add tests for Elasticity of GDP
add tests for Elasticity of GDP

zrisher/webapp-public,OpenSourcePolicyCenter/PolicyBrain,OpenSourcePolicyCenter/PolicyBrain,zrisher/webapp-public,OpenSourcePolicyCenter/webapp-public,OpenSourcePolicyCenter/PolicyBrain,OpenSourcePolicyCenter/PolicyBrain,OpenSourcePolicyCenter/webapp-public,zrisher/webapp-public,OpenSourcePolicyCenter/webapp-public,zrisher/webapp-public,OpenSourcePolicyCenter/webapp-public