Refactor xfail tests to avoid storing baseline images (#603)

This PR refactors the xfail/fail tests to let the tests pass and avoid storing baseline images.

The baseline images are generated by calling the same modules using plain text or 
grid files as input, and using single-character arguments.

* Refactor basemap tests
* Refactor legend tests
* Refactor coast tests
* Refactor colorbar tests
* Refactor makecpt tests
* Refactor logo tests
* Refactor grdcontour tests
* Refactor plot tests

Co-authored-by: Wei Ji <[email protected]>

Author: seisman

pygmt/tests/test_basemap.py

@@ -4,6 +4,7 @@
 import pytest
 
 from .. import Figure
+from ..helpers.testing import check_figures_equal
 from ..exceptions import GMTInvalidInput
 
 
@@ -54,15 +55,15 @@ def test_basemap_power_axis():
     return fig
 
 
-@pytest.mark.xfail(
-    reason="Baseline image not updated to use earth relief grid in GMT 6.1.0",
-)
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_basemap_polar():
     "Create a polar basemap plot"
-    fig = Figure()
-    fig.basemap(R="0/360/0/1000", J="P6i", B="afg")
-    return fig
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    fig_ref.basemap(R="0/360/0/1000", J="P6i", B="afg")
+    fig_test.basemap(region=[0, 360, 0, 1000], projection="P6i", frame="afg")
+
+    return fig_ref, fig_test
 
 
 @pytest.mark.mpl_image_compare

pygmt/tests/test_coast.py

@@ -4,6 +4,7 @@
 import pytest
 
 from .. import Figure
+from ..helpers.testing import check_figures_equal
 
 
 @pytest.mark.mpl_image_compare
@@ -25,15 +26,16 @@ def test_coast():
     return fig
 
 
-@pytest.mark.xfail(
-    reason="Baseline image not updated to use earth relief grid in GMT 6.1.0",
-)
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_coast_iceland():
     "Test passing in R as a list"
-    fig = Figure()
-    fig.coast(R=[-30, -10, 60, 65], J="m1c", B=True, G="p28+r100")
-    return fig
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    fig_ref.coast(R="-30/-10/60/65", J="m1c", B="", G="p28+r100")
+    fig_test.coast(
+        region=[-30, -10, 60, 65], projection="m1c", frame=True, land="p28+r100"
+    )
+    return fig_ref, fig_test
 
 
 @pytest.mark.mpl_image_compare

pygmt/tests/test_colorbar.py

@@ -4,6 +4,7 @@
 import pytest
 
 from .. import Figure
+from ..helpers.testing import check_figures_equal
 
 
 @pytest.mark.mpl_image_compare
@@ -37,18 +38,19 @@ def test_colorbar_positioned_using_map_coordinates():
     return fig
 
 
-@pytest.mark.xfail(
-    reason="Baseline image not updated to use earth relief grid in GMT 6.1.0",
-)
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_colorbar_positioned_using_justification_code():
     """
     Create colorbar at Top Center inside the map frame with length 2cm.
     """
-    fig = Figure()
-    fig.basemap(region=[2, 4, 6, 8], projection="t0/2c", frame=True)
-    fig.colorbar(cmap="rainbow", position="jTC+w2c")
-    return fig
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    fig_ref.basemap(R="2/4/6/8", J="t0/2c", B="")
+    fig_ref.colorbar(C="rainbow", D="jTC+w2c")
+
+    fig_test.basemap(region=[2, 4, 6, 8], projection="t0/2c", frame=True)
+    fig_test.colorbar(cmap="rainbow", position="jTC+w2c")
+    return fig_ref, fig_test
 
 
 @pytest.mark.mpl_image_compare

pygmt/tests/test_grdcontour.py

@@ -82,26 +82,36 @@ def test_grdcontour_file():
     return fig
 
 
-@pytest.mark.xfail(
-    reason="Baseline image not updated to use earth relief grid in GMT 6.1.0",
-)
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_grdcontour_interval_file_full_opts():
     """ Plot based on external contour level file """
-    fig = Figure()
-    comargs = {
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    comargs_ref = {
+        "grid": "@earth_relief_10m",
+        "R": "-161.5/-154/18.5/23",
+        "C": TEST_CONTOUR_FILE,
+        "S": 100,
+        "J": "M6i",
+        "Q": 10,
+    }
+    fig_ref.grdcontour(**comargs_ref, L="-25000/-1", W=["a1p,blue", "c0.5p,blue"])
+    fig_ref.grdcontour(**comargs_ref, L="0", W=["a1p,black", "c0.5p,black"])
+
+    comargs_test = {
         "region": [-161.5, -154, 18.5, 23],
         "interval": TEST_CONTOUR_FILE,
         "grid": "@earth_relief_10m",
         "resample": "100",
         "projection": "M6i",
         "cut": 10,
     }
+    fig_test.grdcontour(
+        **comargs_test, limit=(-25000, -1), pen=["a1p,blue", "c0.5p,blue"]
+    )
+    fig_test.grdcontour(**comargs_test, limit=0, pen=["a1p,black", "c0.5p,black"])
 
-    fig.grdcontour(**comargs, limit=(-25000, -1), pen=["a1p,blue", "c0.5p,blue"])
-
-    fig.grdcontour(**comargs, limit="0", pen=["a1p,black", "c0.5p,black"])
-    return fig
+    return fig_ref, fig_test
 
 
 def test_grdcontour_fails():

pygmt/tests/test_legend.py

@@ -6,6 +6,7 @@
 from .. import Figure
 from ..exceptions import GMTInvalidInput
 from ..helpers import GMTTempFile
+from ..helpers.testing import check_figures_equal
 
 
 @pytest.mark.mpl_image_compare
@@ -44,32 +45,42 @@ def test_legend_default_position():
     return fig
 
 
-@pytest.mark.xfail(
-    reason="Baseline image not updated to use earth relief grid in GMT 6.1.0",
-)
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_legend_entries():
     """
     Test different marker types/shapes.
     """
+    fig_ref, fig_test = Figure(), Figure()
 
-    fig = Figure()
-
-    fig.basemap(projection="x1i", region=[0, 7, 3, 7], frame=True)
+    # Use single-character arguments for the reference image
+    fig_ref = Figure()
+    fig_ref.basemap(J="x1i", R="0/7/3/7", B="")
+    fig_ref.plot(
+        data="@Table_5_11.txt",
+        S="c0.15i",
+        G="lightgreen",
+        W="faint",
+        l="Apples",
+    )
+    fig_ref.plot(data="@Table_5_11.txt", W="1.5p,gray", l='"My lines"')
+    fig_ref.plot(data="@Table_5_11.txt", S="t0.15i", G="orange", l="Oranges")
+    fig_ref.legend(D="JTR+jTR")
 
-    fig.plot(
+    fig_test.basemap(projection="x1i", region=[0, 7, 3, 7], frame=True)
+    fig_test.plot(
         data="@Table_5_11.txt",
         style="c0.15i",
         color="lightgreen",
         pen="faint",
-        l="Apples",
+        label="Apples",
     )
-    fig.plot(data="@Table_5_11.txt", pen="1.5p,gray", label='"My lines"')
-    fig.plot(data="@Table_5_11.txt", style="t0.15i", color="orange", label="Oranges")
-
-    fig.legend(position="JTR+jTR")
+    fig_test.plot(data="@Table_5_11.txt", pen="1.5p,gray", label='"My lines"')
+    fig_test.plot(
+        data="@Table_5_11.txt", style="t0.15i", color="orange", label="Oranges"
+    )
+    fig_test.legend(position="JTR+jTR")
 
-    return fig
+    return fig_ref, fig_test
 
 
 @pytest.mark.mpl_image_compare

pygmt/tests/test_logo.py

@@ -5,23 +5,32 @@
 
 from .. import Figure
 from ..exceptions import GMTInvalidInput
+from ..helpers.testing import check_figures_equal
 
 
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_logo():
     "Plot a GMT logo of a 2 inch width as a stand-alone plot"
-    fig = Figure()
-    fig.logo(D="x0/0+w2i")
-    return fig
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    fig_ref.logo(D="x0/0+w2i")
+    fig_test.logo(position="x0/0+w2i")
+    return fig_ref, fig_test
 
 
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_logo_on_a_map():
     "Plot a GMT logo in the upper right corner of a map"
-    fig = Figure()
-    fig.coast(region=[-90, -70, 0, 20], projection="M6i", land="chocolate", frame=True)
-    fig.logo(D="jTR+o0.1i/0.1i+w3i", F=True)
-    return fig
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    fig_ref.coast(R="-90/-70/0/20", J="M6i", G="chocolate", B="")
+    fig_ref.logo(D="jTR+o0.1i/0.1i+w3i", F="")
+
+    fig_test.coast(
+        region=[-90, -70, 0, 20], projection="M6i", land="chocolate", frame=True
+    )
+    fig_test.logo(position="jTR+o0.1i/0.1i+w3i", box=True)
+    return fig_ref, fig_test
 
 
 def test_logo_fails():

pygmt/tests/test_makecpt.py

@@ -10,6 +10,7 @@
 from ..datasets import load_earth_relief
 from ..exceptions import GMTInvalidInput
 from ..helpers import GMTTempFile
+from ..helpers.testing import check_figures_equal
 
 TEST_DATA_DIR = os.path.join(os.path.dirname(__file__), "data")
 POINTS_DATA = os.path.join(TEST_DATA_DIR, "points.txt")
@@ -62,19 +63,21 @@ def test_makecpt_to_plot_grid(grid):
     return fig
 
 
-@pytest.mark.xfail(
-    reason="Baseline image not updated to use earth relief grid in GMT 6.1.0",
-)
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_makecpt_to_plot_grid_scaled_with_series(grid):
     """
     Use static color palette table scaled to a min/max series to change color
     of grid
     """
-    fig = Figure()
+    # Use single-character arguments for the reference image
+    fig_ref = Figure()
+    makecpt(C="oleron", T="-4500/4500")
+    fig_ref.grdimage(grid, J="W0/6i")
+
+    fig_test = Figure()
     makecpt(cmap="oleron", series="-4500/4500")
-    fig.grdimage(grid, projection="W0/6i")
-    return fig
+    fig_test.grdimage(grid, projection="W0/6i")
+    return fig_ref, fig_test
 
 
 def test_makecpt_output_to_cpt_file():

pygmt/tests/test_plot.py

@@ -128,11 +128,21 @@ def test_plot_projection(data):
     return fig
 
 
-@pytest.mark.mpl_image_compare
+@check_figures_equal()
 def test_plot_colors(data, region):
     "Plot the data using z as colors"
-    fig = Figure()
-    fig.plot(
+    fig_ref, fig_test = Figure(), Figure()
+    # Use single-character arguments for the reference image
+    fig_ref.plot(
+        data=POINTS_DATA,
+        R="/".join(map(str, region)),
+        J="X3i",
+        S="c0.5c",
+        C="cubhelix",
+        B="af",
+    )
+
+    fig_test.plot(
         x=data[:, 0],
         y=data[:, 1],
         color=data[:, 2],
@@ -142,7 +152,7 @@ def test_plot_colors(data, region):
         cmap="cubhelix",
         frame="af",
     )
-    return fig
+    return fig_ref, fig_test
 
 
 @pytest.mark.mpl_image_compare