Support exclusion rules in combinations

Like py.test we need to be able to mark certain combination
elements with exclusion rules.   Add additional logic
to pytestlplugin and exclusions so that the exclusion decorators
can be added to the combination tuples, where they will be applied
to the decorated function along with a qualifier that the test
arguments need to match what's given.

Change-Id: I15d2839954d77a252bab5aaf6e3fd9f388c99dd5

2 files changed, 73 insertions, 12 deletions

diff --git a/lib/sqlalchemy/testing/exclusions.py b/lib/sqlalchemy/testing/exclusions.py
index 8f63fcbf8..86f3b7aac 100644
--- a/lib/sqlalchemy/testing/exclusions.py
+++ b/lib/sqlalchemy/testing/exclusions.py
@@ -35,10 +35,20 @@ class compound(object):
         self.fails = set()
         self.skips = set()
         self.tags = set()
+        self.combinations = {}
 
     def __add__(self, other):
         return self.add(other)
 
+    def with_combination(self, **kw):
+        copy = compound()
+        copy.fails.update(self.fails)
+        copy.skips.update(self.skips)
+        copy.tags.update(self.tags)
+        copy.combinations.update((f, kw) for f in copy.fails)
+        copy.combinations.update((s, kw) for s in copy.skips)
+        return copy
+
     def add(self, *others):
         copy = compound()
         copy.fails.update(self.fails)
@@ -85,6 +95,7 @@ class compound(object):
         self.skips.update(other.skips)
         self.fails.update(other.fails)
         self.tags.update(other.tags)
+        self.combinations.update(other.combinations)
 
     def __call__(self, fn):
         if hasattr(fn, "_sa_exclusion_extend"):
@@ -107,43 +118,63 @@ class compound(object):
         try:
             yield
         except Exception as ex:
-            all_fails._expect_failure(config._current, ex)
+            all_fails._expect_failure(config._current, ex, None)
         else:
-            all_fails._expect_success(config._current)
+            all_fails._expect_success(config._current, None)
+
+    def _check_combinations(self, combination, predicate):
+        if predicate in self.combinations:
+            for k, v in combination:
+                if (
+                    k in self.combinations[predicate]
+                    and self.combinations[predicate][k] != v
+                ):
+                    return False
+        return True
 
     def _do(self, cfg, fn, *args, **kw):
+        if len(args) > 1:
+            insp = inspect_getfullargspec(fn)
+            combination = list(zip(insp.args[1:], args[1:]))
+        else:
+            combination = None
+
         for skip in self.skips:
-            if skip(cfg):
+            if self._check_combinations(combination, skip) and skip(cfg):
                 msg = "'%s' : %s" % (fn.__name__, skip._as_string(cfg))
                 config.skip_test(msg)
 
         try:
             return_value = fn(*args, **kw)
         except Exception as ex:
-            self._expect_failure(cfg, ex, name=fn.__name__)
+            self._expect_failure(cfg, ex, combination, name=fn.__name__)
         else:
-            self._expect_success(cfg, name=fn.__name__)
+            self._expect_success(cfg, combination, name=fn.__name__)
             return return_value
 
-    def _expect_failure(self, config, ex, name="block"):
+    def _expect_failure(self, config, ex, combination, name="block"):
         for fail in self.fails:
-            if fail(config):
+            if self._check_combinations(combination, fail) and fail(config):
+                if util.py2k:
+                    str_ex = unicode(ex).encode("utf-8", errors="ignore")
+                else:
+                    str_ex = str(ex)
                 print(
                     (
                         "%s failed as expected (%s): %s "
-                        % (name, fail._as_string(config), str(ex))
+                        % (name, fail._as_string(config), str_ex)
                     )
                 )
                 break
         else:
             util.raise_from_cause(ex)
 
-    def _expect_success(self, config, name="block"):
+    def _expect_success(self, config, combination, name="block"):
         if not self.fails:
             return
 
         for fail in self.fails:
-            if fail(config):
+            if self._check_combinations(combination, fail) and fail(config):
                 raise AssertionError(
                     "Unexpected success for '%s' (%s)"
                     % (
diff --git a/lib/sqlalchemy/testing/plugin/pytestplugin.py b/lib/sqlalchemy/testing/plugin/pytestplugin.py
index de0f8862a..2f7df97fa 100644
--- a/lib/sqlalchemy/testing/plugin/pytestplugin.py
+++ b/lib/sqlalchemy/testing/plugin/pytestplugin.py
@@ -315,6 +315,7 @@ class PytestFixtureFunctions(plugin_base.FixtureFunctions):
         ids for parameter sets are derived using an optional template.
 
         """
+        from sqlalchemy.testing import exclusions
 
         if sys.version_info.major == 3:
             if len(arg_sets) == 1 and hasattr(arg_sets[0], "__next__"):
@@ -325,6 +326,22 @@ class PytestFixtureFunctions(plugin_base.FixtureFunctions):
 
         argnames = kw.pop("argnames", None)
 
+        exclusion_combinations = []
+
+        def _filter_exclusions(args):
+            result = []
+            gathered_exclusions = []
+            for a in args:
+                if isinstance(a, exclusions.compound):
+                    gathered_exclusions.append(a)
+                else:
+                    result.append(a)
+
+            exclusion_combinations.extend(
+                [(exclusion, result) for exclusion in gathered_exclusions]
+            )
+            return result
+
         id_ = kw.pop("id_", None)
 
         if id_:
@@ -348,7 +365,7 @@ class PytestFixtureFunctions(plugin_base.FixtureFunctions):
             ]
             arg_sets = [
                 pytest.param(
-                    *_arg_getter(arg)[1:],
+                    *_arg_getter(_filter_exclusions(arg))[1:],
                     id="-".join(
                         comb_fn(getter(arg)) for getter, comb_fn in fns
                     )
@@ -359,7 +376,9 @@ class PytestFixtureFunctions(plugin_base.FixtureFunctions):
             # ensure using pytest.param so that even a 1-arg paramset
             # still needs to be a tuple.  otherwise paramtrize tries to
             # interpret a single arg differently than tuple arg
-            arg_sets = [pytest.param(*arg) for arg in arg_sets]
+            arg_sets = [
+                pytest.param(*_filter_exclusions(arg)) for arg in arg_sets
+            ]
 
         def decorate(fn):
             if inspect.isclass(fn):
@@ -372,6 +391,17 @@ class PytestFixtureFunctions(plugin_base.FixtureFunctions):
                     _argnames = getargspec(fn).args[1:]
                 else:
                     _argnames = argnames
+
+                if exclusion_combinations:
+                    for exclusion, combination in exclusion_combinations:
+                        combination_by_kw = {
+                            argname: val
+                            for argname, val in zip(_argnames, combination)
+                        }
+                        exclusion = exclusion.with_combination(
+                            **combination_by_kw
+                        )
+                        fn = exclusion(fn)
                 return pytest.mark.parametrize(_argnames, arg_sets)(fn)
 
         return decorate