unit: add invalid channels/freqs to test-band

Tests some channels and frequencies that are not in E-4 and
would pass the conversion without validation.

unit/test-band.c

@@ -650,6 +650,26 @@ static void test_6ghz_freqs(const void *data)
 	}
 }
 
+static void test_conversions(const void *data)
+{
+	/*
+	 * Test a few invalid channels/frequencies that appear valid but are
+	 * not in the E-4 table. The checks in band.c seem to cover 2.4Ghz and
+	 * 6Ghz very well since there are no gaps, but the 5GHz band has some
+	 * segmentation.
+	 */
+
+	/* Gap in 5GHz channels between 68 and 96 */
+	assert(!band_channel_to_freq(72, BAND_FREQ_5_GHZ));
+	assert(!band_freq_to_channel(5360, NULL));
+
+	/* Invalid channel using 4000mhz starting frequency */
+	assert(!band_channel_to_freq(183, BAND_FREQ_5_GHZ));
+	assert(!band_freq_to_channel(4915, NULL));
+
+	assert(!band_channel_to_freq(192, BAND_FREQ_5_GHZ));
+}
+
 int main(int argc, char *argv[])
 {
 	l_test_init(&argc, &argv);
@@ -715,5 +735,7 @@ int main(int argc, char *argv[])
 	l_test_add("/band/6ghz/channels", test_6ghz_channels, NULL);
 	l_test_add("/band/6ghz/freq", test_6ghz_freqs, NULL);
 
+	l_test_add("/band/conversions", test_conversions, NULL);
+
 	return l_test_run();
 }