Module docstrings in 3.7 are not part of Module node anymore

changelog/3530.trivial.rst

@@ -0,0 +1 @@
+Fix if in tests to support 3.7.0b5, where a docstring handling in AST got reverted.

testing/test_assertrewrite.py

@@ -65,18 +65,35 @@ def getmsg(f, extra_ns=None, must_pass=False):
             pytest.fail("function didn't raise at all")
 
 
+def adjust_body_for_new_docstring_in_module_node(m):
+    """Module docstrings in 3.8 are part of Module node.
+    This was briefly in 3.7 as well but got reverted in beta 5.
+
+    It's not in the body so we remove it so the following body items have
+    the same indexes on all Python versions:
+
+    TODO:
+
+    We have a complicated sys.version_info if in here to ease testing on
+    various Python 3.7 versions, but we should remove the 3.7 check after
+    3.7 is released as stable to make this check more straightforward.
+    """
+    if (
+        sys.version_info < (3, 8)
+        and not ((3, 7) <= sys.version_info <= (3, 7, 0, "beta", 4))
+    ):
+        assert len(m.body) > 1
+        assert isinstance(m.body[0], ast.Expr)
+        assert isinstance(m.body[0].value, ast.Str)
+        del m.body[0]
+
+
 class TestAssertionRewrite(object):
 
     def test_place_initial_imports(self):
         s = """'Doc string'\nother = stuff"""
         m = rewrite(s)
-        # Module docstrings in 3.7 are part of Module node, it's not in the body
-        # so we remove it so the following body items have the same indexes on
-        # all Python versions
-        if sys.version_info < (3, 7):
-            assert isinstance(m.body[0], ast.Expr)
-            assert isinstance(m.body[0].value, ast.Str)
-            del m.body[0]
+        adjust_body_for_new_docstring_in_module_node(m)
         for imp in m.body[0:2]:
             assert isinstance(imp, ast.Import)
             assert imp.lineno == 2
@@ -92,21 +109,15 @@ def test_place_initial_imports(self):
         assert isinstance(m.body[3], ast.Expr)
         s = """'doc string'\nfrom __future__ import with_statement"""
         m = rewrite(s)
-        if sys.version_info < (3, 7):
-            assert isinstance(m.body[0], ast.Expr)
-            assert isinstance(m.body[0].value, ast.Str)
-            del m.body[0]
+        adjust_body_for_new_docstring_in_module_node(m)
         assert isinstance(m.body[0], ast.ImportFrom)
         for imp in m.body[1:3]:
             assert isinstance(imp, ast.Import)
             assert imp.lineno == 2
             assert imp.col_offset == 0
         s = """'doc string'\nfrom __future__ import with_statement\nother"""
         m = rewrite(s)
-        if sys.version_info < (3, 7):
-            assert isinstance(m.body[0], ast.Expr)
-            assert isinstance(m.body[0].value, ast.Str)
-            del m.body[0]
+        adjust_body_for_new_docstring_in_module_node(m)
         assert isinstance(m.body[0], ast.ImportFrom)
         for imp in m.body[1:3]:
             assert isinstance(imp, ast.Import)
@@ -124,13 +135,8 @@ def test_place_initial_imports(self):
     def test_dont_rewrite(self):
         s = """'PYTEST_DONT_REWRITE'\nassert 14"""
         m = rewrite(s)
-        if sys.version_info < (3, 7):
-            assert len(m.body) == 2
-            assert isinstance(m.body[0], ast.Expr)
-            assert isinstance(m.body[0].value, ast.Str)
-            del m.body[0]
-        else:
-            assert len(m.body) == 1
+        adjust_body_for_new_docstring_in_module_node(m)
+        assert len(m.body) == 1
         assert m.body[0].msg is None
 
     def test_dont_rewrite_plugin(self, testdir):