Code examples for "Dynamic Typing Makes for Testability" article

class-a.java

class A
{
    private B b;

    public A(B b)
    {
        this.b = b;
    }

    public void store()
    {
        // Stores important things into the database
        this.b.store();
    }
}

class-a.rb

class A
  def initialize(b)
    @b = b
  end

  def store
    # Stores important things into the database
    @b.store
  end
end

class-b.java

class MockB extends B
{
    public boolean storeCalled = false;

    public void store()
    {
        this.storeCalled = true;
    }
}

class ATest
{
    public void storeTest()
    {
        MockB b = new MockB();
        A a = new A(b);

        a.store();

        assert(b.storeCalled);
    }
}

final-b.java

class B
{
    public final void store()
    {
        // Writes to the database
    }
}

gymnastics.java

class MockB
{
    private boolean mock;
    private B b;

    public boolean storeCalled = false;

    public MockB(boolean mock = false)
    {
        this.mock = mock;

        if(!this.mock)
        {
            this.b = new B();
        }
    }

    public void store()
    {
        if(!this.mock)
        {
            this.b.store();
        }
        else
        {
            this.storeCalled = true;
        }
    }
}

interface-b.java

class MockB implements B
{
    public boolean storeCalled = false;

    public void store()
    {
        this.storeCalled = true;
    }
}