GTK3+ TextView add lines of text with different colors per line

I'm slightly stumped right now, i use a TextView as a status log, new lines added whenever something happens, this is the function i use for that, probably not right but it does work however i can't make it add changing the color of the entire line.

def logtostatus(self, text):
    tvLog = self.tabs['Status'][1].get_children()[0].get_children()[0]
    buf = tvLog.get_buffer()
    start = buf.get_end_iter()
    buf.insert(start, text+"\n")
    end = buf.get_end_iter()

This does insert text, and i had various versions trying to use TextTag's but it refused to work so since i ran out of ideas, i'm asking you all out there, please help, this is driving me nuts.

Thank you

This works for me:

from gi.repository import Gtk

class MainWindow(Gtk.Window):
    def __init__(self):
        super(MainWindow, self).__init__()
        self.connect("destroy", lambda x: Gtk.main_quit())

        tb = Gtk.TextBuffer()
        tv = Gtk.TextView(buffer = tb)

        for color in ("red", "yellow", "green", "blue", "white"):
            tb.insert_markup(
                tb.get_end_iter(),
                '<span color="{:s}">This is a test message</span>\n'.format(color),
                -1)

        self.add(tv)
        self.show_all()

    def run(self):
        Gtk.main()


def main(args):
    mainwdw = MainWindow()
    mainwdw.run()

    return 0

if __name__ == '__main__':
    import sys
    sys.exit(main(sys.argv))

It seems the easiest way to play with colors. This is the result: