tests: aravissrc gst element switch test

This test crashes as soon as the new source element is put in PLAYING mode. But
that is probably due to a mishandling of the pipeline. Doing this sort of
pipeline manipulation seems not trivial:
<https://gstreamer.freedesktop.org/documentation/application-development/advanced/pipeline-manipulation.html?gi-language=c>

meson.build

@@ -99,7 +99,6 @@ else # not Linux
 endif
 
 subdir ('src')
-subdir ('tests')
 
 viewer_enabled = false
 viewer_option = get_option ('viewer')
@@ -116,6 +115,8 @@ gst_deps = aravis_dependencies + [dependency ('gstreamer-base-1.0', required: gs
                                   dependency ('gstreamer-app-1.0', required: gst_option)]
 subdir('gst', if_found: gst_deps)
 
+subdir ('tests')
+
 doc_deps = dependency ('gi-docgen', version:'>= 2021.1', fallback: ['gi-docgen', 'dummy_dep'], required:get_option('documentation'))
 subdir('docs', if_found: doc_deps)
 

tests/arvgsttest.c

@@ -0,0 +1,100 @@
+/* Simple script which will start an aravis pipeline, then restart ONLY the camera. */
+#include <gst/gst.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int
+main (int argc, char *argv[])
+{
+        GstElement *pipeline;
+        GstElement *source;
+        GstElement *sink;
+        GstElement *new_source;
+        GstState current_state, pending_state;
+
+        gst_init (&argc, &argv);
+
+        pipeline = gst_pipeline_new ("aravis_pipeline");
+        source = gst_element_factory_make ("aravissrc", "source");
+        if (!source) {
+                printf ("Failed to create the source element\n");
+                return EXIT_FAILURE;
+        }
+
+        g_object_set(G_OBJECT(source),
+                     "camera-name", "Aravis-Fake-GV01",
+                     "num-arv-buffers", 5,
+                     "packet-resend", FALSE,
+                     "packet-size", 9000,
+                     "auto-packet-size", FALSE,
+                     NULL);
+
+        sink = gst_element_factory_make ("fakesink", "fake_sink");
+
+        if (!pipeline || !source || !sink) {
+                printf ("Not all elements could be created.\n");
+                return EXIT_FAILURE;
+        }
+
+        gst_bin_add_many (GST_BIN (pipeline), source, sink, NULL);
+
+        if (!gst_element_link (source, sink)) {
+                printf ("Elements could not be linked.\n");
+                gst_object_unref (pipeline);
+                return EXIT_FAILURE;
+        }
+
+        printf ("Start the pipeline\n");
+        g_assert_cmpint (gst_element_set_state(pipeline, GST_STATE_PLAYING), ==, GST_STATE_CHANGE_ASYNC);
+
+        printf ("Wait for a few frames\n");
+        sleep (1);
+
+        printf ("Stop the source\n");
+        g_assert_cmpint (gst_element_set_state(source, GST_STATE_NULL), ==, GST_STATE_CHANGE_SUCCESS);
+
+        gst_element_get_state (source, &current_state, &pending_state, 0);
+        printf ("source current state:%d - pending state:%d\n", current_state, pending_state);
+
+        sleep (1);
+
+        gst_element_unlink(source, sink);
+        g_assert (gst_bin_remove(GST_BIN(pipeline), source));
+
+        printf ("Create a new source\n");
+        new_source = gst_element_factory_make ("aravissrc", "new_source");
+        if (!new_source) {
+                printf ("Failed to create the source element\n");
+                return EXIT_FAILURE;
+        }
+        g_object_set(G_OBJECT(new_source),
+                     "camera-name", "Aravis-Fake-GV01",
+                     "num-arv-buffers", 5,
+                     "packet-resend", FALSE,
+                     "packet-size", 9000,
+                     "auto-packet-size", FALSE,
+                     NULL);
+
+        g_assert (gst_bin_add(GST_BIN(pipeline), new_source));
+        g_assert (gst_element_link(new_source, sink));
+        g_assert (gst_element_sync_state_with_parent(new_source));
+
+        gst_element_get_state (source, &current_state, &pending_state, 0);
+        printf ("new source current state:%d - pending state:%d\n", current_state, pending_state);
+
+        printf ("Start the new source\n");
+        g_assert_cmpint (gst_element_set_state(source, GST_STATE_PLAYING), ==, GST_STATE_CHANGE_SUCCESS);
+
+        gst_element_get_state (source, &current_state, &pending_state, 0);
+        printf ("new source current state:%d - pending state:%d\n", current_state, pending_state);
+
+        printf ("Wait for a few frames\n");
+
+        printf ("Stop the pipeline\n");
+        g_assert_cmpint (gst_element_set_state (pipeline, GST_STATE_NULL), ==, GST_STATE_CHANGE_SUCCESS);
+
+        printf ("Free the pipeline\n");
+        gst_object_unref (pipeline);
+
+        return EXIT_SUCCESS;
+}

tests/meson.build

@@ -101,4 +101,12 @@ if get_option('tests')
 						  include_directories: [library_inc])
 	endforeach
 
+        if gst_enabled
+          executable ('arv-gst-test', 'arvgsttest.c',
+          link_with: aravis_library,
+          dependencies: aravis_dependencies + gst_deps,
+          include_directories: [library_inc])
+
+        endif
+
 endif