Add a unittest

pygmt/tests/test_clib_loading.py

@@ -11,6 +11,7 @@
 
 import pytest
 from pygmt.clib.loading import check_libgmt, clib_full_names, clib_names, load_libgmt
+from pygmt.clib.session import Session
 from pygmt.exceptions import GMTCLibError, GMTCLibNotFoundError, GMTOSError
 
 
@@ -208,6 +209,45 @@ def test_brokenlib_brokenlib_workinglib(self):
  assert check_libgmt(load_libgmt(lib_fullnames=lib_fullnames)) is None
 
 
+class TestLibgmtCount:
+ """
+ Test that the GMT library is not repeatly loaded in every session.
+ """
+
+ loaded_libgmt = load_libgmt() # Load the GMT library and reuse it when necessary
+ counter = 0 # Count how many times ctypes.CDLL is called
+
+ def _mock_ctypes_cdll_return(self, libname): # noqa: ARG002
+ """
+ Mock ctypes.CDLL to count how many times the function is called.
+
+ If ctypes.CDLL is called, the counter increases by one.
+ """
+ self.counter += 1 # Increase the counter
+ return self.loaded_libgmt
+
+ @pytest.fixture()
+ def _mock_ctypes(self, monkeypatch):
+ monkeypatch.setattr(ctypes, "CDLL", self._mock_ctypes_cdll_return)
+
+ @pytest.mark.usefixtures("_mock_ctypes")
+ def test_libgmt_load_counter(self):
+ """
+ Make sure that the GMT library is not loaded in every session.
+ """
+ with Session() as lib:
+ _ = lib
+ with Session() as lib:
+ _ = lib
+ assert self.counter == 0 # ctypes.CDLL is not called after two sessions.
+
+ # Explicitly calling load_libgmt to make sure the mock function is correct
+ load_libgmt()
+ assert self.counter == 1
+ load_libgmt()
+ assert self.counter == 2
+
+
 ###############################################################################
 # Test clib_full_names
 @pytest.fixture(scope="module", name="gmt_lib_names")