regulators: Add pmbus_write_vout_command action

Implement the pmbus_write_vout_command action in the JSON config file.
See pmbus_write_vout_command.md for more information about this action.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: Idef8da56d19df8a416efec068ffa9fb9493100cc
diff --git a/phosphor-regulators/test/actions/pmbus_write_vout_command_action_tests.cpp b/phosphor-regulators/test/actions/pmbus_write_vout_command_action_tests.cpp
new file mode 100644
index 0000000..f2a5d9a
--- /dev/null
+++ b/phosphor-regulators/test/actions/pmbus_write_vout_command_action_tests.cpp
@@ -0,0 +1,631 @@
+/**
+ * Copyright © 2020 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "action_environment.hpp"
+#include "action_error.hpp"
+#include "device.hpp"
+#include "i2c_interface.hpp"
+#include "id_map.hpp"
+#include "mocked_i2c_interface.hpp"
+#include "pmbus_error.hpp"
+#include "pmbus_utils.hpp"
+#include "pmbus_write_vout_command_action.hpp"
+#include "write_verification_error.hpp"
+
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <stdexcept>
+#include <string>
+#include <utility>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+using namespace phosphor::power::regulators;
+
+using ::testing::A;
+using ::testing::Return;
+using ::testing::SetArgReferee;
+using ::testing::Throw;
+using ::testing::TypedEq;
+
+TEST(PMBusWriteVoutCommandActionTests, Constructor)
+{
+    // Test where works: Volts value and exponent value are specified
+    try
+    {
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{true};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.getVolts().has_value(), true);
+        EXPECT_EQ(action.getVolts().value(), 1.3);
+        EXPECT_EQ(action.getFormat(), pmbus_utils::VoutDataFormat::linear);
+        EXPECT_EQ(action.getExponent().has_value(), true);
+        EXPECT_EQ(action.getExponent().value(), -8);
+        EXPECT_EQ(action.isVerified(), true);
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where works: Volts value and exponent value are not specified
+    try
+    {
+        std::optional<double> volts{};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.getVolts().has_value(), false);
+        EXPECT_EQ(action.getFormat(), pmbus_utils::VoutDataFormat::linear);
+        EXPECT_EQ(action.getExponent().has_value(), false);
+        EXPECT_EQ(action.isVerified(), false);
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: Data format is not linear
+    try
+    {
+        std::optional<double> volts{};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::direct};
+        std::optional<int8_t> exponent{};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const std::invalid_argument& e)
+    {
+        EXPECT_STREQ(e.what(), "Unsupported data format specified");
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+}
+
+TEST(PMBusWriteVoutCommandActionTests, Execute)
+{
+    // Test where works: Volts value and exponent value defined in action;
+    // write is verified.
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will not read from VOUT_MODE (command/register 0x20)
+        // * will write 0x014D to VOUT_COMMAND (command/register 0x21)
+        // * will read 0x014D from VOUT_COMMAND
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(A<uint8_t>(), A<uint8_t&>())).Times(0);
+        EXPECT_CALL(*i2cInterface,
+                    write(TypedEq<uint8_t>(0x21), TypedEq<uint16_t>(0x014D)))
+            .Times(1);
+        EXPECT_CALL(*i2cInterface, read(TypedEq<uint8_t>(0x21), A<uint16_t&>()))
+            .Times(1)
+            .WillOnce(SetArgReferee<1>(0x014D));
+
+        // Create Device, IDMap, and ActionEnvironment
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        // Linear format volts value = (1.3 / 2^(-8)) = 332.8 = 333 = 0x014D
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{true};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.execute(env), true);
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where works: Volts value defined in ActionEnvironment; exponent
+    // value defined in VOUT_MODE; write is not verified.
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will read 0b0001'0111 (linear format, -9 exponent) from VOUT_MODE
+        // * will write 0x069A to VOUT_COMMAND
+        // * will not read from VOUT_COMMAND
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(TypedEq<uint8_t>(0x20), A<uint8_t&>()))
+            .Times(1)
+            .WillOnce(SetArgReferee<1>(0b0001'0111));
+        EXPECT_CALL(*i2cInterface,
+                    write(TypedEq<uint8_t>(0x21), TypedEq<uint16_t>(0x069A)))
+            .Times(1);
+        EXPECT_CALL(*i2cInterface, read(A<uint8_t>(), A<uint16_t&>())).Times(0);
+
+        // Create Device, IDMap, and ActionEnvironment.  Set volts value to 3.3
+        // in ActionEnvironment.
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+        env.setVolts(3.3);
+
+        // Create and execute action
+        // Linear format volts value = (3.3 / 2^(-9)) = 1689.6 = 1690 = 0x069A
+        std::optional<double> volts{};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.execute(env), true);
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: No volts value defined
+    try
+    {
+        // Create IDMap and ActionEnvironment
+        IDMap idMap{};
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        std::optional<double> volts{};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const ActionError& e)
+    {
+        EXPECT_STREQ(
+            e.what(),
+            "ActionError: pmbus_write_vout_command: { format: linear, "
+            "exponent: -8, is_verified: false }: No volts value defined");
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: Unable to get I2C interface to current device
+    try
+    {
+        // Create IDMap and ActionEnvironment
+        IDMap idMap{};
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const std::invalid_argument& e)
+    {
+        EXPECT_STREQ(e.what(), "Unable to find device with ID \"reg1\"");
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: Unable to read VOUT_MODE to get exponent
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will try to read VOUT_MODE; exception will be thrown
+        // * will not write to VOUT_COMMAND due to exception
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(TypedEq<uint8_t>(0x20), A<uint8_t&>()))
+            .Times(1)
+            .WillOnce(Throw(
+                i2c::I2CException{"Failed to read byte", "/dev/i2c-1", 0x70}));
+        EXPECT_CALL(*i2cInterface, write(A<uint8_t>(), A<uint16_t>())).Times(0);
+
+        // Create Device, IDMap, and ActionEnvironment
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        std::optional<double> volts{3.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const ActionError& e)
+    {
+        EXPECT_STREQ(e.what(),
+                     "ActionError: pmbus_write_vout_command: { volts: 3.3, "
+                     "format: linear, is_verified: false }");
+        try
+        {
+            // Re-throw inner I2CException
+            std::rethrow_if_nested(e);
+            ADD_FAILURE() << "Should not have reached this line.";
+        }
+        catch (const i2c::I2CException& ie)
+        {
+            EXPECT_STREQ(
+                ie.what(),
+                "I2CException: Failed to read byte: bus /dev/i2c-1, addr 0x70");
+        }
+        catch (...)
+        {
+            ADD_FAILURE() << "Should not have caught exception.";
+        }
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: VOUT_MODE data format is not linear
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will read 0b0010'0000 (vid data format) from VOUT_MODE
+        // * will not write to VOUT_COMMAND due to data format error
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(TypedEq<uint8_t>(0x20), A<uint8_t&>()))
+            .Times(1)
+            .WillOnce(SetArgReferee<1>(0b0010'0000));
+        EXPECT_CALL(*i2cInterface, write(A<uint8_t>(), A<uint16_t>())).Times(0);
+
+        // Create Device, IDMap, and ActionEnvironment
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        std::optional<double> volts{3.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const ActionError& e)
+    {
+        EXPECT_STREQ(e.what(),
+                     "ActionError: pmbus_write_vout_command: { volts: 3.3, "
+                     "format: linear, is_verified: false }");
+        try
+        {
+            // Re-throw inner PMBusError
+            std::rethrow_if_nested(e);
+            ADD_FAILURE() << "Should not have reached this line.";
+        }
+        catch (const PMBusError& pe)
+        {
+            EXPECT_STREQ(
+                pe.what(),
+                "PMBusError: VOUT_MODE contains unsupported data format");
+        }
+        catch (...)
+        {
+            ADD_FAILURE() << "Should not have caught exception.";
+        }
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: Unable to write VOUT_COMMAND
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will not read from VOUT_MODE
+        // * will try to write 0x014D to VOUT_COMMAND; exception will be thrown
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(A<uint8_t>(), A<uint8_t&>())).Times(0);
+        EXPECT_CALL(*i2cInterface,
+                    write(TypedEq<uint8_t>(0x21), TypedEq<uint16_t>(0x014D)))
+            .Times(1)
+            .WillOnce(Throw(i2c::I2CException{"Failed to write word data",
+                                              "/dev/i2c-1", 0x70}));
+
+        // Create Device, IDMap, and ActionEnvironment
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        // Linear format volts value = (1.3 / 2^(-8)) = 332.8 = 333 = 0x014D
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const ActionError& e)
+    {
+        EXPECT_STREQ(e.what(),
+                     "ActionError: pmbus_write_vout_command: { volts: 1.3, "
+                     "format: linear, exponent: -8, is_verified: false }");
+        try
+        {
+            // Re-throw inner I2CException
+            std::rethrow_if_nested(e);
+            ADD_FAILURE() << "Should not have reached this line.";
+        }
+        catch (const i2c::I2CException& ie)
+        {
+            EXPECT_STREQ(ie.what(), "I2CException: Failed to write word data: "
+                                    "bus /dev/i2c-1, addr 0x70");
+        }
+        catch (...)
+        {
+            ADD_FAILURE() << "Should not have caught exception.";
+        }
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: Unable to read VOUT_COMMAND
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will not read from VOUT_MODE
+        // * will write 0x014D to VOUT_COMMAND
+        // * will try to read from VOUT_COMMAND; exception will be thrown
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(A<uint8_t>(), A<uint8_t&>())).Times(0);
+        EXPECT_CALL(*i2cInterface,
+                    write(TypedEq<uint8_t>(0x21), TypedEq<uint16_t>(0x014D)))
+            .Times(1);
+        EXPECT_CALL(*i2cInterface, read(TypedEq<uint8_t>(0x21), A<uint16_t&>()))
+            .Times(1)
+            .WillOnce(Throw(i2c::I2CException{"Failed to read word data",
+                                              "/dev/i2c-1", 0x70}));
+
+        // Create Device, IDMap, and ActionEnvironment
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        // Linear format volts value = (1.3 / 2^(-8)) = 332.8 = 333 = 0x014D
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{true};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const ActionError& e)
+    {
+        EXPECT_STREQ(e.what(),
+                     "ActionError: pmbus_write_vout_command: { volts: 1.3, "
+                     "format: linear, exponent: -8, is_verified: true }");
+        try
+        {
+            // Re-throw inner I2CException
+            std::rethrow_if_nested(e);
+            ADD_FAILURE() << "Should not have reached this line.";
+        }
+        catch (const i2c::I2CException& ie)
+        {
+            EXPECT_STREQ(ie.what(), "I2CException: Failed to read word data: "
+                                    "bus /dev/i2c-1, addr 0x70");
+        }
+        catch (...)
+        {
+            ADD_FAILURE() << "Should not have caught exception.";
+        }
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where fails: Write verification error
+    try
+    {
+        // Create mock I2CInterface.  Expect action to do the following:
+        // * will not read from VOUT_MODE
+        // * will write 0x014D to VOUT_COMMAND
+        // * will read 0x014C from VOUT_COMMAND (not equal to 0x014D)
+        std::unique_ptr<i2c::MockedI2CInterface> i2cInterface =
+            std::make_unique<i2c::MockedI2CInterface>();
+        EXPECT_CALL(*i2cInterface, isOpen).Times(1).WillOnce(Return(true));
+        EXPECT_CALL(*i2cInterface, read(A<uint8_t>(), A<uint8_t&>())).Times(0);
+        EXPECT_CALL(*i2cInterface,
+                    write(TypedEq<uint8_t>(0x21), TypedEq<uint16_t>(0x014D)))
+            .Times(1);
+        EXPECT_CALL(*i2cInterface, read(TypedEq<uint8_t>(0x21), A<uint16_t&>()))
+            .Times(1)
+            .WillOnce(SetArgReferee<1>(0x014C));
+
+        // Create Device, IDMap, and ActionEnvironment
+        Device device{"reg1", true, "/system/chassis/motherboard/reg1",
+                      std::move(i2cInterface)};
+        IDMap idMap{};
+        idMap.addDevice(device);
+        ActionEnvironment env{idMap, "reg1"};
+
+        // Create and execute action
+        // Linear format volts value = (1.3 / 2^(-8)) = 332.8 = 333 = 0x014D
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{true};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        action.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const ActionError& e)
+    {
+        EXPECT_STREQ(e.what(),
+                     "ActionError: pmbus_write_vout_command: { volts: 1.3, "
+                     "format: linear, exponent: -8, is_verified: true }");
+        try
+        {
+            // Re-throw inner WriteVerificationError
+            std::rethrow_if_nested(e);
+            ADD_FAILURE() << "Should not have reached this line.";
+        }
+        catch (const WriteVerificationError& we)
+        {
+            EXPECT_STREQ(
+                we.what(),
+                "WriteVerificationError: device: reg1, register: VOUT_COMMAND, "
+                "value_written: 0x14D, value_read: 0x14C");
+        }
+        catch (...)
+        {
+            ADD_FAILURE() << "Should not have caught exception.";
+        }
+    }
+    catch (...)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+}
+
+TEST(PMBusWriteVoutCommandActionTests, GetExponent)
+{
+    std::optional<double> volts{1.3};
+    pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+    bool isVerified{true};
+
+    // Exponent value was specified
+    {
+        std::optional<int8_t> exponent{-9};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.getExponent().has_value(), true);
+        EXPECT_EQ(action.getExponent().value(), -9);
+    }
+
+    // Exponent value was not specified
+    {
+        std::optional<int8_t> exponent{};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.getExponent().has_value(), false);
+    }
+}
+
+TEST(PMBusWriteVoutCommandActionTests, GetFormat)
+{
+    std::optional<double> volts{};
+    pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+    std::optional<int8_t> exponent{};
+    bool isVerified{false};
+    PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+    EXPECT_EQ(action.getFormat(), pmbus_utils::VoutDataFormat::linear);
+}
+
+TEST(PMBusWriteVoutCommandActionTests, GetVolts)
+{
+    pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+    std::optional<int8_t> exponent{-8};
+    bool isVerified{true};
+
+    // Volts value was specified
+    {
+        std::optional<double> volts{1.3};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.getVolts().has_value(), true);
+        EXPECT_EQ(action.getVolts().value(), 1.3);
+    }
+
+    // Volts value was not specified
+    {
+        std::optional<double> volts{};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.getVolts().has_value(), false);
+    }
+}
+
+TEST(PMBusWriteVoutCommandActionTests, IsVerified)
+{
+    std::optional<double> volts{1.3};
+    pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+    std::optional<int8_t> exponent{-8};
+    bool isVerified{true};
+    PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+    EXPECT_EQ(action.isVerified(), true);
+}
+
+TEST(PMBusWriteVoutCommandActionTests, ToString)
+{
+    // Test where volts value and exponent value are specified
+    {
+        std::optional<double> volts{1.3};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{-8};
+        bool isVerified{true};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(action.toString(),
+                  "pmbus_write_vout_command: { volts: 1.3, format: linear, "
+                  "exponent: -8, is_verified: true }");
+    }
+
+    // Test where volts value and exponent value are not specified
+    {
+        std::optional<double> volts{};
+        pmbus_utils::VoutDataFormat format{pmbus_utils::VoutDataFormat::linear};
+        std::optional<int8_t> exponent{};
+        bool isVerified{false};
+        PMBusWriteVoutCommandAction action{volts, format, exponent, isVerified};
+        EXPECT_EQ(
+            action.toString(),
+            "pmbus_write_vout_command: { format: linear, is_verified: false }");
+    }
+}