fix(modem): Added test-cases that exercise mode transitions

Author: david-cermak

components/esp_modem/test/host_test/main/test_modem.cpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Unlicense OR CC0-1.0
  */
@@ -247,3 +247,88 @@ TEST_CASE("Test CMUX protocol by injecting payloads", "[esp_modem]")
         CHECK(ret == command_result::OK);
     }
 }
+
+TEST_CASE("Command and Data mode transitions", "[esp_modem][transitions]")
+{
+    auto term = std::make_unique<LoopbackTerm>();
+    auto loopback = term.get();
+    auto dte =  std::make_shared<DTE>(std::move(term));
+    CHECK(term == nullptr);
+
+    esp_modem_dce_config_t dce_config = ESP_MODEM_DCE_DEFAULT_CONFIG("APN");
+    esp_netif_t netif{};
+    auto dce = create_SIM7600_dce(&dce_config, dte, &netif);
+    CHECK(dce != nullptr);
+
+    // UNDEF -> CMD (OK)
+    uint8_t resp[] = "DISCONNECTED\n";
+    loopback->inject(&resp[0], sizeof(resp), sizeof(resp), /* 10ms before injecting reply */100, 0);
+    loopback->write(nullptr, 0); /* this triggers sending the injected response */
+    CHECK(dce->set_mode(esp_modem::modem_mode::COMMAND_MODE) == true);
+    loopback->inject(nullptr, 0, 0, 0, 0); /* reset injection, use synchronous replies now */
+    // CMD -> CMD (Fail)
+    CHECK(dce->set_mode(esp_modem::modem_mode::COMMAND_MODE) == false);
+
+    // Forcing transition to CMD (via UNDEF)
+    // CMD -> UNDEF (OK)
+    CHECK(dce->set_mode(esp_modem::modem_mode::UNDEF) == true);
+    // UNDEF -> CMD (OK)
+    CHECK(dce->set_mode(esp_modem::modem_mode::COMMAND_MODE) == true);
+
+    // CMD -> DATA (OK)
+    CHECK(dce->set_mode(esp_modem::modem_mode::DATA_MODE) == true);
+    // DATA -> CMD (OK)
+    CHECK(dce->set_mode(esp_modem::modem_mode::COMMAND_MODE) == true);
+}
+
+TEST_CASE("CMUX mode transitions", "[esp_modem][transitions]")
+{
+    auto term = std::make_unique<LoopbackTerm>();
+    auto dte = std::make_shared<DTE>(std::move(term));
+    CHECK(term == nullptr);
+
+    esp_modem_dce_config_t dce_config = ESP_MODEM_DCE_DEFAULT_CONFIG("APN");
+    esp_netif_t netif{};
+    auto dce = create_SIM7600_dce(&dce_config, dte, &netif);
+    CHECK(dce != nullptr);
+    // UNDEF -> CMUX (OK)
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MODE) == true);
+    // CMUX -> DATA (Fail)
+    CHECK(dce->set_mode(esp_modem::modem_mode::DATA_MODE) == false);
+    // CMUX back -> CMD (OK)
+    CHECK(dce->set_mode(esp_modem::modem_mode::COMMAND_MODE) == true);
+}
+
+TEST_CASE("CMUX manual mode transitions", "[esp_modem][transitions]")
+{
+    auto term = std::make_unique<LoopbackTerm>();
+    auto dte = std::make_shared<DTE>(std::move(term));
+    CHECK(term == nullptr);
+
+    esp_modem_dce_config_t dce_config = ESP_MODEM_DCE_DEFAULT_CONFIG("APN");
+    esp_netif_t netif{};
+    auto dce = create_SIM7600_dce(&dce_config, dte, &netif);
+    CHECK(dce != nullptr);
+
+    // Happy flow transitions of Manual CMUX transitions
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_MODE) == true);
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_EXIT) == true);
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_MODE) == true);
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_SWAP) == true);
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_DATA) == true);
+    // Cannot test CMUX_MANUAL_DATA -> CMUX_MANUAL_COMMAND with our mocked terminal for now
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_EXIT) == true);
+
+    // Check some out of order manual transitions, most of them are allowed,
+    // but some fail as modem layers report issues with specific steps
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_SWAP) == false); // cannot go directly to SWAP
+    CHECK(dce->set_mode(esp_modem::modem_mode::UNDEF) == true);
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_SWAP) == true);  // can go via UNDEF
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_EXIT) == false); // EXIT is allowed, but CMUX terms don't exist
+    CHECK(dce->set_mode(esp_modem::modem_mode::UNDEF) == true);
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_MODE) == true);  // Enter CMUX (via UNDEF)
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_DATA) == true);  // Go directly to DATA mode
+    CHECK(dce->set_mode(esp_modem::modem_mode::CMUX_MANUAL_EXIT) == true);  // Exit CMUX
+    CHECK(dce->set_mode(esp_modem::modem_mode::UNDEF) == true);             // Succeeds from any state
+
+}