1 files changed, 57 insertions, 0 deletions
diff --git a/test/unit/test_c_api.cpp b/test/unit/test_c_api.cpp
index da95e523..9e477ef3 100644
--- a/test/unit/test_c_api.cpp
+++ b/test/unit/test_c_api.cpp
@@ -1600,6 +1600,63 @@ TEST_F(CApi, proj_create_operations_with_pivot) {
 
 // ---------------------------------------------------------------------------
 
+TEST_F(CApi, proj_create_operations_allow_ballpark_transformations) {
+    auto ctxt = proj_create_operation_factory_context(m_ctxt, nullptr);
+    ASSERT_NE(ctxt, nullptr);
+    ContextKeeper keeper_ctxt(ctxt);
+
+    auto source_crs = proj_create_from_database(
+        m_ctxt, "EPSG", "4267", PJ_CATEGORY_CRS, false, nullptr); // NAD27
+    ASSERT_NE(source_crs, nullptr);
+    ObjectKeeper keeper_source_crs(source_crs);
+
+    auto target_crs = proj_create_from_database(
+        m_ctxt, "EPSG", "4258", PJ_CATEGORY_CRS, false, nullptr); // ETRS89
+    ASSERT_NE(target_crs, nullptr);
+    ObjectKeeper keeper_target_crs(target_crs);
+
+    proj_operation_factory_context_set_spatial_criterion(
+        m_ctxt, ctxt, PROJ_SPATIAL_CRITERION_PARTIAL_INTERSECTION);
+
+    proj_operation_factory_context_set_grid_availability_use(
+        m_ctxt, ctxt, PROJ_GRID_AVAILABILITY_IGNORED);
+
+    // Default: allowed implictly
+    {
+        auto res = proj_create_operations(m_ctxt, source_crs, target_crs, ctxt);
+        ASSERT_NE(res, nullptr);
+        ObjListKeeper keeper_res(res);
+
+        EXPECT_EQ(proj_list_get_count(res), 1);
+    }
+
+    // Allow explictly
+    {
+        proj_operation_factory_context_set_allow_ballpark_transformations(
+            m_ctxt, ctxt, true);
+
+        auto res = proj_create_operations(m_ctxt, source_crs, target_crs, ctxt);
+        ASSERT_NE(res, nullptr);
+        ObjListKeeper keeper_res(res);
+
+        EXPECT_EQ(proj_list_get_count(res), 1);
+    }
+
+    // Disallow
+    {
+        proj_operation_factory_context_set_allow_ballpark_transformations(
+            m_ctxt, ctxt, false);
+
+        auto res = proj_create_operations(m_ctxt, source_crs, target_crs, ctxt);
+        ASSERT_NE(res, nullptr);
+        ObjListKeeper keeper_res(res);
+
+        EXPECT_EQ(proj_list_get_count(res), 0);
+    }
+}
+
+// ---------------------------------------------------------------------------
+
 TEST_F(CApi, proj_context_set_database_path_null) {
 
     EXPECT_TRUE(