r.mblend: basic tests (#911)

* Adds first test suit: basic module functioning and simple control parameter effect
* Corrects small issue in the module with temporary map name

src/raster/r.mblend/testsuite/test_rmblend.py

@@ -0,0 +1,86 @@
+from grass.gunittest.case import TestCase
+from grass.gunittest.main import test
+
+
+class TestRMblend(TestCase):
+    """Simple tests for the r.mblend add-on. Makes sure it works and produces
+    reasonable results.
+    """
+
+    low_res = "low_res"
+    high_res_1 = "high_res_1"
+    high_res_2 = "high_res_2"
+    result_1 = "result_1"
+    result_2 = "result_2"
+
+    @classmethod
+    def setUpClass(cls):
+
+        cls.runModule("g.region", s=0, n=100, w=0, e=100, res=2)
+        cls.runModule("r.mapcalc", expression="{} = 2".format(cls.low_res))
+        cls.runModule("g.region", s=0, n=100, w=0, e=60, res=1)
+        cls.runModule("r.mapcalc", expression="{} = 1".format(cls.high_res_1))
+        cls.runModule("g.region", s=20, n=80, w=30, e=70, res=1)
+        cls.runModule("r.mapcalc", expression="{} = 1".format(cls.high_res_2))
+        cls.runModule("g.region", s=0, n=100, w=0, e=100, res=1)
+
+    @classmethod
+    def tearDownClass(cls):
+
+        cls.runModule(
+            "g.remove",
+            type="raster",
+            flags="f",
+            name=[cls.high_res_1, cls.high_res_2, cls.low_res],
+        )
+
+    def tearDown(self):
+
+        self.runModule(
+            "g.remove",
+            type="raster",
+            flags="f",
+            name=[self.result_1, self.result_2],
+        )
+
+    def test_module_basic(self):
+
+        self.assertModule(
+            "r.mblend",
+            high=self.high_res_1,
+            low=self.low_res,
+            output=self.result_1,
+        )
+        self.assertRasterExists(name=self.result_1)
+
+    def test_results(self):
+
+        self.assertModule(
+            "r.mblend",
+            high=self.high_res_1,
+            low=self.low_res,
+            output=self.result_1,
+            inter_points=100,
+        )
+        self.assertRasterExists(name=self.result_1)
+        values = {"min": 1, "max": 2, "mean": 1.187, "stddev": 0.316}
+        self.assertRasterFitsUnivar(
+            raster=self.result_1, reference=values, precision=1e-3
+        )
+
+        self.assertModule(
+            "r.mblend",
+            high=self.high_res_2,
+            low=self.low_res,
+            output=self.result_2,
+            far_edge=50,
+        )
+        self.assertRasterExists(name=self.result_2)
+        values = {"min": 1, "max": 2, "mean": 1.448, "stddev": 0.417}
+        self.assertRasterFitsUnivar(
+            raster=self.result_2, reference=values, precision=1e-3
+        )
+
+
+if __name__ == "__main__":
+    test()