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Testing

"If you liked it then you should have put a test on it", Beyonce rule

GUnit

Google.Test/Google.Mock/Cucumber on steroids

• Improve your productivity with GUnit, a library which extends/simplifies Google.Test/Google.Mock and adds support for Gherkin (Behaviour Driven Development) to it.

  • Why it's based on Google.Test/Google.Mock?
    • (+) Google.Test is widely used (The most popular testing framework according to https://www.jetbrains.com/research/devecosystem-2017/cpp)
    • (+) Google.Test is stable
    • (+) Google.Test is powerful
    • (+) Google.Test comes with Google.Mock
    • (+) Google.Test is well documented
    • (-) Google.Test doesn't have support for - gherkin style - tests
    • (-) Google.Test and Google.Mock have a lot boilerplate macros

Motivation Examples

No more base classes and labels as identifiers - GUnit.GTest / GUnit.GTest-Lite

               Google.Test                        |                     GUnit.GTest
--------------------------------------------------+------------------------------------------------------
#include <gtest/gtest.h>                          | #include <GUnit.h>
                                                  |
struct CalcTest : testing::Test {                 | GTEST("Calc Test") {
 void SetUp() override {                          |   Calc calc{};
   calc = std::make_unique<Calc>();               |
 }                                                |   // SetUp
                                                  |
 void TearDown() override { }                     |   SHOULD("return sum of 2 numbers") {
                                                  |     EXPECT_EQ(5, calc->add(4, 1));
 std::unique_ptr<Calc> calc;                      |   }
};                                                |
                                                  |   SHOULD("throw if division by 0") {
TEST_F(ExampleTest, ShouldReturnSumOf2Numbers) {  |     EXPECT_ANY_THROW(calc->div(42, 0));
  EXPECT_EQ(5, calc->add(4, 1));                  |   }
}                                                 |
                                                  |   // TearDown
TEST_F(ExampleTest, ShouldThrowIfDivisionBy0) {   | }
  EXPECT_ANY_THROW(calc->div(42, 0));             |
}                                                 |

Output

[----------] 2 tests from CalcTest                | [----------] 1 tests from Calc Test
[ RUN      ] CalcTest.ShouldReturnSumOf2Numbers   | [ RUN      ] Calc Test
[       OK ] CalcTest.ShouldReturnSumOf2Numbers   | [ SHOULD   ] return sum of 2 numbers
[ RUN      ] CalcTest.ShouldThrowIfDivisionBy0    | [ SHOULD   ] throw if division by 0
[       OK ] CalcTest.ShouldThrowIfDivisionBy0    | [       OK ] Calc Test (0 ms)
[----------] 2 tests from CalcTest (1 ms total)   | [----------] 1 tests from Example (0 ms total)

No more hand written mocks - GUnit.GMock

struct interface {
  virtual ~interface() = default;
  virtual int get() const = 0;
  virtual void foo(int) = 0;
  virtual void bar(int, const std::string&) = 0;
};

               Google.Test                        |                     GUnit.GMock
--------------------------------------------------+------------------------------------------------------
#include <gmock/gmock.h>                          | #include <GUnit.h>
                                                  |
struct mock_interface : interface {               |
  MOCK_CONST_METHOD0(get, int(int));              |
  MOCK_METHOD1(foo, void(int));                   |
  MOCK_METHOD2(bar, void(int, const string&));    |
};                                                |
                                                  |
int main() {                                      | int main() {
  StrictMock<mock_interface> mock{};              |   StrictGMock<interface> mock{};
  EXPECT_CALL(mock, foo(42));                     |   EXPECT_CALL(mock, (foo)(42));
                                                  |
  interface& i = mock;                            |   interface& i = mock.object();
  i.foo(42);                                      |   i.foo(42);
}                                                 | }

Simplified creation and injection of SUT (System Under Test) and mocks - GUnit.GMake

class coffee_maker {
 public:
   coffee_maker(iheater&, ipump&, igrinder&);
   ...
};

               Google.Test                        |                     GUnit.GMake
--------------------------------------------------+------------------------------------------------------
 #include <gtest/gtest.h>                         | #include <GUnit.h>
 #include <gmock/gmock.h>                         |
                                                  |
 TEST(CalcTest, ShouldMakeCoffee) {               | GTEST("Calc Test") {
   StrictMock<mock_heater> heater{};              |   std::tie(sut, mocks) = // auto [sut, mocks] in C++17
   StrictMock<mock_pump> pump{};                  |     make<coffee_maker, StrictGMock>();
   StrictMock<mock_grinder> grinder{};            |
   coffee_maker sut{heater, pump, grinder};       |   EXPECT_CALL(mocks.mock<iheater>(), (on)());
                                                  |   EXPECT_CALL(mocks.mock<ipump>(), (pump)());
   EXPECT_CALL(heater, on());                     |   EXPECT_CALL(mocks.mock<igrinder>(), (grind)());
   EXPECT_CALL(pump, pump());                     |   EXPECT_CALL(mocks.mock<iheater>(), (off)());
   EXPECT_CALL(grinder, grind());                 |
   EXPECT_CALL(heater, off());                    |   sut->brew();
                                                  | }
   sut->brew();                                   |
 }

Support for - Gherkin style - BDD (Behaviour Driven Development) scenarios - GUnit.GSteps

Feature specification

Test/Features/Calc/addition.feature

Feature: Calc Addition
  In order to avoid silly mistakes
  As a math idiot
  I want to be told the sum of two numbers

  Scenario: Add two numbers
    Given I created a calculator with value 0
      And I have entered 20 into the calculator
      And I have entered 30 into the calculator
     When I press add
     Then The result should be 50

Steps Implementation

Test/Features/Calc/Steps/CalcSteps.cpp

#include <GUnit.h>

GSTEPS("Calc*") { // "Calc Addition.Add two numbers"
  auto result = 0;

  Given("I created a calculator with value {n}") = [&](int n) {
    Calculator calc{n};

    Given("I have entered {n} into the calculator") = [&](int n) {
      calc.push(n);
    };

    When("I press add") = [&] {
      result = calc.add();
    };

    Then("The result should be {expected}") = [&](int expected) {
       EXPECT_EQ(expected, result);
    };
  };
}

Usage

SCENARIO="Test/Features/Calc/addition.feature" ./test --gtest_filter="Calc Addition.Add two numbers"

Output

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 tests from Calc Addition
[ RUN      ] Calc Addition.Add two numbers
[    Given ] I have created a calculator with value 0         # CalcSteps.cpp:10
[    Given ] I have entered 20 into the calculator            # CalcSteps.cpp:12
[    Given ] I have entered 30 into the calculator            # CalcSteps.cpp:14
[     When ] I press add                                      # CalcSteps.cpp:16
[     Then ] the result should be 50 on the screen            # CalcSteps.cpp:19
[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (7 ms total)
[  PASSED  ] 1 tests.

Overview

• GUnit.GTest - Google.Test with strings and more friendly macros
  • Test cases with string as names
  • No more SetUp/TearDown (SHOULD clauses)
  • One (GTEST) macro for all types of tests
  • 100% Compatible with tests using GTest
• GUnit.GTest-Lite - lightweight, limited, no-macro way of defining simple tests
• GUnit.GMock - Google.Mock without hand written mocks
  • No more hand written mocks!
  • Support for more than 10 parameters
  • Quicker compilation times
  • Support for unique_ptr without any tricks
  • Support for overloaded operators
  • Support for mocking classes with constructors
  • 100% Compatible with Google Mocks
• GUnit.GMake - Makes creation of System Under Test (SUT) and Mocks easier
  • No need to instantiate SUT (System Under Test) and mocks
    • Automatic mocks injection
• GUnit.GSteps - Behaviour Driven Development
  • Support for - Gherkin style - BDD tests

Quick Start

• If your project is NOT using Google.Test/Google.Mock
  • Follow instructions from https://github.com/google/googletest/tree/master/googletest
• Clone the repository
  • git clone https://github.com/cpp-testing/GUnit.git
• Add GUnit/include directory to your include path
  • -I GUnit/include
• Write some tests...
• Compile and Run!

---

• [Optional] For gherkin support
  • Compile gherkin-cpp

  $cd libs/gherkin-cpp && make lib
  $ls libs/gherkin-cpp
    libgherkin-cpp.a
    libgherkin-cpp.so

  • Add include paths
    • -I GUnit/gherkin-cpp/include
    • -I GUnit/json/src
  • Link with libgherkin-cpp.{a, so}
    • -L libgherkin-cpp
  • Write some feature tests...
  • Compile and Run!

---

• To run GUnit tests/benchmarks

  $mkdir build && cd build && cmake ..
  $make && ctest

Requirements

• C++14
• GTest/GTest-Lite/GMock/GMake
  • libs/googletest - compatible with all versions
• GSteps
  • libs/json
  • libs/gherkin-cpp

Tested compilers

• Linux - GCC-5+
• Linux - Clang-3.7+
• Mac OSx - Xcode-7.3+

User Guide

• GUnit.GTest
• GUnit.GTest-Lite
• GUnit.GMock
• GUnit.GMake
• GUnit.GSteps

FAQ

• C++ Now 2017: Towards Painless Testing

Acknowledgements

• Thanks to Google Open Source for Google.Test/Google.Mock libraries
• Thanks to Eran Pe'er for FakeIt library
• Thanks to Peter Bindels for HippoMocks library
• Thanks to Niels Lohmann for json library
• Thanks to Aslak Hellesøy for gherkin-c library
• Thanks to Cucumber Open Source for cucumber-cpp library