How to merge 3 dataframes in pandas based off of some common key

Question

I have three dataframes below:

Zip Dataframe:

Zipcode    Lat  Long 
12345      24    51
54321      12    15

Locations Dataframe:

Code    Zip
a1    12345
b2    54321

TestData Dataframe:

   LocationID    source  dest
   a1            a1      b2
   b2            b2      a1

I want to add source zip, source lat, source long, dest zip, dest lat, dest long columns to the TestData df.