Exercise (FH): class rectangle

Building class rectangle Upon class point

In the project you have set up in Exercise (FH): class point, you’ll find an a test suite for a class rectangle, again together with a sparse implementation thereof.

Continuing the tradition of test driven development, continually extend class rectangle by adding the following tests one by one.

Important

Whenever an object of class rectangle is passed as a parameter, do not pass that object by copy! Use references instead!

Default Constructor

code/tests/rectangle-default-ctor.cpp
#include <gtest/gtest.h>

#include <rectangle.h>

TEST(rectangle_suite, default_ctor)
{
    const rectangle r;
}

Coordinates

code/tests/rectangle-coordinates.cpp
#include <gtest/gtest.h>

#include <rectangle.h>

TEST(rectangle_suite, coordinates)
{
    {
        const rectangle r;
        ASSERT_EQ(r.bottom_left(), point(0,0));
        ASSERT_EQ(r.top_right(), point(0,0));
        ASSERT_EQ(r.top_left(), point(0,0));
        ASSERT_EQ(r.bottom_right(), point(0,0));
    }

    {
        const point bottom_left{1,2};
        const point top_right{8,6};
        const rectangle r{bottom_left, top_right};

        ASSERT_EQ(r.bottom_left(), point(1,2));
        ASSERT_EQ(r.top_right(), point(8,6));
        ASSERT_EQ(r.top_left(), point(1,6));
        ASSERT_EQ(r.bottom_right(), point(8,2));
    }
}

Width, Height, Area

code/tests/rectangle-area.cpp
#include <gtest/gtest.h>

#include <rectangle.h>

TEST(rectangle_suite, area)
{
    {
        const rectangle r;

        ASSERT_EQ(r.width(), 0);
        ASSERT_EQ(r.height(), 0);
        ASSERT_EQ(r.area(), 0);
    }

    {
        const rectangle r{point(3,4), point(8,6)};

        ASSERT_EQ(r.width(), 5);
        ASSERT_EQ(r.height(), 2);
        ASSERT_EQ(r.area(), 10);
    }
}

(In-)Equality

In addition to make the test run, please

  • implement that one in the rectangle.cpp file

  • do not pass the right hand side operand by copy (rationale: a rectangle is 16 bytes in size, so passing objects by reference is cheaper [1]).

code/tests/rectangle-operator-eq-ne.cpp
#include <gtest/gtest.h>

#include <rectangle.h>

TEST(rectangle_suite, operator_eq_ne)
{
    const rectangle r1(point(1,2), point(3,4));
    const rectangle r2(point(1,2), point(3,5));

    bool b;

    b = (r1 == r2);
    ASSERT_FALSE(b);

    b = (r1 == r1);
    ASSERT_TRUE(b);

    b = (r1 != r1);
    ASSERT_FALSE(b);

    b = (r1 != r2);
    ASSERT_TRUE(b);
}

+=

Implement that one in the rectangle.cpp file, please.

code/tests/rectangle-operator-plus-equal-vec.cpp
#include <gtest/gtest.h>

#include <rectangle.h>

TEST(rectangle_suite, operator_plus_equal_vec)
{
    rectangle r(point(3,4), point(8,6));
    const point vec(1,2);

    const rectangle r1 = r += vec;

    ASSERT_EQ(r.bottom_left(), point(4,6));
    ASSERT_EQ(r.top_right(), point(9,8));

    ASSERT_EQ(r, r1);
}

+

Implement that one in the rectangle.cpp file, please.

code/tests/rectangle-plus-vec.cpp
#include <gtest/gtest.h>

#include <rectangle.h>

TEST(rectangle_suite, plus_vec)
{
    const rectangle r(point(3,4), point(8,6));
    const point vec(1,2);

    const rectangle r1 = r + vec;

    ASSERT_EQ(r1.bottom_left(), point(4,6));
    ASSERT_EQ(r1.top_right(), point(9,8));

    ASSERT_EQ(r, rectangle(point(3,4), point(8,6)));
}

<< (std::ostream)

Implement that one in the rectangle.cpp file, please.

code/tests/rectangle-operator-ostream.cpp
#include <rectangle.h>

#include <sstream>
#include <gtest/gtest.h>

TEST(rectangle_suite, operator_ostream)
{
    const rectangle r(point(3,4), point(8,6));

    std::ostringstream buf;
    buf << r;

    ASSERT_EQ(buf.str(), "((3,4),(8,6))");
}

Footnotes