r.centroids: Fix module and test (#815)

* Fixes wrong variable names in the r.centroids code.
* Fixes test for r.centroids.
* Fixes also r.sample.category test by defining an appropriate computational region. (Unrelated)

src/raster/r.centroids/r.centroids.py

@@ -42,8 +42,8 @@ def main():
     options, flags = gs.parser()
 
     # options and flags into variables
-    ipl = options["input"]
-    opl = options["output"]
+    in_raster = options["input"]
+    out_vector = options["output"]
     gs.run_command(
         "r.volume",
         quiet=True,

src/raster/r.centroids/testsuite/test_r_centroids.py

@@ -31,14 +31,13 @@ def setUpClass(cls):
         # to not override mapset's region (which might be used by other tests)
         cls.use_temp_region()
         # cls.runModule or self.runModule is used for general module calls
-        cls.runModule("g.region", raster="basins")
+        cls.runModule("g.region", raster="basin")
 
     @classmethod
     def tearDownClass(cls):
         """Remove temporary region"""
         cls.del_temp_region()
 
-    @classmethod
     def tearDown(self):
         """
         Remove the outputs created from the centroids module
@@ -51,7 +50,7 @@ def test_output(self):
         # assertModule is used to call module which we test
         # we expect module to finish successfully
         self.assertModule(
-            "r.centroids", input="basins", output=self.centroids, overwrite=True
+            "r.centroids", input="basin", output=self.centroids, overwrite=True
         )
 
         self.assertVectorEqualsAscii(

src/raster/r.sample.category/testsuite/test_numbers.sh

@@ -3,6 +3,7 @@
 num_points_expected=42
 num_cats_expected=7
 
+g.region raster=landclass96
 r.sample.category input=landclass96 output=landclass_points npoints=6 --o
 
 num_points=$(v.db.select -c landclass_points | wc -l)