Add test units for visualizion utilities

pyresample/test/test_boundary/test_sides.py

@@ -18,8 +18,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """Test the BoundarySides objects."""
 
-import pytest
 import numpy as np
+import pytest
+
 from pyresample.boundary.sides import BoundarySides
 
 

pyresample/test/test_visualization/test_geometries.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# pyresample, Resampling of remote sensing image data in python
+#
+# Copyright (C) 2010-2022 Pyresample developers
+#
+# This program is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option) any
+# later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""Test cartopy plotting utilities."""
+
+import pytest
+import matplotlib.pyplot as plt
+import cartopy.crs as ccrs
+from shapely.geometry import Polygon 
+from pyresample.visualization.geometries import (
+    _add_map_background, 
+    _check_subplot_kw, 
+    _initialize_plot, 
+    plot_geometries,
+)
+
+
+class TestPlotFunctions:
+    """Test suite for the provided plotting functions."""
+
+    def test_add_map_background(self):
+        """Test adding a map background to an axis."""
+        fig, ax = plt.subplots(subplot_kw={'projection': ccrs.PlateCarree()})
+        result_ax = _add_map_background(ax)
+        assert isinstance(result_ax, plt.Axes)
+
+    def test_check_subplot_kw_valid(self):
+        """Test _check_subplot_kw with valid input."""
+        valid_kw = {'projection': ccrs.PlateCarree()}
+        assert _check_subplot_kw(valid_kw) == valid_kw
+
+    def test_check_subplot_kw_none(self):
+        """Test _check_subplot_kw with None input."""
+        assert 'projection' in _check_subplot_kw(None)
+
+    def test_check_subplot_kw_invalid(self):
+        """Test _check_subplot_kw with invalid input."""
+        with pytest.raises(TypeError):
+            _check_subplot_kw("invalid")
+
+        with pytest.raises(TypeError):
+            _check_subplot_kw(2)
+
+        with pytest.raises(TypeError):
+            _check_subplot_kw([2])
+
+        with pytest.raises(ValueError):
+            _check_subplot_kw({})
+
+    def test_initialize_plot_with_ax(self):
+        """Test _initialize_plot with an existing ax."""
+        fig, ax = plt.subplots()
+        _, result_ax, initialized_here = _initialize_plot(ax=ax)
+        assert result_ax == ax
+        assert not initialized_here
+
+    @pytest.mark.parametrize("ax_provided", [True, False])
+    def test_plot_geometries(self, ax_provided):
+        """Test plot_geometries function returns the correct type based on ax_provided."""
+        vertices1 = [(0,0),(0,1), (1, 0)]
+        vertices2 = [(0,0),(0,2), (2, 0)]
+        geometries = [Polygon(vertices1), Polygon(vertices2)]
+        crs = ccrs.PlateCarree()
+        ax = plt.axes(projection=crs) if ax_provided else None
+        result = plot_geometries(geometries, crs, ax=ax)
+
+        if ax_provided:
+            assert isinstance(result, plt.Axes)
+        else:
+            assert isinstance(result, plt.Figure)
+
+