tests: build: Avoid linking against sip module

Fixes the deprecation warning from meson:

DEPRECATION: target sip links against shared module sip, which is incorrect.
             This will be an error in the future, so please use shared_library() for sip instead.
             If shared_module() was used for sip because it has references to undefined symbols,
             use shared_libary() with `override_options: ['b_lundef=false']` instead.

plugins/sip/calls-sip-provider.c

@@ -83,6 +83,16 @@ struct _CallsSipProvider
 static void calls_sip_provider_message_source_interface_init (CallsMessageSourceInterface *iface);
 static void calls_sip_provider_account_provider_interface_init (CallsAccountProviderInterface *iface);
 
+#ifdef FOR_TESTING
+
+G_DEFINE_TYPE_WITH_CODE
+(CallsSipProvider, calls_sip_provider, CALLS_TYPE_PROVIDER,
+ G_IMPLEMENT_INTERFACE (CALLS_TYPE_MESSAGE_SOURCE,
+                        calls_sip_provider_message_source_interface_init)
+ G_IMPLEMENT_INTERFACE (CALLS_TYPE_ACCOUNT_PROVIDER,
+                        calls_sip_provider_account_provider_interface_init))
+
+#else
 
 G_DEFINE_DYNAMIC_TYPE_EXTENDED
 (CallsSipProvider, calls_sip_provider, CALLS_TYPE_PROVIDER, 0,
@@ -91,6 +101,8 @@ G_DEFINE_DYNAMIC_TYPE_EXTENDED
  G_IMPLEMENT_INTERFACE_DYNAMIC (CALLS_TYPE_ACCOUNT_PROVIDER,
                                 calls_sip_provider_account_provider_interface_init))
 
+#endif /* FOR_TESTING */
+
 typedef struct {
   CallsSipProvider *provider;
   GKeyFile         *key_file;
@@ -502,11 +514,14 @@ calls_sip_provider_dispose (GObject *object)
 }
 
 
+#ifndef FOR_TESTING
+
 static void
 calls_sip_provider_class_finalize (CallsSipProviderClass *klass)
 {
 }
 
+#endif /* FOR_TESTING */
 
 static void
 calls_sip_provider_class_init (CallsSipProviderClass *klass)
@@ -813,6 +828,7 @@ calls_sip_provider_save_accounts_to_disk (CallsSipProvider *self)
 }
 
 
+#ifndef FOR_TESTING
 
 G_MODULE_EXPORT void
 peas_register_types (PeasObjectModule *module)
@@ -823,3 +839,5 @@ peas_register_types (PeasObjectModule *module)
                                               CALLS_TYPE_PROVIDER,
                                               CALLS_TYPE_SIP_PROVIDER);
 }
+
+#endif /* FOR_TESTING */