Fix failing grdinfo tests

In GMT 6.1, `grdinfo` also reports registration code at the end of the output.

See GenericMappingTools/gmt#3359 for upstream changes.

Author: seisman

pygmt/clib/session.py

@@ -111,7 +111,7 @@ class Session:
     ...             )
     ...             # Read the contents of the temp file before it's deleted.
     ...             print(fout.read().strip())
-    -180 180 -90 90 -8592.14453125 5558.79248047 1 1 361 181
+    -180 180 -90 90 -8592.14453125 5558.79248047 1 1 361 181 0
     """
 
     # The minimum version of GMT required
@@ -1226,8 +1226,8 @@ def virtualfile_from_grid(self, grid):
         ...             args = '{} -L0 -Cn ->{}'.format(fin, fout.name)
         ...             ses.call_module('grdinfo', args)
         ...             print(fout.read().strip())
-        -180 180 -90 90 -8592.14453125 5558.79248047 1 1 361 181
-        >>> # The output is: w e s n z0 z1 dx dy n_columns n_rows
+        -180 180 -90 90 -8592.14453125 5558.79248047 1 1 361 181 0
+        >>> # The output is: w e s n z0 z1 dx dy n_columns n_rows registration
 
         """
         # Conversion to a C-contiguous array needs to be done here and not in

pygmt/tests/test_grdinfo.py

@@ -13,13 +13,13 @@ def test_grdinfo():
     "Make sure grd info works as expected"
     grid = load_earth_relief()
     result = grdinfo(grid, L=0, C="n")
-    assert result.strip() == "-180 180 -90 90 -8592.14453125 5558.79248047 1 1 361 181"
+    assert result.strip() == "-180 180 -90 90 -8592.14453125 5558.79248047 1 1 361 181 0"
 
 
 def test_grdinfo_file():
     "Test grdinfo with file input"
     result = grdinfo("@earth_relief_60m", L=0, C="n")
-    assert result.strip() == "-180 180 -90 90 -8592.14465255 5558.79248047 1 1 361 181"
+    assert result.strip() == "-180 180 -90 90 -8592.14465255 5558.79248047 1 1 361 181 0"
 
 
 def test_grdinfo_fails():