[rygel] test: Add tests for MetaConfig

[Jens Georg <jensgeorg src gnome org>]

commit 373abd66fe6a146d74ff400e8be46902bba366f1
Author: Jens Georg <mail jensge org>
Date:   Wed Apr 22 13:56:27 2020 +0200

    test: Add tests for MetaConfig

 src/librygel-core/rygel-meta-config.vala | 16 ++++++
 tests/meson.build                        | 12 ++++
 tests/rygel-meta-config-test.vala        | 99 ++++++++++++++++++++++++++++++++
 3 files changed, 127 insertions(+)
---
diff --git a/src/librygel-core/rygel-meta-config.vala b/src/librygel-core/rygel-meta-config.vala
index 313f3b40..cd5a36c6 100644
--- a/src/librygel-core/rygel-meta-config.vala
+++ b/src/librygel-core/rygel-meta-config.vala
@@ -62,6 +62,12 @@ public class Rygel.MetaConfig : GLib.Object, Configuration {
         return meta_config;
     }
 
+    /**
+     * Register another configuration provider to the meta configuration
+     * First configuration to provide a value wins. If you want to assign
+     * priority to configuration providers, they have to be added with descending
+     * priority
+     */
     public static void register_configuration (Configuration config) {
         if (MetaConfig.configs == null) {
             MetaConfig.configs = new ArrayList<Configuration> ();
@@ -73,6 +79,16 @@ public class Rygel.MetaConfig : GLib.Object, Configuration {
         }
     }
 
+    /**
+     * Convenoience method for cleaning up the singleton. This
+     * Should usually not be used; only if you care for your
+     * valgrind report or in tests
+     */
+    public static void cleanup () {
+        MetaConfig.meta_config = null;
+        MetaConfig.configs = null;
+    }
+
     public string get_interface () throws GLib.Error {
         string val = null;
         bool unavailable = true;
diff --git a/tests/meson.build b/tests/meson.build
index bb690457..45579018 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -79,6 +79,18 @@ test('rygel-plugin-loader-test',
     workdir : meson.current_source_dir(),
 )
 
+test('rygel-meta-config-test',
+    executable(
+        'rygel-meta-config-test',
+        files(
+            'rygel-meta-config-test.vala'
+        ),
+        dependencies : [
+            rygel_core
+        ]
+    )
+)
+
 test('rygel-searchable-container-test', searchable_container_test)
 test('rygel-object-creator-test', object_creator_test)
 test('rygel-regression-test', regression_test)
diff --git a/tests/rygel-meta-config-test.vala b/tests/rygel-meta-config-test.vala
new file mode 100644
index 00000000..147748bc
--- /dev/null
+++ b/tests/rygel-meta-config-test.vala
@@ -0,0 +1,99 @@
+class TestConfig : Rygel.BaseConfiguration {
+    public HashTable<string, bool> enable = new HashTable<string, bool> (str_hash, str_equal);
+
+    public void toggl_enable (string module) {
+        print("%s ->", enable[module].to_string ());
+        enable[module] = !enable[module];
+        print("%s\n", enable[module].to_string ());
+        this.section_changed (module, Rygel.SectionEntry.ENABLED);
+    }
+
+    public override bool get_enabled(string module) throws Error {
+        if (module in this.enable) {
+            return this.enable[module];
+        }
+
+        throw new Rygel.ConfigurationError.NO_VALUE_SET ("Should not happen");
+    }
+}
+
+void
+test_meta_config_single_instance ()
+{
+    Test.summary ("Test whether we actually get only one instance");
+    var instance_a = Rygel.MetaConfig.get_default ();
+    var instance_b = Rygel.MetaConfig.get_default ();
+
+    assert (instance_a == instance_b);
+    Rygel.MetaConfig.cleanup ();
+}
+
+const string SECTION_A = "Tracker";
+const string SECTION_B = "SomePlugin";
+
+void
+test_meta_config_overrides () {
+
+    var first_config = new TestConfig ();
+    first_config.enable[SECTION_A] = true;
+
+    Rygel.MetaConfig.register_configuration (first_config);
+
+    var second_config = new TestConfig ();
+    second_config.enable[SECTION_A] = false;
+    second_config.enable[SECTION_B] = true;
+
+    Rygel.MetaConfig.register_configuration (second_config);
+
+    var instance = Rygel.MetaConfig.get_default ();
+
+    // Check that signalling a change for a value that only exists
+    // on lower priority will trigger a signal on the MetaConfig
+    assert_true (instance.get_enabled (SECTION_A));
+    assert_true (instance.get_enabled (SECTION_B));
+
+    var id = instance.section_changed.connect ((section, entry) => {
+        assert_true (section == SECTION_B);
+        assert_true (entry == Rygel.SectionEntry.ENABLED);
+        assert_false (instance.get_enabled (section));
+    });
+
+    second_config.toggl_enable (SECTION_B);
+    instance.disconnect (id);
+
+    // Check that changing a value on a lower priority will not
+    // propagated up if there is a value with higher priority
+    id = instance.section_changed.connect ((section, entry) => {
+        assert_not_reached ();
+    });
+    second_config.toggl_enable (SECTION_A);
+    instance.disconnect (id);
+
+    // Check that changing a value on a higher priority will be
+    // propagated up
+    id = instance.section_changed.connect ((section, entry) => {
+        assert_true (section == SECTION_A);
+        assert_true (entry == Rygel.SectionEntry.ENABLED);
+        try {
+            assert_false (instance.get_enabled (section));
+        } catch (Error error) {
+            assert_not_reached ();
+        }
+    });
+    first_config.toggl_enable (SECTION_A);
+    instance.disconnect (id);
+
+    Rygel.MetaConfig.cleanup ();
+}
+
+int main(string[] args) {
+    Test.init (ref args);
+
+    Test.add_func ("/librygel-core/meta-config/single-instance",
+                   test_meta_config_single_instance);
+
+    Test.add_func ("/librygel-core/meta-config/overrides",
+                   test_meta_config_overrides);
+
+    return Test.run ();
+}