From 44d0cd8d6243ec5b51980f3a69001b2535f49228 Mon Sep 17 00:00:00 2001
From: Steve Canny <stcanny@gmail.com>
Date: Mon, 4 May 2020 12:37:06 -0700
Subject: [PATCH] fix: add unit test for CubeSet._is_numeric_mean

---
 src/cr/cube/cube.py     |  1 +
 tests/unit/test_cube.py | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/cr/cube/cube.py b/src/cr/cube/cube.py
index db2fbd9c1..fe9c8833f 100644
--- a/src/cr/cube/cube.py
+++ b/src/cr/cube/cube.py
@@ -141,6 +141,7 @@ def _is_multi_cube(self):
         """True if more than one cube-response was provided on construction."""
         return len(self._cube_responses) > 1
 
+    @lazyproperty
     def _is_numeric_mean(self):
         """True when CubeSet is special-case "numeric-mean" case requiring inflation.
 
diff --git a/tests/unit/test_cube.py b/tests/unit/test_cube.py
index 81fc98618..0e65a18dc 100644
--- a/tests/unit/test_cube.py
+++ b/tests/unit/test_cube.py
@@ -167,6 +167,29 @@ def it_provides_access_to_its_Cube_objects_to_help(self, _iter_cubes_, cube_):
 
         assert cubes == (cube_, cube_, cube_)
 
+    @pytest.mark.parametrize(
+        ("is_multi_cube", "cube_0_ndim", "expected_value"),
+        ((False, 1, False), (False, 0, False), (True, 1, False), (True, 0, True)),
+    )
+    def it_knows_whether_it_is_numeric_mean_to_help(
+        self,
+        _is_multi_cube_prop_,
+        is_multi_cube,
+        Cube_,
+        cube_,
+        cube_0_ndim,
+        expected_value,
+    ):
+        _is_multi_cube_prop_.return_value = is_multi_cube
+        cube_.ndim = cube_0_ndim
+        Cube_.return_value = cube_
+        cube_set = CubeSet(({"cube": 0}, {"cube": 1}), None, None, None)
+
+        is_numeric_mean = cube_set._is_numeric_mean
+
+        assert Cube_.call_args_list == ([call({"cube": 0})] if is_multi_cube else [])
+        assert is_numeric_mean == expected_value
+
     def it_constructs_its_sequence_of_cube_objects_to_help(
         self, request, Cube_, _is_numeric_mean_prop_
     ):
@@ -263,6 +286,10 @@ def cube_(self, request):
     def _cubes_prop_(self, request):
         return property_mock(request, CubeSet, "_cubes")
 
+    @pytest.fixture
+    def _is_multi_cube_prop_(self, request):
+        return property_mock(request, CubeSet, "_is_multi_cube")
+
     @pytest.fixture
     def _is_numeric_mean_prop_(self, request):
         return property_mock(request, CubeSet, "_is_numeric_mean")