Merge pull request #32459 from mantidproject/27753_AdjustUnitTestForGeneratePointInObject

Add extra unit test for case where point generation misses

Framework/Geometry/test/CSGObjectTest.h

@@ -1314,19 +1314,42 @@ public:
     EXPECT_CALL(rng, nextValue()).InSequence(rand).WillOnce(Return(randZ));
 
     constexpr double halfWidth{0.75};
-    auto ball = ComponentCreationHelper::createCuboid(halfWidth);
+    auto cuboid = ComponentCreationHelper::createCuboid(halfWidth);
     // Create a thin infinite rectangular region to restrict point generation
     BoundingBox activeRegion(0.1, 0.1, 0.1, -0.1, -0.1, -0.1);
     constexpr size_t maxAttempts{1};
-    boost::optional<V3D> point = ball->generatePointInObject(rng, activeRegion, maxAttempts);
+    boost::optional<V3D> point = cuboid->generatePointInObject(rng, activeRegion, maxAttempts);
     TS_ASSERT_EQUALS(!point, false);
-    // We should get the point generated from the second 'random' triplet.
     constexpr double tolerance{1e-10};
     TS_ASSERT_DELTA(-0.1 + randX * 0.2, point->X(), tolerance)
     TS_ASSERT_DELTA(-0.1 + randY * 0.2, point->Y(), tolerance)
     TS_ASSERT_DELTA(-0.1 + randZ * 0.2, point->Z(), tolerance)
   }
 
+  void testGeneratePointSometimesMisses() {
+    // if there's a requirement to fairly sample scatter points between different sample environment
+    // parts then it's important the generatePointInObject method misses sometimes
+    using namespace ::testing;
+
+    // Generate "random" sequence.
+    MockRNG rng;
+    Sequence rand;
+    constexpr double randX{0.92};
+    constexpr double randY{0.14};
+    constexpr double randZ{0.83};
+    EXPECT_CALL(rng, nextValue()).InSequence(rand).WillOnce(Return(randX));
+    EXPECT_CALL(rng, nextValue()).InSequence(rand).WillOnce(Return(randY));
+    EXPECT_CALL(rng, nextValue()).InSequence(rand).WillOnce(Return(randZ));
+
+    constexpr double halfWidth{0.075};
+    auto cuboid = ComponentCreationHelper::createCuboid(halfWidth);
+    // Create a rectangular region to restrict point generation
+    BoundingBox activeRegion(0.1, 0.1, 0.1, -0.1, -0.1, -0.1);
+    constexpr size_t maxAttempts{1};
+    boost::optional<V3D> point = cuboid->generatePointInObject(rng, activeRegion, maxAttempts);
+    TS_ASSERT_EQUALS(!point, true);
+  }
+
   void testSolidAngleSphere()
   /**
   Test solid angle calculation for a sphere