Can soda/ pop drinks effect tests for diabetes?

Yes. Certainly sodas with sugar can raise one's blood sugar, at least temporarily. Even diet sodas can lead to changes from the caffeine, and stimulation of hormones in the GI tract when the taste buds sense something sweet. This is why patients are advised to avoid everything but water when coming in for fasting blood tests. Tests for glycated hemoglobin, or a1c, are not affected by food or drink.