Handle setting special parameters without default settings for config

pygmt/modules.py

@@ -163,9 +163,36 @@ class config:  # pylint: disable=invalid-name
     def __init__(self, **kwargs):
         # Save values so that we can revert to their initial values
         self.old_defaults = {}
+        self.special_params = {
+            "FONT": [
+                "FONT_ANNOT_PRIMARY",
+                "FONT_ANNOT_SECONDARY",
+                "FONT_HEADING",
+                "FONT_LABEL",
+                "FONT_TAG",
+                "FONT_TITLE",
+            ],
+            "FONT_ANNOT": ["FONT_ANNOT_PRIMARY", "FONT_ANNOT_SECONDARY"],
+            "FORMAT_TIME_MAP": ["FORMAT_TIME_PRIMARY_MAP", "FORMAT_TIME_SECONDARY_MAP"],
+            "MAP_ANNOT_OFFSET": [
+                "MAP_ANNOT_OFFSET_PRIMARY",
+                "MAP_ANNOT_OFFSET_SECONDARY",
+            ],
+            "MAP_GRID_CROSS_SIZE": [
+                "MAP_GRID_CROSS_SIZE_PRIMARY",
+                "MAP_GRID_CROSS_SIZE_SECONDARY",
+            ],
+            "MAP_GRID_PEN": ["MAP_GRID_PEN_PRIMARY", "MAP_GRID_PEN_SECONDARY"],
+            "MAP_TICK_LENGTH": ["MAP_TICK_LENGTH_PRIMARY", "MAP_TICK_LENGTH_SECONDARY"],
+            "MAP_TICK_PEN": ["MAP_TICK_PEN_PRIMARY", "MAP_TICK_PEN_SECONDARY"],
+        }
         with Session() as lib:
             for key in kwargs:
-                self.old_defaults[key] = lib.get_default(key)
+                if key in self.special_params:
+                    for k in self.special_params[key]:
+                        self.old_defaults[k] = lib.get_default(k)
+                else:
+                    self.old_defaults[key] = lib.get_default(key)
 
         # call gmt set to change GMT defaults
         arg_str = " ".join(

pygmt/tests/test_config.py

@@ -35,3 +35,135 @@ def test_config():
     # Revert to default settings
     config(FONT_ANNOT_PRIMARY="black")
     return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_font_one():
+    """
+    Test that setting `FONT` config changes all `FONT_*` settings except
+    `FONT_LOGO`. Specifically, this test only checks that `FONT_ANNOT_PRIMARY`,
+    `FONT_ANNOT_SECONDARY`, `FONT_LABEL`, and `FONT_TITLE` are modified.
+    """
+    fig = Figure()
+    with config(FONT="8p,red"):
+        fig.basemap(region=[0, 9, 0, 9], projection="C3/3/9c", T="mjTL+w4c+d4.5+l")
+    fig.basemap(T="mjBR+w5c+d-4.5+l")
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_font_annot():
+    """
+    Test that setting `FONT_ANNOT` config changes both `FONT_ANNOT_PRIMARY` and
+    `FONT_ANNOT_SECONDARY`.
+    """
+    fig = Figure()
+    with config(FONT_ANNOT="6p,red"):
+        fig.basemap(region=[0, 9, 0, 9], projection="C3/3/9c", T="mjTL+w4c+d4.5")
+    fig.basemap(T="mjBR+w5c+d-4.5")
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_format_time_map():
+    """
+    Test that setting `FORMAT_TIME_MAP` config changes both
+    `FORMAT_TIME_PRIMARY_MAP` and `FORMAT_TIME_SECONDARY_MAP`.
+    """
+    fig = Figure()
+    with config(FORMAT_TIME_MAP="abbreviation"):
+        fig.basemap(
+            region=["2020-1-24T", "2020-1-27T", 0, 1],
+            projection="X6c/1c",
+            frame=["pa1K", "sa1K", "NWse"],
+        )
+    fig.basemap(frame=["pa1K", "sa1K", "nwSE"])
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_map_annot_offset():
+    """
+    Test that setting `MAP_ANNOT_OFFSET` config changes both
+    `MAP_ANNOT_OFFSET_PRIMARY` and `MAP_ANNOT_OFFSET_SECONDARY`.
+    """
+    fig = Figure()
+    with config(MAP_ANNOT_OFFSET="15p"):
+        fig.basemap(
+            region=["2020-1-24T", "2020-1-27T", 0, 1],
+            projection="X6c/1c",
+            frame=["pa1d", "sa1d", "NWse"],
+        )
+    fig.basemap(frame=["pa1d", "sa1d", "nwSE"])
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_map_grid_cross_size():
+    """
+    Test that setting `MAP_GRID_CROSS_SIZE` config changes both
+    `MAP_GRID_CROSS_SIZE_PRIMARY` and `MAP_GRID_CROSS_SIZE_SECONDARY`.
+    """
+    fig = Figure()
+    config(
+        MAP_GRID_CROSS_SIZE_PRIMARY="0p", MAP_GRID_CROSS_SIZE_SECONDARY="0p"
+    )  # Remove after https://github.com/GenericMappingTools/gmt/issues/3062 is fixed
+    with config(MAP_GRID_CROSS_SIZE="3p"):
+        fig.basemap(
+            region=["2020-1-24T21:00", "2020-1-25T00:00", 0, 1],
+            projection="X6c/2c",
+            frame=["pa1Hg", "sa45mg45m", "NWse"],
+        )
+    fig.basemap(frame=["pa1Hg", "sa45mg45m", "nwSE"], Y=-3)
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_map_grid_pen():
+    """
+    Test that setting `MAP_GRID_PEN` config changes both
+    `MAP_GRID_PEN_PRIMARY` and `MAP_GRID_PEN_SECONDARY`.
+    """
+    fig = Figure()
+    with config(MAP_GRID_PEN="thick,red"):
+        fig.basemap(
+            region=["2020-1-24T21:00", "2020-1-25T00:00", 0, 1],
+            projection="X6c/2c",
+            frame=["pa1Hg", "sa45mg45m", "NWse"],
+        )
+    fig.basemap(frame=["pa1Hg", "sa45mg45m", "nwSE"], Y=-3)
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_map_tick_length():
+    """
+    Test that setting `MAP_TICK_LENGTH` config changes both
+    `MAP_TICK_LENGTH_PRIMARY` and `MAP_TICK_LENGTH_SECONDARY`.
+    """
+    fig = Figure()
+    with config(MAP_TICK_LENGTH="5p"):
+        fig.basemap(
+            region=["2020-1-24T21:00", "2020-1-25T00:00", 0, 1],
+            projection="X6c/2c",
+            frame=["pa1Hg", "sa45mg45m", "NWse"],
+        )
+    fig.basemap(frame=["pa1Hg", "sa45mg45m", "nwSE"], Y=-3)
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_config_map_tick_pen():
+    """
+    Test that setting `MAP_TICK_PEN` config changes both
+    `MAP_TICK_PEN_PRIMARY` and `MAP_TICK_PEN_SECONDARY`.
+    """
+    fig = Figure()
+    with config(MAP_TICK_PEN="thick,red"):
+        fig.basemap(
+            region=["2020-1-24T21:00", "2020-1-25T00:00", 0, 1],
+            projection="X6c/2c",
+            frame=["pa1Hg", "sa45mg45m", "NWse"],
+        )
+    fig.basemap(frame=["pa1Hg", "sa45mg45m", "nwSE"], Y=-3)
+    return fig