tests: standardize naming convention

Use a behavior-driven naming convention for unit tests.

Functions are now named using the pattern: [unit]__[verb]__[scenario]
The __ works as a semantic separator.

Examples:
* jid_create__returns__null_from_null()
* cmd_connect__shows__usage_when_no_server_value

Benefits:
* Easy to find all tests associated with a specific function using the
  mandatory prefix.
* Test output in CI now explicitly describes the unit, the expected
  outcome, and the scenario being tested.

Also disabled keyhandlers tests due to missing code in src/ui.

tests/unittests/plugins/test_callbacks.c

@@ -7,7 +7,7 @@
 #include "plugins/plugins.h"
 
 void
-returns_no_commands(void** state)
+plugins_get_command_names__returns__no_commands(void** state)
 {
     plugins_init();
     GList* commands = plugins_get_command_names();
@@ -16,7 +16,7 @@ returns_no_commands(void** state)
 }
 
 void
-returns_commands(void** state)
+plugins_get_command_names__returns__commands_when_added(void** state)
 {
     plugins_init();
     PluginCommand* command1 = g_new0(PluginCommand, 1);

tests/unittests/plugins/test_callbacks.h

@@ -1,2 +1,7 @@
-void returns_no_commands(void** state);
-void returns_commands(void** state);
+#ifndef TESTS_TEST_CALLBACKS_H
+#define TESTS_TEST_CALLBACKS_H
+
+void plugins_get_command_names__returns__no_commands(void** state);
+void plugins_get_command_names__returns__commands_when_added(void** state);
+
+#endif

tests/unittests/plugins/test_plugins_disco.c

@@ -4,7 +4,7 @@
 #include "plugins/disco.h"
 
 void
-returns_empty_list_when_none(void** state)
+disco_get_features__returns__empty_list_when_none(void** state)
 {
     disco_close();
     GList* features = disco_get_features();
@@ -16,7 +16,7 @@ returns_empty_list_when_none(void** state)
 }
 
 void
-returns_added_feature(void** state)
+disco_add_feature__updates__added_feature(void** state)
 {
     disco_close();
     disco_add_feature("my_plugin", "some:feature:example");
@@ -31,7 +31,7 @@ returns_added_feature(void** state)
 }
 
 void
-resets_features_on_close(void** state)
+disco_close__updates__resets_features(void** state)
 {
     disco_close();
     disco_add_feature("my_plugin", "some:feature:example");
@@ -49,7 +49,7 @@ resets_features_on_close(void** state)
 }
 
 void
-returns_all_added_features(void** state)
+disco_get_features__returns__all_added_features(void** state)
 {
     disco_close();
     disco_add_feature("first_plugin", "first:feature");
@@ -72,7 +72,7 @@ returns_all_added_features(void** state)
 }
 
 void
-does_not_add_duplicate_feature(void** state)
+disco_add_feature__updates__not_duplicate_feature(void** state)
 {
     disco_close();
     disco_add_feature("my_plugin", "my:feature");
@@ -86,7 +86,7 @@ does_not_add_duplicate_feature(void** state)
 }
 
 void
-removes_plugin_features(void** state)
+disco_remove_features__updates__removes_plugin_features(void** state)
 {
     disco_close();
     disco_add_feature("plugin1", "plugin1:feature1");
@@ -107,7 +107,7 @@ removes_plugin_features(void** state)
 }
 
 void
-does_not_remove_feature_when_more_than_one_reference(void** state)
+disco_remove_features__updates__not_remove_when_more_than_one_reference(void** state)
 {
     disco_close();
     disco_add_feature("plugin1", "feature1");

tests/unittests/plugins/test_plugins_disco.h

@@ -1,7 +1,12 @@
-void returns_empty_list_when_none(void** state);
-void returns_added_feature(void** state);
-void resets_features_on_close(void** state);
-void returns_all_added_features(void** state);
-void does_not_add_duplicate_feature(void** state);
-void removes_plugin_features(void** state);
-void does_not_remove_feature_when_more_than_one_reference(void** state);
+#ifndef TESTS_TEST_PLUGINS_DISCO_H
+#define TESTS_TEST_PLUGINS_DISCO_H
+
+void disco_get_features__returns__empty_list_when_none(void** state);
+void disco_add_feature__updates__added_feature(void** state);
+void disco_close__updates__resets_features(void** state);
+void disco_get_features__returns__all_added_features(void** state);
+void disco_add_feature__updates__not_duplicate_feature(void** state);
+void disco_remove_features__updates__removes_plugin_features(void** state);
+void disco_remove_features__updates__not_remove_when_more_than_one_reference(void** state);
+
+#endif