You WILL get gas if you pull a line off the filter with or without the pump, they are both lower than the tank.
If you were to be foolish enough to pull a line AND turn on the pump ( assuming it works ), you will have gas sprayed
everywhere up to 15-20 feet away.
Don't be smoking if you try this.
All you REALLY need to do if buy / borrow a fuel pressure gauge that fits the test port and turn on the key. You should see pressure.
About $36 with shipping :

Amazon.com: 0-100 PSI Fuel Injection Pump Injector Tester Test Pressure Gauge Gasoline Cars: Automotive