Contradiction with Genesis 15:18
God's covenant with Abram promised the land to his descendants, which may seem contradictory to leaving nations to test Israel.
Genesis 15:18: In the same day the LORD made a covenant with Abram, saying, Unto thy seed have I given this land, from the river of Egypt unto the great river, the river Euphrates:
Contradiction with Exodus 23:31-33
God orders the Israelites to drive out the inhabitants, contradicting leaving them to test Israel.
Exodus 23:31-33: And I will set thy bounds from the Red sea even unto the sea of the Philistines, and from the desert unto the river: for I will deliver the inhabitants of the land into your hand; and thou shalt drive them out before thee.
Contradiction with Deuteronomy 20:16-18
God commands the Israelites to completely destroy certain nations, which contrasts with leaving them in the land.
Deuteronomy 20:16-18: But of the cities of these people, which the LORD thy God doth give thee [for] an inheritance, thou shalt save alive nothing that breatheth:
Contradiction with Joshua 23:12-13
Israel is warned not to intermarry with the nations, contradicting the presence of these nations to test Israel.
Joshua 23:12-13: Else if ye do in any wise go back, and cleave unto the remnant of these nations, [even] these that remain among you, and shall make marriages with them, and go in unto them, and they to you: