Merge pull request #5361 from asottile/backport_5360

[4.6] Fix all() unroll for non-generators/non-list comprehensions (#5360)

Author: asottile

changelog/5358.bugfix.rst

@@ -0,0 +1 @@
+Fix assertion rewriting of ``all()`` calls to deal with non-generators.

src/_pytest/assertion/rewrite.py

@@ -949,11 +949,21 @@ def visit_BinOp(self, binop):
         res = self.assign(ast.BinOp(left_expr, binop.op, right_expr))
         return res, explanation
 
+    @staticmethod
+    def _is_any_call_with_generator_or_list_comprehension(call):
+        """Return True if the Call node is an 'any' call with a generator or list comprehension"""
+        return (
+            isinstance(call.func, ast.Name)
+            and call.func.id == "all"
+            and len(call.args) == 1
+            and isinstance(call.args[0], (ast.GeneratorExp, ast.ListComp))
+        )
+
     def visit_Call_35(self, call):
         """
         visit `ast.Call` nodes on Python3.5 and after
         """
-        if isinstance(call.func, ast.Name) and call.func.id == "all":
+        if self._is_any_call_with_generator_or_list_comprehension(call):
             return self._visit_all(call)
         new_func, func_expl = self.visit(call.func)
         arg_expls = []
@@ -980,8 +990,6 @@ def visit_Call_35(self, call):
 
     def _visit_all(self, call):
         """Special rewrite for the builtin all function, see #5062"""
-        if not isinstance(call.args[0], (ast.GeneratorExp, ast.ListComp)):
-            return
         gen_exp = call.args[0]
         assertion_module = ast.Module(
             body=[ast.Assert(test=gen_exp.elt, lineno=1, msg="", col_offset=1)]
@@ -1009,7 +1017,7 @@ def visit_Call_legacy(self, call):
         """
         visit `ast.Call nodes on 3.4 and below`
         """
-        if isinstance(call.func, ast.Name) and call.func.id == "all":
+        if self._is_any_call_with_generator_or_list_comprehension(call):
             return self._visit_all(call)
         new_func, func_expl = self.visit(call.func)
         arg_expls = []

testing/test_assertrewrite.py

@@ -677,7 +677,7 @@ def __repr__(self):
         assert "UnicodeDecodeError" not in msg
         assert "UnicodeEncodeError" not in msg
 
-    def test_unroll_generator(self, testdir):
+    def test_unroll_all_generator(self, testdir):
         testdir.makepyfile(
             """
             def check_even(num):
@@ -692,7 +692,7 @@ def test_generator():
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(["*assert False*", "*where False = check_even(1)*"])
 
-    def test_unroll_list_comprehension(self, testdir):
+    def test_unroll_all_list_comprehension(self, testdir):
         testdir.makepyfile(
             """
             def check_even(num):
@@ -707,6 +707,31 @@ def test_list_comprehension():
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(["*assert False*", "*where False = check_even(1)*"])
 
+    def test_unroll_all_object(self, testdir):
+        """all() for non generators/non list-comprehensions (#5358)"""
+        testdir.makepyfile(
+            """
+            def test():
+                assert all((1, 0))
+            """
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(["*assert False*", "*where False = all((1, 0))*"])
+
+    def test_unroll_all_starred(self, testdir):
+        """all() for non generators/non list-comprehensions (#5358)"""
+        testdir.makepyfile(
+            """
+            def test():
+                x = ((1, 0),)
+                assert all(*x)
+            """
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(
+            ["*assert False*", "*where False = all(*((1, 0),))*"]
+        )
+
     def test_for_loop(self, testdir):
         testdir.makepyfile(
             """