Stop Greentea tests if a fatal error occurs (#432)

* Stop Greentea tests if a fatal error occurs

* Style

Author: Jamie Smith

TESTS/configs/greentea_baremetal.json5

@@ -15,7 +15,10 @@
         // Allow lots of reboots so that we don't get in a situation where the MCU refuses to boot
         // after crashing and being reflashed (since some MCUs/flash tools don't reset the
         // crash data RAM)
-        "platform.error-reboot-max": 99999,
+        "platform.error-reboot-max": 2147483648,
+
+        // Emit a KV pair when an assert fail or hardfault occurs
+        "platform.mbed-error-emit-greentea-kv": true,
 
         // Enable mbed trace prints for tests that use it
         "mbed-trace.enable": true,

TESTS/configs/greentea_full.json5

@@ -9,7 +9,10 @@
         // Allow lots of reboots so that we don't get in a situation where the MCU refuses to boot
         // after crashing and being reflashed (since some MCUs/flash tools don't reset the
         // crash data RAM)
-        "platform.error-reboot-max": 99999,
+        "platform.error-reboot-max": 2147483648,
+
+        // Emit a KV pair when an assert fail or hardfault occurs
+        "platform.mbed-error-emit-greentea-kv": true,
 
         // Enable mbed trace prints for tests that use it
         "mbed-trace.enable": true,

platform/mbed_lib.json

@@ -164,6 +164,10 @@
         "minimal-printf-set-floating-point-max-decimals": {
             "help": "Maximum number of decimals to be printed when using minimal printf library",
             "value": 6
+        },
+        "mbed-error-emit-greentea-kv": {
+            "help": "Option that can be used when building Greentea tests. Causes the mbed_error() function (caused by assert failures and HardFaults) to emit a Greentea key-value pair indicating that an error has occurred.",
+            "value": null
         }
     },
     "target_overrides": {

platform/source/mbed_error.c

@@ -661,6 +661,18 @@ static void print_error_report(const mbed_error_ctx *ctx, const char *error_msg,
 #endif
 
     mbed_error_printf("\n-- MbedOS Error Info --\n");
+
+    // Print error summary for Greentea tests if desired.
+#ifdef MBED_CONF_PLATFORM_MBED_ERROR_EMIT_GREENTEA_KV
+    // Flag that error occurred. Print this first because the default test runner
+    // just ends the test right away when it sees this.
+    mbed_error_printf("{{mbed_error;1}}\r\n");
+
+    mbed_error_printf("{{mbed_error_module;%d}}\r\n", error_module);
+    mbed_error_printf("{{mbed_error_code;%d}}\r\n", error_code);
+    mbed_error_printf("{{mbed_error_message;%s}}\r\n", error_msg);
+    mbed_error_printf("{{mbed_error_location;0x%" PRIx32 "}}\r\n", ctx->error_address);
+#endif
 }
 #endif //ifndef NDEBUG
 

tools/python/mbed_os_tools/test/host_tests/base_host_test.py

@@ -171,12 +171,24 @@ def __default_end_callback(self, key, value, timestamp):
         """
         self.notify_complete(value == 'success')
 
+    def _default_mbed_error_callback(self, key: str, value: str, timestamp: float):
+        # End the test immediately on error by default. This prevents wasting test runner time
+        # by waiting for the timeout to expire!
+        self.log("Detected target fatal error. Failing test...")
+        self.notify_complete(False)
+
     def __assign_default_callbacks(self):
         """! Assigns default callback handlers """
         for key in self.__consume_by_default:
             self.__callbacks[key] = self.__callback_default
         # Register default handler for event 'end' before assigning user defined callbacks to let users over write it.
         self.register_callback('end', self.__default_end_callback)
+        self.register_callback("mbed_error", self._default_mbed_error_callback)
+
+        # Register empty callbacks for the error details, to prevent "orphan event" warnings
+        self.register_callback("mbed_error_module", self.__callback_default)
+        self.register_callback("mbed_error_code", self.__callback_default)
+        self.register_callback("mbed_error_message", self.__callback_default)
 
     def __assign_decorated_callbacks(self):
         """