[processing] add test for merge gdal

Author: ghtmtt

python/plugins/processing/tests/testdata/custom/dem_to_merge1.tif

@@ -579,3 +579,39 @@ tests:
       OUTPUT:
         hash: f714597fadc9cfc3f5263dc0e35f7c6ba285de238dce439e4988faac
         type: rasterhash
+
+  - algorithm: gdal:merge
+    name: Merge 2 raster layers
+    params:
+      INPUT:
+        params:
+        - name: custom/dem_to_merge1.tif
+          type: raster
+        - name: custom/dem_to_merge2.tif
+          type: raster
+        type: multi
+      PCT: false
+      RTYPE: '5'
+      SEPARATE: false
+    results:
+      OUTPUT:
+        hash: fb6f0f4081308cc188eda2fbe106e04e0ebf866fc56853f0cca8db1c
+        type: rasterhash
+
+  - algorithm: gdal:merge
+    name: Merge layers and separate in bands
+    params:
+      INPUT:
+        params:
+        - name: custom/dem_to_merge1.tif
+          type: raster
+        - name: custom/dem_to_merge2.tif
+          type: raster
+        type: multi
+      PCT: false
+      RTYPE: '5'
+      SEPARATE: true
+    results:
+      OUTPUT:
+        hash: cbf7b8ca91e7d6cab5ef76eeed6ce80e5dbe173afb7b8eb4aed2e969
+        type: rasterhash