Improve tests

pygmt/tests/test_tilemap.py

@@ -2,14 +2,24 @@
 Test Figure.tilemap.
 """
 
+import importlib
+from unittest.mock import patch
+
 import pytest
 from pygmt import Figure
 
-contextily = pytest.importorskip("contextily")
-rioxarray = pytest.importorskip("rioxarray")
+try:
+    import contextily
+
+    _HAS_CONTEXTILY = True
+except ImportError:
+    _HAS_CONTEXTILY = False
+
+_HAS_RIOXARRAY = bool(importlib.util.find_spec("rioxarray"))
 
 
 @pytest.mark.mpl_image_compare
+@pytest.mark.skipif(not _HAS_CONTEXTILY, reason="contextily is not installed")
 def test_tilemap_web_mercator():
     """
     Create a tilemap plot in Spherical Mercator projection (EPSG:3857).
@@ -27,6 +37,10 @@ def test_tilemap_web_mercator():
 
 @pytest.mark.benchmark
 @pytest.mark.mpl_image_compare
+@pytest.mark.skipif(
+    not (_HAS_CONTEXTILY and _HAS_RIOXARRAY),
+    reason="contextily and rioxarray are not installed",
+)
 def test_tilemap_ogc_wgs84():
     """
     Create a tilemap plot using longitude/latitude coordinates (OGC:WGS84), centred on
@@ -45,6 +59,10 @@ def test_tilemap_ogc_wgs84():
 
 @pytest.mark.mpl_image_compare
 @pytest.mark.parametrize("no_clip", [False, True])
+@pytest.mark.skipif(
+    not (_HAS_CONTEXTILY and _HAS_RIOXARRAY),
+    reason="contextily and rioxarray are not installed",
+)
 def test_tilemap_no_clip(no_clip):
     """
     Create a tilemap plot clipped to the Southern Hemisphere when no_clip is False, but
@@ -60,3 +78,34 @@ def test_tilemap_no_clip(no_clip):
         no_clip=no_clip,
     )
     return fig
+
+
+@pytest.mark.skipif(_HAS_CONTEXTILY, reason="contextily is installed.")
+def test_tilemap_no_contextily():
+    """
+    Raise an ImportError when contextily is not installed.
+    """
+    fig = Figure()
+    with pytest.raises(ImportError, match="Package `contextily` is required"):
+        fig.tilemap(
+            region=[-20000000.0, 20000000.0, -20000000.0, 20000000.0],
+            zoom=0,
+            lonlat=False,
+            frame="afg",
+        )
+
+
+@pytest.mark.skipif(_HAS_RIOXARRAY, reason="rioxarray is installed.")
+def test_tilemap_no_rioxarray():
+    """
+    Raise an ImportError when rioxarray is not installed and contextily is installed.
+    """
+    fig = Figure()
+    # In our CI, contextily and rioxarray are installed together, so we will see the
+    # error about contextily, not rioxarray. Here we mock contextily as installed, to
+    # make sure that we see the rioxarray error message when rioxarray is not installed.
+    with patch("pygmt.datasets.tile_map._HAS_CONTEXTILY", True):
+        with pytest.raises(ImportError, match="Package `rioxarray` is required"):
+            fig.tilemap(
+                region=[-180.0, 180.0, -90, 90], zoom=0, lonlat=True, frame="afg"
+            )