Run test_grdimage_over_dateline with debug mode on

Author: weiji14

pygmt/tests/test_grdimage.py

@@ -86,5 +86,5 @@ def test_grdimage_over_dateline(xrgrid):
     fig = Figure()
     assert xrgrid.gmt.registration == 0  # gridline registration
     xrgrid.gmt.gtype = 1  # geographic coordinate system
-    fig.grdimage(grid=xrgrid, region="g", projection="A0/0/1i")
+    fig.grdimage(grid=xrgrid, region="g", projection="A0/0/1i", V="d")
     return fig