zephyr: test: common charger code charger_enable_otg_power

Add some infrastructure for mocking out the charger driver functions to
simplify testing the remainder of `common/charger.c` and use it to test
charger_enable_otg_power()

BUG=None
BRANCH=None
TEST=./twister

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: I61b74c4cd2f8b7303b37c78cff0156db03c6191e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4000827
Reviewed-by: Jeremy Bettis <jbettis@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>

3 files changed, 100 insertions, 0 deletions

diff --git a/zephyr/test/drivers/common_charger/CMakeLists.txt b/zephyr/test/drivers/common_charger/CMakeLists.txt
index 58fc3229ef..63da1783f1 100644
--- a/zephyr/test/drivers/common_charger/CMakeLists.txt
+++ b/zephyr/test/drivers/common_charger/CMakeLists.txt
@@ -7,4 +7,5 @@ target_sources(app
   PRIVATE
     src/test_charge_state_v2.c
     src/test_common_charger.c
+    src/test_common_charger_mocked.c
 )
diff --git a/zephyr/test/drivers/common_charger/src/test_common_charger_mocked.c b/zephyr/test/drivers/common_charger/src/test_common_charger_mocked.c
new file mode 100644
index 0000000000..4c225dbffd
--- /dev/null
+++ b/zephyr/test/drivers/common_charger/src/test_common_charger_mocked.c
@@ -0,0 +1,98 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <string.h>
+#include <zephyr/fff.h>
+#include <zephyr/kernel.h>
+#include <zephyr/ztest.h>
+#include <zephyr/ztest_assert.h>
+
+#include "charger.h"
+#include "test/drivers/charger_utils.h"
+#include "test/drivers/test_state.h"
+
+/* This test suite only works if the chg_chips array is not const. */
+BUILD_ASSERT(IS_ENABLED(CONFIG_PLATFORM_EC_CHARGER_RUNTIME_CONFIG),
+	     "chg_chips array cannot be const.");
+
+/** Index of the charger chip we are overriding / working with. */
+#define CHG_NUM (0)
+
+/* FFF fakes for driver functions. These get assigned to members of the
+ * charger_drv struct
+ */
+FAKE_VALUE_FUNC(enum ec_error_list, enable_otg_power, int, int);
+
+struct common_charger_mocked_driver_fixture {
+	/* The original driver pointer that gets restored after the tests */
+	const struct charger_drv *saved_driver_ptr;
+	/* Mock driver that gets substituted */
+	struct charger_drv mock_driver;
+};
+
+ZTEST(common_charger_mocked_driver, test_charger_enable_otg_power__invalid)
+{
+	/* charger number out of bounds */
+	zassert_equal(EC_ERROR_INVAL, charger_enable_otg_power(-1, 0));
+	zassert_equal(EC_ERROR_INVAL, charger_enable_otg_power(INT_MAX, 0));
+}
+
+ZTEST(common_charger_mocked_driver, test_charger_enable_otg_power__unimpl)
+{
+	/* enable_otg_power is NULL */
+	zassert_equal(EC_ERROR_UNIMPLEMENTED,
+		      charger_enable_otg_power(CHG_NUM, 1));
+}
+
+ZTEST_F(common_charger_mocked_driver, test_charger_enable_otg_power)
+{
+	fixture->mock_driver.enable_otg_power = enable_otg_power;
+	enable_otg_power_fake.return_val = 123;
+
+	zassert_equal(enable_otg_power_fake.return_val,
+		      charger_enable_otg_power(CHG_NUM, 1));
+
+	zassert_equal(1, enable_otg_power_fake.call_count);
+	zassert_equal(CHG_NUM, enable_otg_power_fake.arg0_history[0]);
+	zassert_equal(1, enable_otg_power_fake.arg1_history[0]);
+}
+
+static void *setup(void)
+{
+	static struct common_charger_mocked_driver_fixture f;
+
+	zassert_true(board_get_charger_chip_count() > 0,
+		     "Need at least one charger chip present.");
+
+	/* Back up the current charger driver and substitute our own */
+	f.saved_driver_ptr = chg_chips[CHG_NUM].drv;
+	chg_chips[CHG_NUM].drv = &f.mock_driver;
+
+	return &f;
+}
+
+static void reset(void *data)
+{
+	struct common_charger_mocked_driver_fixture *f = data;
+
+	/* Reset the mock driver's function pointer table. Each tests adds these
+	 * as-needed
+	 */
+	f->mock_driver = (struct charger_drv){ 0 };
+
+	/* Reset fakes */
+	RESET_FAKE(enable_otg_power);
+}
+
+static void teardown(void *data)
+{
+	struct common_charger_mocked_driver_fixture *f = data;
+
+	/* Restore the original driver */
+	chg_chips[CHG_NUM].drv = f->saved_driver_ptr;
+}
+
+ZTEST_SUITE(common_charger_mocked_driver, drivers_predicate_post_main, setup,
+	    reset, reset, teardown);
diff --git a/zephyr/test/drivers/testcase.yaml b/zephyr/test/drivers/testcase.yaml
index a6c250c361..4eb41bc6e3 100644
--- a/zephyr/test/drivers/testcase.yaml
+++ b/zephyr/test/drivers/testcase.yaml
@@ -58,6 +58,7 @@ tests:
       # Set to focus testing for Herobrine
       # Config is y only in nissa
       - CONFIG_PLATFORM_EC_CHARGER_RAA489000=n
+      - CONFIG_PLATFORM_EC_CHARGER_RUNTIME_CONFIG=y
   drivers.chargesplash:
     timeout: 240
     extra_configs: