Add image value checking to testing script

ci/test_mapserver_image.sh

@@ -190,9 +190,32 @@ curl_layer_times() {
 curl_empty_tile() {
     debug "Starting curl basic mapfile request..."
     # NOTE: The time doesn't actually exist and no image data is available. A blank image should be returned
-    curl --fail -sS "http://localhost:8888/wms/g16/abi/radf/l1b?VERSION=1.1.1&REQUEST=GetMap&SERVICE=WMS&STYLES=&BBOX=-1330667.479176%2c-2773559.926648%2c2773559.926648%2c1330667.479176&WIDTH=256&HEIGHT=256&FORMAT=rgba&SRS=EPSG%3a930916&LAYERS=C01&TIME=2022-04-20T16:00:21Z" >/dev/null || pg_exit_status=1
+    curl --fail -sS -o "empty_tile.png" "http://localhost:8888/wms/g16/abi/radf/l1b?VERSION=1.1.1&REQUEST=GetMap&SERVICE=WMS&STYLES=&BBOX=-1330667.479176%2c-2773559.926648%2c2773559.926648%2c1330667.479176&WIDTH=256&HEIGHT=256&FORMAT=rgba&SRS=EPSG%3a930916&LAYERS=C01&TIME=2022-04-20T16:00:21Z" >/dev/null || pg_exit_status=1
+    check_image_content "empty_tile.png" 0
 }
 
+check_image_content() {
+    img_filename=$1
+    pixel_value=$2
+    docker exec -i test pip install pillow >/dev/null
+    incontainer_file="/tmp/$(basename $img_filename)"
+    docker cp $img_filename test:${incontainer_file}
+    docker exec -i test python3 <<EOF
+import sys
+import io
+import os
+
+import numpy as np
+from PIL import Image
+
+img = Image.open("${incontainer_file}")
+img_arr = np.asarray(img)
+assert img_arr.shape == (256, 256, 4)
+assert (img_arr[:, :, :3] == ${pixel_value}).all()
+EOF
+}
+
+
 run_basic_shapefile_tests() {
     setup_test
     debug "Starting shapefile tests..."
@@ -215,6 +238,8 @@ run_basic_postgres_tests() {
     add_postgres_projections
     add_postgres_tables
     add_postgres_content
+    # TODO: Verify empty tile is empty
+    # TODO: Add fake geotiff and tile check for inserted time and verify non-empty result
 
     curl_index
     curl_layer_times "[\"${C01_ISOTIME}\"]"