Closing arguments are set for Thursday in San Antonio. Democrats and minority groups are urging a three-judge panel to invalidate a new redistricting map passed by the GOP-controlled legislature last summer.
Democrats say the map doesn't reflect a statewide surge in Hispanic growth over the past decade. They want more so-called "opportunity districts" for Hispanic voters to elect the candidate of their choice.
The Texas attorney general's office says the map wasn't drawn with prejudice and preserves the voting power of minorities. Republicans testified that alternatives offered by minority groups were drawn in a way that violated Texas law.
The court isn't expected to issue a ruling for several weeks.