r.surf.volcano: add test script

Yeah, I know, but I don't enjoy working with Python.

src/raster/r.surf.volcano/testsuite/test_rvolc.sh

@@ -0,0 +1,69 @@
+#!/bin/sh
+#  Test case for r.surf.volcano: check that resulting raster map
+#    is within some arbitrary threshold of matching the map I get.
+#    Exits with 0 if everything passed, 1 if something failed.
+#  Hamish Bowman Sept. 2024
+#
+# See gunittest_testing.html's basic example for a pretty relevant
+# set of tests. See also r.surf.random's tests for inspiration.
+
+# Tested within the NC sample dataset (nc_spm_08).
+g.region n=5120 s=0 w=0 e=5120 res=10
+
+# touches r.mapcalc, g.region, r.info, g.rename, g.remove
+r.surf.volcano method=gaussian output="volcano.gauss.$$"
+
+if [ $? -ne 0 ] ; then
+   echo "ERROR r.surf.volcano test: did not exit cleanly" 1>&2
+   exit 1
+fi
+
+eval `r.univar -g "volcano.gauss.$$"`
+g.remove -f rast name="volcano.gauss.$$"
+
+
+# reference values
+ref_max=1000
+ref_mean=31.3
+ref_stddev=121.1
+
+# completely arbitrary cross platform variance threshold
+var=5
+
+
+result=`echo "$max $ref_max $var" | awk \
+  'function abs(x){return ((x < 0) ? -x : x)}
+   {if( abs($1 - $2) < $3 ) {print "ok"}
+   else {print "bad"} }'`
+
+if [ "$result" = "bad" ] ; then
+   echo "ERROR r.surf.volcano test: out of bounds raster maximum" 1>&2
+   exit 1
+fi
+
+
+result=`echo "$mean $ref_mean $var" | awk \
+  'function abs(x){return ((x < 0) ? -x : x)}
+   {if( abs($1 - $2) < $3 ) {print "ok"}
+   else {print "bad"} }'`
+
+if [ "$result" = "bad" ] ; then
+   echo "ERROR r.surf.volcano test: out of bounds raster mean" 1>&2
+   exit 1
+fi
+
+
+result=`echo "$stddev $ref_stddev $var" | awk \
+  'function abs(x){return ((x < 0) ? -x : x)}
+   {if( abs($1 - $2) < $3 ) {print "ok"}
+   else {print "bad"} }'`
+
+if [ "$result" = "bad" ] ; then
+   echo "ERROR r.surf.volcano test: out of bounds raster std.dev." 1>&2
+   exit 1
+fi
+
+
+# all good
+exit 0
+