Add simple tests for testing voice selection by name.

Makefile.am

@@ -232,9 +232,16 @@ tests_tokenizer_test_SOURCES = \
 	src/libespeak-ng/tokenizer.c \
 	tests/tokenizer.c
 
-check:	tests/encoding.test tests/tokenizer.test tests/languages.test
+noinst_bin_PROGRAMS += tests/voices.test
+
+tests_voices_test_LDADD   = src/libespeak-ng.la
+tests_voices_test_CFLAGS  = -Isrc/libespeak-ng ${AM_CFLAGS}
+tests_voices_test_SOURCES = tests/voices.c
+
+check:	tests/encoding.test tests/tokenizer.test tests/voices.test tests/languages.test
 	tests/encoding.test
 	tests/tokenizer.test
+	ESPEAK_DATA_PATH=$(PWD) tests/voices.test
 	tests/languages.test
 
 ##### phoneme data:

tests/voices.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2017 Reece H. Dunn
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write see:
+ *             <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <espeak-ng/espeak_ng.h>
+#include <espeak-ng/speak_lib.h>
+
+void
+test_selection_by_name()
+{
+	printf("testing selection of voice by name\n");
+
+	assert(espeak_SetVoiceByName("de") == EE_OK);
+
+	assert(espeak_SetVoiceByName("und") == EE_NOT_FOUND);
+
+	assert(espeak_ng_SetVoiceByName("de") == ENS_OK);
+
+	assert(espeak_ng_SetVoiceByName("und") == ENS_VOICE_NOT_FOUND);
+}
+
+int
+main(int argc, char **argv)
+{
+	assert(espeak_Initialize(AUDIO_OUTPUT_SYNCHRONOUS, 0, NULL, espeakINITIALIZE_DONT_EXIT) == 22050);
+
+	test_selection_by_name();
+
+	assert(espeak_Terminate() == EE_OK);
+
+	printf("done\n");
+
+	return EXIT_SUCCESS;
+}