Is it okay to heat a test tube for several minutes for evaporation of solvent inside? I have a mixture of water and a small amount of undissolved solute in a test tube. I want to remove the water in it by evaporation method. Can the test tube carries the evaporation process with a Bunsen burner? I don't want to transfer into different glassware to avoid contamination and reduction of the solution when transferring.
There are two issues here:


Heat from a Bunsen burner is pretty strong. You better make sure whatever is left after the evaporation will survive.
If the solvent is organic (and not super halogenated), this is a terrible idea because you run a serious risk of igniting your solvent vapors.