test: add a test for annotated assignment

Every statement-level ast node should be tested. Annotated assignment
was missing.

Also, we don't need "exec" anymore, that was only for Python 2.

And: this is the 1000th test!

2 files changed, 19 insertions, 1 deletions

diff --git a/coverage/parser.py b/coverage/parser.py
index e4c86703..1c6e995a 100644
--- a/coverage/parser.py
+++ b/coverage/parser.py
@@ -708,7 +708,7 @@ class AstArcAnalyzer:
 
     # The node types that just flow to the next node with no complications.
     OK_TO_DEFAULT = {
-        "Assign", "Assert", "AugAssign", "Delete", "Exec", "Expr", "Global",
+        "AnnAssign", "Assign", "Assert", "AugAssign", "Delete", "Expr", "Global",
         "Import", "ImportFrom", "Nonlocal", "Pass",
     }
 
@@ -904,6 +904,9 @@ class AstArcAnalyzer:
     # also call self.add_arc to record arcs they find.  These functions mirror
     # the Python semantics of each syntactic construct.  See the docstring
     # for add_arcs to understand the concept of exits from a node.
+    #
+    # Every node type that represents a statement should have a handler, or it
+    # should be listed in OK_TO_DEFAULT.
 
     @contract(returns='ArcStarts')
     def _handle__Break(self, node):
diff --git a/tests/test_arcs.py b/tests/test_arcs.py
index 8bf83008..905430e6 100644
--- a/tests/test_arcs.py
+++ b/tests/test_arcs.py
@@ -1659,6 +1659,21 @@ class AsyncTest(CoverageTest):
         )
 
 
+class AnnotationTest(CoverageTest):
+    """Tests using type annotations."""
+
+    def test_annotations(self):
+        self.check_coverage("""\
+            def f(x:str, y:int) -> str:
+                a:int = 2
+                return f"{x}, {y}, {a}, 3"
+            print(f("x", 4))
+            """,
+            arcz=".1 .2 23 3.  14 4.",
+        )
+        assert self.stdout() == "x, 4, 2, 3\n"
+
+
 class ExcludeTest(CoverageTest):
     """Tests of exclusions to indicate known partial branches."""