Wrong Unittests

[jankatins]

Doing some refactoring work for #188 brought up some interesting "bad" unittests: I changed the tranformation and get_layer code so that it errors if a mapping in aes is used to set a value. From my POW, thats wrong as one can see from the below differences between ggplot2 and our current implementation:

from ggplot.tests.test_basic.test_alpha_density, which now fails

def test_alpha_density():
    gg = ggplot(aes(x='mpg', fill=True, alpha=0.3), data=mtcars)
    assert_same_ggplot(gg + geom_density(), "geom_density_alpha")

vs ggplot2:

library(ggplot2)
gg = ggplot(aes(x=mpg, fill=TRUE, alpha=0.3), data=mtcars)
gg + geom_density()

[jankatins]

I've now changed all unittests to make the setting in the geom_* call without aes(...).

Whats still to be done is to implement fill: currently it can be set to "True", which is not a valied color in ggplot2:

> gg = ggplot(aes(x=mpg,), data=mtcars)
> gg + geom_density(fill=TRUE, alpha=0.3)
Error in col2rgb(colour, TRUE) : ungültiger Farbname in 'TRUE'

You also cannot set different colors than blue.

The problems should be handeled in #191

[jankatins]

What's also open in this issue, is the question whether we want to support setting a mapping to a value: ggplot supports it but it has the funny effect that ggplot interprets it as a discrete variable where all values are the same. I will make some changes to my new code to do the same (silly) behaviour.

[has2k1]

Currently we accept fill = True as a manual aesthetic to mean "yes do fill". It seems rather clear what the user wants. In #252 I have kept this behaviour and the fill value used is the same as the colour of the line.

The only issue is, geom_density(aes(fill=True)) and geom_density(fill=True) would do the filling with different colours. It would have made more sense to be strict with the mappings and less so with the manual aesthetics.

[glamp]

no longer relevant