Unit Testing of a “Blink” Project¶

The goal of this tutorial is to demonstrate how simple it is to use Unit Testing.

Level: Beginner
Platforms: Windows, macOS, Linux

Setting Up the Project ¶

Please navigate to the Quick Start section and create the “Blink Project”.
Create a test directory in the project (on the same level as src) and place a test_main.cpp file in it (the source code is located below).
Run tests using the pio test command.

Project structure ¶

project_dir
├── lib
│   └── README
├── platformio.ini
├── src
│   └── ...
└── test
    └── test_main.cpp

Source files ¶

platformio.ini

; PlatformIO Project Configuration File
;
;   Build options: build flags, source filter, extra scripting
;   Upload options: custom port, speed and extra flags
;   Library options: dependencies, extra library storages
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html


[env:uno]
platform = atmelavr
framework = arduino
board = uno

[env:teensy31]
platform = teensy
framework = arduino
board = teensy31

test/test_main.cpp

#include <Arduino.h>
#include <unity.h>

// void setUp(void) {
// // set stuff up here
// }

// void tearDown(void) {
// // clean stuff up here
// }

void test_led_builtin_pin_number(void) {
    TEST_ASSERT_EQUAL(13, LED_BUILTIN);
}

void test_led_state_high(void) {
    digitalWrite(LED_BUILTIN, HIGH);
    TEST_ASSERT_EQUAL(HIGH, digitalRead(LED_BUILTIN));
}

void test_led_state_low(void) {
    digitalWrite(LED_BUILTIN, LOW);
    TEST_ASSERT_EQUAL(LOW, digitalRead(LED_BUILTIN));
}

void setup() {
    // NOTE!!! Wait for >2 secs
    // if board doesn't support software reset via Serial.DTR/RTS
    delay(2000);

    UNITY_BEGIN();    // IMPORTANT LINE!
    RUN_TEST(test_led_builtin_pin_number);

    pinMode(LED_BUILTIN, OUTPUT);
}

uint8_t i = 0;
uint8_t max_blinks = 5;

void loop() {
    if (i < max_blinks)
    {
        RUN_TEST(test_led_state_high);
        delay(500);
        RUN_TEST(test_led_state_low);
        delay(500);
        i++;
    }
    else if (i == max_blinks) {
      UNITY_END(); // stop unit testing
    }
}

Test results ¶

> pio test -e uno --verbose

Verbose mode can be enabled via `-v, --verbose` option
Collected 1 items

===================== [test/*] Building... (1/3) =======================
Processing uno (platform: atmelavr; board: uno; framework: arduino)
-------------------------------------------------------------------
Verbose mode can be enabled via `-v, --verbose` option
PLATFORM: Atmel AVR > Arduino Uno
SYSTEM: ATMEGA328P 16MHz 2KB RAM (31.50KB Flash)
Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF MODES: FINDER(chain) COMPATIBILITY(soft)
Collected 24 compatible libraries
Scanning dependencies...
No dependencies
Compiling .pio\build\uno\test\output_export.cpp.o
Compiling .pio\build\uno\test\test_main.cpp.o
Archiving .pio\build\uno\libFrameworkArduinoVariant.a
Compiling .pio\build\uno\FrameworkArduino\CDC.cpp.o
Indexing .pio\build\uno\libFrameworkArduinoVariant.a
Compiling .pio\build\uno\FrameworkArduino\HardwareSerial.cpp.o
Compiling .pio\build\uno\FrameworkArduino\HardwareSerial0.cpp.o
Compiling .pio\build\uno\FrameworkArduino\HardwareSerial1.cpp.o
Compiling .pio\build\uno\FrameworkArduino\HardwareSerial2.cpp.o
Compiling .pio\build\uno\FrameworkArduino\HardwareSerial3.cpp.o
Compiling .pio\build\uno\FrameworkArduino\IPAddress.cpp.o
Compiling .pio\build\uno\FrameworkArduino\PluggableUSB.cpp.o
Compiling .pio\build\uno\FrameworkArduino\Print.cpp.o
Compiling .pio\build\uno\FrameworkArduino\Stream.cpp.o
Compiling .pio\build\uno\FrameworkArduino\Tone.cpp.o
Compiling .pio\build\uno\FrameworkArduino\USBCore.cpp.o
Compiling .pio\build\uno\FrameworkArduino\WInterrupts.c.o
Compiling .pio\build\uno\FrameworkArduino\WMath.cpp.o
Compiling .pio\build\uno\FrameworkArduino\WString.cpp.o
Compiling .pio\build\uno\FrameworkArduino\abi.cpp.o
Compiling .pio\build\uno\FrameworkArduino\hooks.c.o
Compiling .pio\build\uno\FrameworkArduino\main.cpp.o
Compiling .pio\build\uno\FrameworkArduino\new.cpp.o
Compiling .pio\build\uno\FrameworkArduino\wiring.c.o
Compiling .pio\build\uno\FrameworkArduino\wiring_analog.c.o
Compiling .pio\build\uno\FrameworkArduino\wiring_digital.c.o
Compiling .pio\build\uno\FrameworkArduino\wiring_pulse.S.o
Compiling .pio\build\uno\FrameworkArduino\wiring_pulse.c.o
Compiling .pio\build\uno\FrameworkArduino\wiring_shift.c.o
Compiling .pio\build\uno\UnityTestLib\unity.o
Archiving .pio\build\uno\libFrameworkArduino.a
Indexing .pio\build\uno\libFrameworkArduino.a
Archiving .pio\build\uno\libUnityTestLib.a
Indexing .pio\build\uno\libUnityTestLib.a
Linking .pio\build\uno\firmware.elf
Checking size .pio\build\uno\firmware.elf
Building .pio\build\uno\firmware.hex
Memory Usage -> https://bit.ly/pio-memory-usage
DATA:    [==        ]  20.0% (used 410 bytes from 2048 bytes)
PROGRAM: [=         ]  12.6% (used 4060 bytes from 32256 bytes)

========================================== [SUMMARY] ==========================================
Environment uno                 [SUCCESS]
Environment teensy31            [SKIP]
================================= [SUCCESS] Took 2.54 seconds =================================

================================= [test/*] Uploading... (2/3) =================================
Processing uno (platform: atmelavr; board: uno; framework: arduino)
-------------------------------------------------------------------
Verbose mode can be enabled via `-v, --verbose` option
PLATFORM: Atmel AVR > Arduino Uno
SYSTEM: ATMEGA328P 16MHz 2KB RAM (31.50KB Flash)
Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF MODES: FINDER(chain) COMPATIBILITY(soft)
Collected 24 compatible libraries
Scanning dependencies...
No dependencies
Checking size .pio\build\uno\firmware.elf
Memory Usage -> https://bit.ly/pio-memory-usage
DATA:    [==        ]  20.0% (used 410 bytes from 2048 bytes)
PROGRAM: [=         ]  12.6% (used 4060 bytes from 32256 bytes)
Configuring upload protocol...
AVAILABLE: arduino
CURRENT: upload_protocol = arduino
Looking for upload port...
Auto-detected: COM18
Uploading .pio\build\uno\firmware.hex

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e950f (probably m328p)
avrdude: reading input file ".pio\build\uno\firmware.hex"
avrdude: writing flash (4060 bytes):

Writing | ################################################## | 100% 0.76s

avrdude: 4060 bytes of flash written
avrdude: verifying flash memory against .pio\build\uno\firmware.hex:
avrdude: load data flash data from input file .pio\build\uno\firmware.hex:
avrdude: input file .pio\build\uno\firmware.hex contains 4060 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 0.48s

avrdude: verifying ...
avrdude: 4060 bytes of flash verified

avrdude: safemode: Fuses OK (E:00, H:00, L:00)

avrdude done.  Thank you.


=============================== [SUMMARY] ================================
Environment uno                 [SUCCESS]
Environment teensy31            [SKIP]
 ====================== [SUCCESS] Took 4.45 seconds ======================

================================== [test/*] Testing... (3/3) ==================================
If you don't see any output for the first 10 secs, please reset board (press reset button)

test\test_main.cpp:30:test_led_builtin_pin_number       [PASSED]
test\test_main.cpp:41:test_led_state_high       [PASSED]
test\test_main.cpp:43:test_led_state_low        [PASSED]
test\test_main.cpp:41:test_led_state_high       [PASSED]
test\test_main.cpp:43:test_led_state_low        [PASSED]
test\test_main.cpp:41:test_led_state_high       [PASSED]
test\test_main.cpp:43:test_led_state_low        [PASSED]
test\test_main.cpp:41:test_led_state_high       [PASSED]
test\test_main.cpp:43:test_led_state_low        [PASSED]
test\test_main.cpp:41:test_led_state_high       [PASSED]
test\test_main.cpp:43:test_led_state_low        [PASSED]
-----------------------
11 Tests 0 Failures 0 Ignored

============================ [TEST SUMMARY] ==============================
test/*/env:uno  [PASSED]
test/*/env:teensy31     [IGNORED]
==================== [PASSED] Took 12.99 seconds =========================

Unit Testing of a “Blink” Project¶

Setting Up the Project¶

Project structure¶

Source files¶

Test results¶

Setting Up the Project ¶

Project structure ¶

Source files ¶

Test results ¶