tests: Add tests for SessionLimits interface

This adds tests for the getter and setter for session limits, giving us
65.9% branch coverage (but that includes `g_return_if_fail()` and
friends, which are impossible and pointless to test both sides of the
branch).

Signed-off-by: Philip Withnall <withnall@endlessm.com>

libmalcontent/tests/meson.build

@@ -33,9 +33,14 @@ accounts_service_iface_c = custom_target(
             '@INPUT@'],
 )
 
+accounts_service_extension_ifaces = [
+  join_paths(meson.source_root(), 'accounts-service', 'com.endlessm.ParentalControls.AppFilter.xml'),
+  join_paths(meson.source_root(), 'accounts-service', 'com.endlessm.ParentalControls.SessionLimits.xml'),
+]
+
 accounts_service_extension_iface_h = custom_target(
   'accounts-service-extension-iface.h',
-  input: ['com.endlessm.ParentalControls.AppFilter.xml'],
+  input: accounts_service_extension_ifaces,
   output: ['accounts-service-extension-iface.h'],
   command: [gdbus_codegen,
             '--interface-info-header',
@@ -44,7 +49,7 @@ accounts_service_extension_iface_h = custom_target(
 )
 accounts_service_extension_iface_c = custom_target(
   'accounts-service-extension-iface.c',
-  input: ['com.endlessm.ParentalControls.AppFilter.xml'],
+  input: accounts_service_extension_ifaces,
   output: ['accounts-service-extension-iface.c'],
   command: [gdbus_codegen,
             '--interface-info-body',
@@ -59,6 +64,12 @@ test_programs = [
     accounts_service_extension_iface_h,
     accounts_service_extension_iface_c,
   ], deps],
+  ['session-limits', [
+    accounts_service_iface_h,
+    accounts_service_iface_c,
+    accounts_service_extension_iface_h,
+    accounts_service_extension_iface_c,
+  ], deps],
 ]
 
 installed_tests_metadir = join_paths(datadir, 'installed-tests',