Simple Intent - jUnit test fails

I am currently a bit puzzled about Intent extras. I know that the so called extras are a Bundle and the Bundle is internally a map.

And if I put something into this map, with intent.putExtra("someName", "someValue");, I expect that there is now a key called "someName" present in the map. But it isn't, according to my very simple unit test.

    public void testIntent(){
    assertTrue("true != true", true);
    assertFalse("false != false", false);

    final String extraName = "IamAnExtra";
    final String extraValue = "IamAValue";
    Intent intent = new Intent();
    intent.putExtra(extraName, extraValue);

    assertTrue("hasExtra==false", intent.hasExtra(extraName));
    }

Now ths results in the following:

junit.framework.AssertionFailedError: hasExtra==false

What kind of magic is happening behind the intent-code? I know that it is normally working. Is the map cached and written only if I send the intent? Thank you in advance!

Edit:

I added the line assertNotNull("extras == null", intent.getExtras()); which also fails.

And I checked the code from the methods putExtra and getExtras, which is:

    public Intent putExtra(String name, String value) {
    if (mExtras == null) {
        mExtras = new Bundle();
    }
    mExtras.putString(name, value);
    return this;
    }

and

    public Bundle getExtras() {
    return (mExtras != null)
            ? new Bundle(mExtras)
            : null;
    }

So if the member mExtras is null, then null is returned for getExtras. But putExtra will create a new Bundle instance for mExtras, therefore mExtras should not be null. I'm confused.