def METHOD_NAME(self):
    """Test that existing raster is overridden if desired"""
    runivar_source = SimpleModule("r.univar", flags="g", map="rename_3")
    self.runModule(runivar_source, expecting_stdout=True)
    original_runivar_source = text_to_keyvalue(
        runivar_source.outputs.stdout, sep="=", skip_empty=True
    )
    runivar_target = SimpleModule("r.univar", flags="g", map="exists")
    self.runModule(runivar_target, expecting_stdout=True)
    original_runivar_target = text_to_keyvalue(
        runivar_target.outputs.stdout, sep="=", skip_empty=True
    )
    module = SimpleModule("g.rename", raster=["rename_3", "exists"], overwrite=True)
    self.assertModule(module)
    self.assertRasterExists(
        "exists",
        msg="Destination (here: existing) map (to) should exist after rename",
    )
    self.assertFalse(
        is_map_in_mapset("rename_3", type="raster"),
        msg="Source map (from) should not exist after rename",
    )
    runivar = SimpleModule("r.univar", flags="g", map="exists")
    self.runModule(runivar, expecting_stdout=True)
    new_runivar = text_to_keyvalue(runivar.outputs.stdout, sep="=", skip_empty=True)
    # both these tests are probably redundant but let's test thoroughly
    if keyvalue_equals(
        dict_a=original_runivar_target, dict_b=new_runivar, precision=1e-7
    ):
        msg = "Raster map did not change. It probably wasn't overwritten."
        self.fail(msg)
    if not keyvalue_equals(
        dict_a=original_runivar_source, dict_b=new_runivar, precision=1e-7
    ):
        unused, missing, mismatch = diff_keyvalue(
            dict_a=original_runivar_source, dict_b=new_runivar, precision=1e-7
        )
        if mismatch:
            msg = "Destination raster map is not the same as source."
            msg += " It probably wasn't overwritten.\n"
            msg += "Difference between r.univar of maps:\n"
            msg += "mismatch values"
            msg += " (key, reference, actual): %s\n" % mismatch
            self.fail(msg)