feat(usb_host): Host tests for individual USB Host layers

- Public API CMock based Host tests
    - USB Host layer: driver install/uninstall unit test
    - USBH layer: driver install/uninstall unit test
    - Host tests are run in CI

components/usb/host_test/.build-test-rules.yml

@@ -0,0 +1,7 @@
+# Documentation: .gitlab/ci/README.md#manifest-file-to-control-the-buildtest-apps
+
+components/usb/host_test:
+  enable:
+    - if: IDF_TARGET == "linux"
+  depends_components:
+    - usb

components/usb/host_test/usb_host_layer_test/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+set(COMPONENTS main)
+
+list(APPEND EXTRA_COMPONENT_DIRS
+     "$ENV{IDF_PATH}/tools/mocks/usb/usb_host_layer_mock/usb"
+
+     # The following line would be needed to include the freertos mock component if this test used mocked FreeRTOS.
+     #"$ENV{IDF_PATH}/tools/mocks/freertos/"
+    )
+
+project(host_test_usb_host_layer)

components/usb/host_test/usb_host_layer_test/README.md

@@ -0,0 +1,37 @@
+| Supported Targets | Linux |
+| ----------------- | ----- |
+
+# Description
+
+This directory contains test code for `USB Host layer` of USB Host stack. Namely:
+* USB Host public API calls to install and uninstall the USB Host driver with partially mocked USB Host stack to test Linux build and Cmock run for this partial Mock
+* Mocked are all layers of the USB Host stack below the USB Host layer, which is used as a real component
+
+Tests are written using [Catch2](https://github.com/catchorg/Catch2) test framework, use CMock, so you must install Ruby on your machine to run them.
+
+This test directory uses freertos as real component
+
+# Build
+
+Tests build regularly like an idf project. Currently only working on Linux machines.
+
+```
+idf.py --preview set-target linux
+idf.py build
+```
+
+# Run
+
+The build produces an executable in the build folder.
+
+Just run:
+
+```
+idf.py monitor
+```
+
+or run the executable directly:
+
+```
+./build/host_test_usb_host_layer.elf
+```

components/usb/host_test/usb_host_layer_test/main/CMakeLists.txt

@@ -0,0 +1,12 @@
+set(srcs)
+list(APPEND srcs "test_main.cpp"
+                 "usb_host_install_unit_test.cpp"
+                 )
+
+idf_component_register(SRCS  ${srcs}
+                        REQUIRES cmock usb
+                        WHOLE_ARCHIVE)
+
+# The following line would be needed to provide the 'main' function if this test used mocked FreeRTOS.
+# As this test uses the real FreeRTOS implementation, we don't need Catch2 to provide 'main'.
+#target_link_libraries(${COMPONENT_LIB} PRIVATE Catch2WithMain)

components/usb/host_test/usb_host_layer_test/main/idf_component.yml

@@ -0,0 +1,2 @@
+dependencies:
+  espressif/catch2: "^3.4.0"

components/usb/host_test/usb_host_layer_test/main/test_main.cpp

@@ -0,0 +1,27 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <catch2/catch_session.hpp>
+#include <catch2/catch_test_macros.hpp>
+
+extern "C" void app_main(void)
+{
+    int argc = 1;
+    const char *argv[2] = {
+        "target_test_main",
+        NULL
+    };
+
+    auto result = Catch::Session().run(argc, argv);
+    if (result != 0) {
+        printf("Test failed with result %d\n", result);
+    } else {
+        printf("Test passed.\n");
+    }
+    fflush(stdout);
+    exit(result);
+}

components/usb/host_test/usb_host_layer_test/main/usb_host_install_unit_test.cpp

@@ -0,0 +1,254 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <catch2/catch_test_macros.hpp>
+
+#include "usb_host.h"   // Real implementation of usb_host.h
+
+// Test all the mocked headers defined for this mock
+extern "C" {
+#include "Mockusb_phy.h"
+#include "Mockhcd.h"
+#include "Mockusbh.h"
+#include "Mockenum.h"
+#include "Mockhub.h"
+}
+
+SCENARIO("USB Host pre-uninstall")
+{
+    // No USB Host driver previously installed
+    GIVEN("No USB Host previously installed") {
+
+        // Uninstall not-installed USB Host
+        SECTION("Uninstalling not installed USB Host") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_uninstall());
+        }
+    }
+}
+
+SCENARIO("USB Host install")
+{
+    // USB Host config is not valid, USB Host driver is not installed from previous test case
+    GIVEN("No USB Host config, USB Host driver not installed") {
+
+        // Try to install the USB Host driver with usb_host_config set to nullptr
+        SECTION("USB Host config is nullptr") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_ARG
+            REQUIRE(ESP_ERR_INVALID_ARG == usb_host_install(nullptr));
+        }
+    }
+
+    // USB Host config struct
+    usb_host_config_t usb_host_config = {
+        .skip_phy_setup = false,
+        .root_port_unpowered = false,
+        .intr_flags = 1,
+        .enum_filter_cb = nullptr,
+    };
+
+    // USB host config is valid, USB Host driver is not installed from previous test case
+    GIVEN("USB Host config, USB Host driver not installed") {
+
+        // Try to install the USB Host driver, with PHY install error
+        SECTION("Fail to install USB Host - PHY Install error") {
+
+            // Make the PHY install to fail
+            usb_new_phy_ExpectAnyArgsAndReturn(ESP_ERR_INVALID_STATE);
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+
+        // Try to install the USB Host driver, with HCD Install error, use internal PHY
+        SECTION("Fail to install USB Host - HCD Install error (internal PHY)") {
+
+            // Make the PHY install to pass
+            usb_phy_handle_t phy_handle;
+            usb_new_phy_ExpectAnyArgsAndReturn(ESP_OK);
+            usb_new_phy_ReturnThruPtr_handle_ret(&phy_handle);
+
+            // make the HCD port install to fail
+            hcd_install_ExpectAnyArgsAndReturn(ESP_ERR_INVALID_STATE);
+
+            // goto hcd_err: We must uninstall the PHY
+            usb_del_phy_ExpectAndReturn(phy_handle, ESP_OK);
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+
+        // Try to install the USB Host driver, with HCD Install error, use external PHY
+        SECTION("Fail to install USB Host - HCD Install error (external PHY)") {
+
+            // Skip the PHY Setup (external phy)
+            usb_host_config.skip_phy_setup = true;
+
+            // make the HCD port install to fail
+            hcd_install_ExpectAnyArgsAndReturn(ESP_ERR_INVALID_STATE);
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+
+        // Try to install the USB Host driver, with USBH Install error, use internal PHY
+        SECTION("Fail to install USB Host - USBH install error") {
+
+            // Make the PHY install to pass
+            usb_phy_handle_t phy_handle;
+            usb_new_phy_ExpectAnyArgsAndReturn(ESP_OK);
+            usb_new_phy_ReturnThruPtr_handle_ret(&phy_handle);
+
+            // make the HCD port install to pass
+            hcd_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the USBH install to fail
+            usbh_install_ExpectAnyArgsAndReturn(ESP_ERR_INVALID_STATE);
+
+            // goto usbh_err: We must uninstall HCD port and PHY
+            hcd_uninstall_ExpectAndReturn(ESP_OK);
+            usb_del_phy_ExpectAndReturn(phy_handle, ESP_OK);
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+
+        // Try to install the USB Host driver, with Enum driver Install error, use internal PHY
+        SECTION("Fail to install USB Host - Enum driver install error") {
+
+            // Make the PHY install to pass
+            usb_phy_handle_t phy_handle;
+            usb_new_phy_ExpectAnyArgsAndReturn(ESP_OK);
+            usb_new_phy_ReturnThruPtr_handle_ret(&phy_handle);
+
+            // make the HCD port install to pass
+            hcd_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the USBH install to pass
+            usbh_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the ENUM Driver to fail
+            enum_install_ExpectAnyArgsAndReturn(ESP_ERR_INVALID_STATE);
+
+            // goto enum_err: We must uninstall USBH, HCD port and PHY
+            usbh_uninstall_ExpectAndReturn(ESP_OK);
+            hcd_uninstall_ExpectAndReturn(ESP_OK);
+            usb_del_phy_ExpectAndReturn(phy_handle, ESP_OK);
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+
+        // Try to install the USB Host driver, with Hub driver Install error, use internal PHY
+        SECTION("Fail to install USB Host - Hub driver install error") {
+
+            // Make the PHY install to pass
+            usb_phy_handle_t phy_handle;
+            usb_new_phy_ExpectAnyArgsAndReturn(ESP_OK);
+            usb_new_phy_ReturnThruPtr_handle_ret(&phy_handle);
+
+            // make the HCD port install to pass
+            hcd_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the USBH install to pass
+            usbh_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the ENUM Driver to pass
+            enum_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the HUB Driver to fail
+            hub_install_ExpectAnyArgsAndReturn(ESP_ERR_INVALID_STATE);
+
+            // goto hub_err: We must uninstall Enum driver, USBH, HCD port and PHY
+            enum_uninstall_ExpectAndReturn(ESP_OK);
+            usbh_uninstall_ExpectAndReturn(ESP_OK);
+            hcd_uninstall_ExpectAndReturn(ESP_OK);
+            usb_del_phy_ExpectAndReturn(phy_handle, ESP_OK);
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+
+        // Successfully install the USB Host driver
+        SECTION("Successfully install the USB Host driver") {
+
+            // Make the PHY install to pass
+            usb_phy_handle_t phy_handle;
+            usb_new_phy_ExpectAnyArgsAndReturn(ESP_OK);
+            usb_new_phy_ReturnThruPtr_handle_ret(&phy_handle);
+
+            // make the HCD port install to pass
+            hcd_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the USBH install to pass
+            usbh_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the ENUM Driver to pass
+            enum_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make the HUB Driver to pass
+            hub_install_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Make hub_root_start() to pass
+            hub_root_start_ExpectAndReturn(ESP_OK);
+
+            // Call the DUT function, expect ESP_OK
+            REQUIRE(ESP_OK == usb_host_install(&usb_host_config));
+        }
+    }
+
+    // USB Host config is valid, USB Host driver was successfully installed in previous test case
+    GIVEN("USB Host config, USB Host driver previously installed") {
+
+        // Try to install USB Host driver again, after it has been successfully installed
+        SECTION("Fail to install already installed USB Host driver") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_install(&usb_host_config));
+        }
+    }
+
+}
+
+SCENARIO("USB Host post-uninstall")
+{
+    // USB Host driver successfully installed from previous test case
+    GIVEN("USB Host previously installed") {
+
+        // Uninstall successfully installed USB Host driver
+        SECTION("Successfully uninstall the USB Host driver") {
+
+            // Make the hub_root_stop() to pass
+            hub_root_stop_ExpectAndReturn(ESP_OK);
+
+            // Make uninstalling of all the drivers to pass
+            hub_uninstall_ExpectAndReturn(ESP_OK);
+            enum_uninstall_ExpectAndReturn(ESP_OK);
+            usbh_uninstall_ExpectAndReturn(ESP_OK);
+            hcd_uninstall_ExpectAndReturn(ESP_OK);
+
+            // Make the usb_del_phy() to pass
+            usb_del_phy_ExpectAnyArgsAndReturn(ESP_OK);
+
+            // Call the DUT function, expect ESP_OK
+            REQUIRE(ESP_OK == usb_host_uninstall());
+        }
+    }
+
+    // USB Host driver successfully uninstalled from previous test case
+    GIVEN("USB Host successfully uninstalled") {
+
+        // USB Host successfully uninstalled, try to uninstall it again
+        SECTION("Uninstall already uninstalled USB Host driver") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usb_host_uninstall());
+        }
+    }
+}

components/usb/host_test/usb_host_layer_test/pytest_usb_host_layer_linux.py

@@ -0,0 +1,11 @@
+# SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Unlicense OR CC0-1.0
+import pytest
+from pytest_embedded import Dut
+from pytest_embedded_idf.utils import idf_parametrize
+
+
+@pytest.mark.host_test
+@idf_parametrize('target', ['linux'], indirect=['target'])
+def test_usb_host_host_layer_linux(dut: Dut) -> None:
+    dut.expect_exact('All tests passed', timeout=5)

components/usb/host_test/usb_host_layer_test/sdkconfig.defaults

@@ -0,0 +1,4 @@
+
+CONFIG_IDF_TARGET="linux"
+CONFIG_COMPILER_CXX_EXCEPTIONS=y
+CONFIG_UNITY_ENABLE_IDF_TEST_RUNNER=n

components/usb/host_test/usbh_layer_test/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+set(COMPONENTS main)
+
+list(APPEND EXTRA_COMPONENT_DIRS
+     "$ENV{IDF_PATH}/tools/mocks/usb/usbh_layer_mock/usb"
+
+     # The following line would be needed to include the freertos mock component if this test used mocked FreeRTOS.
+     #"$ENV{IDF_PATH}/tools/mocks/freertos/"
+    )
+
+project(host_test_usbh_layer)

components/usb/host_test/usbh_layer_test/README.md

@@ -0,0 +1,37 @@
+| Supported Targets | Linux |
+| ----------------- | ----- |
+
+# Description
+
+This directory contains test code for `USBH layer` of USB Host stack. Namely:
+* USBH public API calls to install and uninstall the USBH driver with partially mocked USB Host stack to test Linux build and Cmock run for this partial Mock
+* Mocked are all layers of the USB Host stack below the USBH layer, which is used as a real component
+
+Tests are written using [Catch2](https://github.com/catchorg/Catch2) test framework, use CMock, so you must install Ruby on your machine to run them.
+
+This test directory uses freertos as a real component
+
+# Build
+
+Tests build regularly like an idf project. Currently only working on Linux machines. 
+
+```
+idf.py --preview set-target linux
+idf.py build
+```
+
+# Run
+
+The build produces an executable in the build folder.
+
+Just run:
+
+```
+idf.py monitor
+```
+
+or run the executable directly:
+
+```
+./build/host_test_usbh_layer.elf
+```

components/usb/host_test/usbh_layer_test/main/CMakeLists.txt

@@ -0,0 +1,12 @@
+set(srcs)
+list(APPEND srcs "test_main.cpp"
+                 "usbh_install_unit_test.cpp"
+                 )
+
+idf_component_register(SRCS  ${srcs}
+                        REQUIRES cmock usb
+                        WHOLE_ARCHIVE)
+
+# The following line would be needed to provide the 'main' function if this test used mocked FreeRTOS.
+# As this test uses the real FreeRTOS implementation, we don't need Catch2 to provide 'main'.
+#target_link_libraries(${COMPONENT_LIB} PRIVATE Catch2WithMain)

components/usb/host_test/usbh_layer_test/main/idf_component.yml

@@ -0,0 +1,2 @@
+dependencies:
+  espressif/catch2: "^3.4.0"

components/usb/host_test/usbh_layer_test/main/test_main.cpp

@@ -0,0 +1,27 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <catch2/catch_session.hpp>
+#include <catch2/catch_test_macros.hpp>
+
+extern "C" void app_main(void)
+{
+    int argc = 1;
+    const char *argv[2] = {
+        "target_test_main",
+        NULL
+    };
+
+    auto result = Catch::Session().run(argc, argv);
+    if (result != 0) {
+        printf("Test failed with result %d\n", result);
+    } else {
+        printf("Test passed.\n");
+    }
+    fflush(stdout);
+    exit(result);
+}

components/usb/host_test/usbh_layer_test/main/usbh_install_unit_test.cpp

@@ -0,0 +1,94 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <catch2/catch_test_macros.hpp>
+
+#include "usbh.h"   // Real implementation of usbh.h
+
+// Test all the mocked headers defined for this mock
+extern "C" {
+#include "Mockhcd.h"
+#include "Mockusb_private.h"
+}
+
+SCENARIO("USBH pre-uninstall")
+{
+    // No USBH driver previously installed
+    GIVEN("No USBH previously installed") {
+
+        // Uninstall not-installed USBH driver
+        SECTION("Uninstalling not installed USBH driver") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usbh_uninstall());
+        }
+    }
+}
+
+SCENARIO("USBH install")
+{
+    // USBH config is not valid, USBH driver is not previously installed
+    GIVEN("No USBH config, USBH driver not installed") {
+
+        // Try to install the USBH driver with usbh_config set to nullptr
+        SECTION("USBH config is nullptr") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_ARG
+            REQUIRE(ESP_ERR_INVALID_ARG == usbh_install(nullptr));
+        }
+    }
+
+    // USBH config struct
+    usbh_config_t usbh_config = {};
+
+    // USBH config is valid, USBH driver is not previously installed
+    GIVEN("USBH config, USBH driver not installed") {
+
+        // Successfully install the USBH Driver
+        SECTION("Successfully install the USBH Driver") {
+
+            // Call the DUT function, expect ESP_OK
+            REQUIRE(ESP_OK == usbh_install(&usbh_config));
+        }
+    }
+
+    // USBH config is valid, USBH driver is previously installed
+    GIVEN("USBH config, USBH driver previously installed") {
+
+        SECTION("Fail to install already installed USBH driver") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usbh_install(&usbh_config));
+        }
+    }
+}
+
+SCENARIO("USBH post-uninstall")
+{
+
+    // USBH driver successfully installed from previous test case
+    GIVEN("USBH driver previously installed") {
+
+        // Uninstall successfully installed USBH driver
+        SECTION("Successfully uninstall the USBH driver") {
+
+            // Call the DUT function, expect ESP_OK
+            REQUIRE(ESP_OK == usbh_uninstall());
+        }
+    }
+
+    // USBH driver successfully uninstalled from previous test case
+    GIVEN("USBH successfully uninstalled") {
+
+        // USBH successfully uninstalled, try to uninstall it again
+        SECTION("Uninstall already uninstalled USBH driver") {
+
+            // Call the DUT function, expect ESP_ERR_INVALID_STATE
+            REQUIRE(ESP_ERR_INVALID_STATE == usbh_uninstall());
+        }
+    }
+}

components/usb/host_test/usbh_layer_test/pytest_usbh_layer_linux.py

@@ -0,0 +1,11 @@
+# SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Unlicense OR CC0-1.0
+import pytest
+from pytest_embedded import Dut
+from pytest_embedded_idf.utils import idf_parametrize
+
+
+@pytest.mark.host_test
+@idf_parametrize('target', ['linux'], indirect=['target'])
+def test_usbh_layer_linux(dut: Dut) -> None:
+    dut.expect_exact('All tests passed', timeout=5)

components/usb/host_test/usbh_layer_test/sdkconfig.defaults

@@ -0,0 +1,4 @@
+
+CONFIG_IDF_TARGET="linux"
+CONFIG_COMPILER_CXX_EXCEPTIONS=y
+CONFIG_UNITY_ENABLE_IDF_TEST_RUNNER=n