From 8cf157b24a07d3e714392518f5efc3c2e417d396 Mon Sep 17 00:00:00 2001
From: Joe Wallwork <jw2423@cam.ac.uk>
Date: Tue, 13 Jan 2026 16:43:03 +0000
Subject: [PATCH] Change ReadDiagnostic test to use 3 ranks

---
 core/test/CMakeLists.txt              | 12 ++++++------
 core/test/XiosReadDiagnostic_test.cpp |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/core/test/CMakeLists.txt b/core/test/CMakeLists.txt
index 8fc98d746..b37b2cd03 100644
--- a/core/test/CMakeLists.txt
+++ b/core/test/CMakeLists.txt
@@ -233,21 +233,21 @@ if(ENABLE_MPI)
         )
         target_link_libraries(testXiosReadForcing_MPI2 PRIVATE nextsimlib doctest::doctest)
 
-        add_executable(testXiosReadDiagnostic_MPI2 "XiosReadDiagnostic_test.cpp" "MainMPI.cpp")
-        target_compile_definitions(testXiosReadDiagnostic_MPI2
+        add_executable(testXiosReadDiagnostic_MPI3 "XiosReadDiagnostic_test.cpp" "MainMPI.cpp")
+        target_compile_definitions(testXiosReadDiagnostic_MPI3
             PRIVATE
                 USE_XIOS
                 TEST_FILES_DIR=\"${CMAKE_CURRENT_BINARY_DIR}\"
         )
         target_include_directories(
-            testXiosReadDiagnostic_MPI2
+            testXiosReadDiagnostic_MPI3
             PRIVATE
                 ${PHYSICS_INCLUDE_DIRS}
                 "${MODEL_INCLUDE_DIR}"
                 "${XIOS_INCLUDE_LIST}"
                 "${ModulesRoot}/StructureModule"
         )
-        target_link_libraries(testXiosReadDiagnostic_MPI2 PRIVATE nextsimlib doctest::doctest)
+        target_link_libraries(testXiosReadDiagnostic_MPI3 PRIVATE nextsimlib doctest::doctest)
 
         add_executable(testXiosReadRestart_MPI2 "XiosReadRestart_test.cpp" "MainMPI.cpp")
         target_compile_definitions(testXiosReadRestart_MPI2
@@ -302,7 +302,7 @@ if(ENABLE_MPI)
             testXiosAxis_MPI3
             testXiosField_MPI3
             testXiosReadForcing_MPI2
-            testXiosReadDiagnostic_MPI2
+            testXiosReadDiagnostic_MPI3
             testXiosReadRestart_MPI2
             testXiosWriteDiagnostic_MPI2
             testXiosWriteRestart_MPI2
@@ -312,7 +312,7 @@ if(ENABLE_MPI)
 
         # Ensure XiosWrite<Diagnostic/Restart>_test are run before XiosRead<Diagnostic/Restart>_test
         set_tests_properties(testXiosReadRestart_MPI2 PROPERTIES DEPENDS testXiosWriteRestart_MPI2)
-        set_tests_properties(testXiosReadDiagnostic_MPI2
+        set_tests_properties(testXiosReadDiagnostic_MPI3
                              PROPERTIES DEPENDS testXiosWriteDiagnostic_MPI2)
     else()
         add_executable(testHaloExchangeCB_MPI3
diff --git a/core/test/XiosReadDiagnostic_test.cpp b/core/test/XiosReadDiagnostic_test.cpp
index 7c4658d86..d3a0e4116 100644
--- a/core/test/XiosReadDiagnostic_test.cpp
+++ b/core/test/XiosReadDiagnostic_test.cpp
@@ -34,7 +34,7 @@ namespace Nextsim {
  * 2. Test the file writing functionality via `writeDiagnosticTime` in the sense of checking that
  *    time-averaging is applied.
  */
-MPI_TEST_CASE("TestXiosReadDiagnostic", 2)
+MPI_TEST_CASE("TestXiosReadDiagnostic", 3)
 {
     std::stringstream config;
     config << "[model]" << std::endl;
@@ -43,7 +43,7 @@ MPI_TEST_CASE("TestXiosReadDiagnostic", 2)
     config << "time_step = P0-0T01:30:00" << std::endl;
     config << "init_file = " << diagnosticFilename << std::endl;
     config << "restart_period = P0-0T03:00:00" << std::endl;
-    config << "partition_file = xios_test_partition_metadata_2.nc" << std::endl;
+    config << "partition_file = xios_test_partition_metadata_3.nc" << std::endl;
     config << "[XiosInput]" << std::endl;
     config << "field_names = " << hsnowName << std::endl;
     config << "period = P0-0T03:00:00" << std::endl;