tests: add a teamcity output format for V's test runner (#16681)

cmd/tools/modules/testing/common.v

@@ -292,6 +292,9 @@ fn (mut ts TestSession) handle_test_runner_option() {
 		'dump' {
 			ts.reporter = DumpReporter{}
 		}
+		'teamcity' {
+			ts.reporter = TeamcityReporter{}
+		}
 		else {
 			dump('just set ts.reporter to an instance of your own struct here')
 		}

cmd/tools/modules/testing/output_teamcity.v

@@ -0,0 +1,57 @@
+module testing
+
+// TeamcityReporter implements the interface `testing.Reporter`.
+// It is used by `v -test-runner teamcity test .`
+pub struct TeamcityReporter {
+}
+
+pub fn (r TeamcityReporter) session_start(message string, mut ts TestSession) {
+}
+
+pub fn (r TeamcityReporter) session_stop(message string, mut ts TestSession) {
+}
+
+pub fn (r TeamcityReporter) report(index int, message LogMessage) {
+	name := r.get_test_suite_name_by_file(message.file)
+	match message.kind {
+		.cmd_begin {
+			eprintln("##teamcity[testSuiteStarted name='${name}' flowId='${message.flow_id}']")
+		}
+		.cmd_end {
+			eprintln("##teamcity[testSuiteFinished name='${name}' flowId='${message.flow_id}' duration='${message.took}']")
+		}
+		else {}
+	}
+}
+
+pub fn (r TeamcityReporter) get_test_suite_name_by_file(path string) string {
+	file_name := path.replace('\\', '/').split('/').last()
+	return file_name.split('.').first()
+}
+
+pub fn (r TeamcityReporter) report_stop() {
+}
+
+pub fn (r TeamcityReporter) progress(index int, message string) {
+}
+
+pub fn (r TeamcityReporter) update_last_line(index int, message string) {
+}
+
+pub fn (r TeamcityReporter) update_last_line_and_move_to_next(index int, message string) {
+}
+
+pub fn (r TeamcityReporter) message(index int, message string) {
+}
+
+pub fn (r TeamcityReporter) divider() {
+}
+
+pub fn (r TeamcityReporter) worker_threads_start(files []string, mut ts TestSession) {
+}
+
+pub fn (r TeamcityReporter) worker_threads_finish(mut ts TestSession) {
+}
+
+pub fn (r TeamcityReporter) list_of_failed_commands(failed_cmds []string) {
+}