize_with_cases(
+    argnames="value", cases=".", filter=filters.has_tag(B) | filters.has_tag(C)
+)
+def test_filter_with_or_relation(value):
+    print(value)
+
+
+@parametrize_with_cases(
+    argnames="value", cases=".", filter=filters.has_prefix("case_t")
+)
+def test_filter_with_prefix(value):
+    print(value)
+
+
+@parametrize_with_cases(
+    argnames="value", cases=".", filter=filters.has_suffix("e")
+)
+def test_filter_with_suffix(value):
+    print(value)