From 27519dd41adc9e9a9704018a5e8c05d2f8926f02 Mon Sep 17 00:00:00 2001
From: Eric Cousineau <eric.cousineau@tri.global>
Date: Thu, 24 Dec 2020 13:53:36 -0600
Subject: [PATCH 1/2] test_eval: Show example of working closure

---
 tests/test_eval.cpp | 12 ++++++++++++
 tests/test_eval.py  |  5 +++++
 2 files changed, 17 insertions(+)

diff --git a/tests/test_eval.cpp b/tests/test_eval.cpp
index 5416c2ec4d..6cbcdeda71 100644
--- a/tests/test_eval.cpp
+++ b/tests/test_eval.cpp
@@ -15,6 +15,7 @@ TEST_SUBMODULE(eval_, m) {
     // test_evals
 
     auto global = py::dict(py::module_::import("__main__").attr("__dict__"));
+    py::handle copy = py::module::import("copy").attr("copy");
 
     m.def("test_eval_statements", [global]() {
         auto local = py::dict();
@@ -96,4 +97,15 @@ TEST_SUBMODULE(eval_, m) {
         auto int_class = py::eval("isinstance(42, int)", global);
         return global;
     });
+
+    m.def("test_eval_closure", [global, copy]() {
+        py::dict local = copy(global);
+        py::exec(R"(
+            closure_value = 10
+
+            def func():
+                return closure_value
+            )", local, local);
+        return local;
+    });
 }
diff --git a/tests/test_eval.py b/tests/test_eval.py
index 1bb05af05e..1c25eb094c 100644
--- a/tests/test_eval.py
+++ b/tests/test_eval.py
@@ -33,3 +33,8 @@ def test_eval_empty_globals():
     g = {}
     assert "__builtins__" in m.eval_empty_globals(g)
     assert "__builtins__" in g
+
+
+def test_eval_closure():
+    local = m.test_eval_closure()
+    assert local["func"]() == 10

From 649a1e7da9faefe681d6834063ae223e3ba64e01 Mon Sep 17 00:00:00 2001
From: Yannick Jadoul <yannick.jadoul@belgacom.net>
Date: Mon, 25 Jan 2021 01:32:22 +0100
Subject: [PATCH 2/2] Extend test_eval_closure with weirder examples of
 closures for py::eval

---
 tests/test_eval.cpp | 20 +++++++++++++-------
 tests/test_eval.py  | 16 ++++++++++++++--
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/tests/test_eval.cpp b/tests/test_eval.cpp
index 6cbcdeda71..160a2f941a 100644
--- a/tests/test_eval.cpp
+++ b/tests/test_eval.cpp
@@ -15,7 +15,6 @@ TEST_SUBMODULE(eval_, m) {
     // test_evals
 
     auto global = py::dict(py::module_::import("__main__").attr("__dict__"));
-    py::handle copy = py::module::import("copy").attr("copy");
 
     m.def("test_eval_statements", [global]() {
         auto local = py::dict();
@@ -98,14 +97,21 @@ TEST_SUBMODULE(eval_, m) {
         return global;
     });
 
-    m.def("test_eval_closure", [global, copy]() {
-        py::dict local = copy(global);
+    // test_eval_closure
+    m.def("test_eval_closure", []() {
+        py::dict global;
+        global["closure_value"] = 42;
+        py::dict local;
+        local["closure_value"] = 0;
         py::exec(R"(
-            closure_value = 10
+            local_value = closure_value
 
-            def func():
+            def func_global():
                 return closure_value
-            )", local, local);
-        return local;
+
+            def func_local():
+                return local_value
+            )", global, local);
+        return std::make_pair(global, local);
     });
 }
diff --git a/tests/test_eval.py b/tests/test_eval.py
index 1c25eb094c..601e526f43 100644
--- a/tests/test_eval.py
+++ b/tests/test_eval.py
@@ -36,5 +36,17 @@ def test_eval_empty_globals():
 
 
 def test_eval_closure():
-    local = m.test_eval_closure()
-    assert local["func"]() == 10
+    global_, local = m.test_eval_closure()
+
+    assert global_["closure_value"] == 42
+    assert local["closure_value"] == 0
+
+    assert "local_value" not in global_
+    assert local["local_value"] == 0
+
+    assert "func_global" not in global_
+    assert local["func_global"]() == 42
+
+    assert "func_local" not in global_
+    with pytest.raises(NameError):
+        local["func_local"]()