[v2,2/2] hw/i386/postcard: New test suite for the ISA POST card device

diff --git a/MAINTAINERS b/MAINTAINERS
index 33b13583b7..801494d955 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1723,6 +1723,7 @@  ISA POST card
 M: Lev Kujawski <lkujaw@member.fsf.org>
 S: Supported
 F: hw/i386/postcard.c
+F: tests/qtest/postcard-test.c
 
 Xtensa Machines
 ---------------
diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build
index 31287a9173..0718bdb394 100644
--- a/tests/qtest/meson.build
+++ b/tests/qtest/meson.build
@@ -47,6 +47,7 @@  qtests_i386 = \
   (config_all_devices.has_key('CONFIG_ISA_IPMI_KCS') ? ['ipmi-kcs-test'] : []) +            \
   (config_host.has_key('CONFIG_LINUX') and                                                  \
    config_all_devices.has_key('CONFIG_ISA_IPMI_BT') ? ['ipmi-bt-test'] : []) +              \
+  (config_all_devices.has_key('CONFIG_POST_CARD') ? ['postcard-test'] : []) +               \
   (config_all_devices.has_key('CONFIG_WDT_IB700') ? ['wdt_ib700-test'] : []) +              \
   (config_all_devices.has_key('CONFIG_PVPANIC_ISA') ? ['pvpanic-test'] : []) +              \
   (config_all_devices.has_key('CONFIG_PVPANIC_PCI') ? ['pvpanic-pci-test'] : []) +          \
diff --git a/tests/qtest/postcard-test.c b/tests/qtest/postcard-test.c
new file mode 100644
index 0000000000..2e04876d4a
--- /dev/null
+++ b/tests/qtest/postcard-test.c
@@ -0,0 +1,122 @@ 
+/*
+ * Test Suite for the ISA POST Card
+ *
+ * Copyright (c) 2022 Lev Kujawski
+ *
+ *  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 2 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest-single.h"
+#include "hw/i386/postcard.h"
+
+
+/* I/O helper functions */
+static void
+post_card_write(uint8_t val)
+{
+    outb(POST_CARD_PORT_DEFAULT, val);
+}
+
+static uint8_t
+post_card_readb(void)
+{
+    return inb(POST_CARD_PORT_DEFAULT);
+}
+
+static uint16_t
+post_card_readw(void)
+{
+    return inw(POST_CARD_PORT_DEFAULT);
+}
+
+static uint32_t
+post_card_readl(void)
+{
+    return inl(POST_CARD_PORT_DEFAULT);
+}
+
+
+/* Testing framework */
+static QTestState *qts;
+
+static void
+test_setup(void)
+{
+    assert(qts == NULL);
+    qts = qtest_start("-machine pc");
+    assert(qts != NULL);
+}
+
+static void
+test_teardown(void)
+{
+    assert(qts != NULL);
+    qtest_quit(qts);
+    qts = NULL;
+}
+
+
+/* Test cases */
+static void
+test_initial_state(void)
+{
+    test_setup();
+    g_assert_cmphex(post_card_readb(), ==, 0x00);
+    test_teardown();
+}
+
+static void
+test_retain_write(void)
+{
+    test_setup();
+    g_assert_cmphex(post_card_readb(), ==, 0x00);
+    post_card_write(0xaa);
+    g_assert_cmphex(post_card_readb(), ==, 0xaa);
+    test_teardown();
+}
+
+static void
+test_read_word(void)
+{
+    test_setup();
+    g_assert_cmphex(post_card_readb(), ==, 0x00);
+    post_card_write(0xa5);
+    g_assert_cmphex(post_card_readw(), ==, 0xa5a5);
+    test_teardown();
+}
+
+static void
+test_read_double_word(void)
+{
+    test_setup();
+    g_assert_cmphex(post_card_readb(), ==, 0x00);
+    post_card_write(0xa5);
+    g_assert_cmphex(post_card_readl(), ==, 0xa5a5a5a5);
+    test_teardown();
+}
+
+
+int
+main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    qtest_add_func("/postcard/initial_state", test_initial_state);
+    qtest_add_func("/postcard/retain_write", test_retain_write);
+    qtest_add_func("/postcard/read_word", test_read_word);
+    qtest_add_func("/postcard/read_double_word", test_read_double_word);
+
+    return g_test_run();
+}